Taro Leaves Drying Kinetics and Monolayer Moisture Content

Taro Leaves Drying Kinetics and Monolayer Moisture Content INTRODUCTION |1 A study on the drying kinetics and monolayer moisture content of taro leaves This research was aimed to develop dehydrated products based on Taro leaves and finding out the effect of drying parameters such as loading density and temperature on that control the drying kinetics. To determine the end point of drying studies on the sorption isotherm was conducted. From the moisture sorption isotherm data, the monolayer moisture content was estimated by Braunauer-Emmett-Teller (BET) equation using data up to a water activity (aw) of 0.52 and monolayer moisture content was found to be 8.92 g water per 100 g solid for taro leaves. By using another most important model, GAB (Guggenheim-Anderson-DeBoer) model, using data up to aw=0.9, the monolayer moisture content of taro leaves was found to be 19.78g water per 100 gm solid. INTRODUCTION It is estimated that by 2020, the population of Bangladesh will be as high as 200 million, which means that there is a need to produce more food from the limited land resources. In this context, there is a need to explore alternate food crops, which could supply food in food insecurity situations. â€Å"Taro† can be the alternative to the other vegetables for developing and under developed country. Apart from acting as cheap energy and dietary source, this crop provides other micronutrients, vitamins and dietary fiber as well. In Bangladesh, taro is used as vegetable throughout the country. Corms and cormels are used as starchy vegetables whereas leaves and leaf stalks are used as ‘shak’. During famine, a large number of people reportedly survive simply on food materials made by boiling the corms, cormels, stolons, leaf stalks and leaves of different varieties of Taro. The subfamily Colocasioideae of family Araceae consists of three edible tubercrops, namely taro (Colocasia esculenta Schott), `tannia (Xanthosoma spp.) and giant Taro (Alocasia spp.). Among these crops, taro and tannin are cultivated to a larger extent, while giant taro is not as common as commercial crop like the other two. In general, these are crops of third world countries, particularly grown in Africa and Asia. About 88 % of the total world acreage is in Africa which produces about 80% of total production (Onwueme, 1978). Among the three crops, taro is more common in South-East Asia. It is one of the ancient crops with an interesting history blending with the evolution of agricultural systems (Gopalan et al., 1974). A large number of horticultural varieties of taro are widely cultivated in Bangladesh and still larger varieties grow wild. During the rainy season when other vegetables are in scarcity in Bangladesh this taro goes a long way to meet the demand for vegetables. The leaves, petioles, stolons, corms and cormels, and indeed all the parts of some taro are taken as food in large quantities by the rural population in our country. Hence the use of Taro as vegetables, both leaves and roots, in the diets of the people of our country assumes special and added importance. The taro has also medicinal value. Processed Bishknchu is used in Ayurvedic medicine for the treatment of rheumatism. Juice from petioles and whole leaves are used as antiseptic to check bleeding from minor injury in the rural areas of Bangladesh (Chowdhury, 1975). The possibility of wider use of the Taro leaves as vegetables crops in our country may be ascribed to their unusual environmental adaptability and ease of cultivation. The lowland types grow in standing water which is rarely possible for other crops. The taro can be produced with minimum capital investment. Growing of this crop does not require any special technological skill. Their keeping quality in most cases is excellent. The best way of preserving the leasfy vegetables is drying or dehydration. This process costs less, then other preserving methods and require simple instrument. The type and conditions of the blanching treatment prior to drying affect the retention of ascorbic acid, carotene, and ash in the dried vegetables. The sun-dried vegetables had inferior color, texture and acceptability compared to the vegetables dried in the cabinet dryer. In the mechanical dryer, desired temperature and airflow could be maintained. Compared to sun/solar drying, higher airflow and temperature can be used in mechanical drying. This leads to high production rates and improved quality products due to shorter drying time and reduction of the risk of insect infestation and microbial spoilage as well as minimum nutrient loss. Since mechanical drying is not dependent on sunlight so it can be done as and when necessary. Based on the above information, the present experiment was broadly aimed to study on development of shelf stable taro (Colocassia esculenta) leaves product. The specific objectives of this study are as follows: To determine the composition of fresh and processed Taro leaves To develop the isotherm To study the drying characteristics of taro leaves during mechanical and vacuum drying To study the storage stability of processed taro leaves Materials and methods 3.2.3 Sorption isotherm studies The moisture sorption properties of dried Taro leaves were determined at room temperature under conditions of various relative humidity (11-93% RH) in the vacuum desiccators. The various RH conditions were achieved in vacuum desiccators using saturated salt solutions. The following salt solutions (Table. 3.1) of known water activity were used for the study (Islam, 1980). Table 3.1: Water activity of saturated salt solution Petri dishes were used for preparing saturated salt solution. The various salts were put in the Petri dish and water is added to give a saturated condition. The method involved putting a small accurately weighed about 1g sample in a previously weighed Petri dish into desiccators contained saturated salt solutions. The sample and the solution was separated a perforated plate to avoid mixing. The desiccators were evacuated to less than 50 Torr. At various intervals, the vacuum was broken with air, the sample weighed and replaced in the desiccators, which was then re-evacuated. The sample was weighed daily in the initial period and less often, as the sample started to reach equilibrium. Weighing was continued until the sample weights were constant two days in row. In the mid-1970s, water activity came to the forefront as a major factor in understanding the control of the deterioration of reduced moisture, drugs and biological systems (Labuza, 1975). It was found that the general modes of deterioration, namely physical and physicochemical modifications, microbiological growth, and both aqueous and lipid phase chemical reactions were all influenced by the thermodynamic availability of water (water activity) as well as the total moisture content of the system. Control of initial moisture content and moisture migration is critical to the quality and safety of foods. Ideally, food manufacturers develop products with defined moisture contents to produce a safe product with optimum shelf- life. Quality and safety factors that the manufacturer must consider are microbial stability, physical properties, sensory properties, and the rate of chemical changes leading to loss of shelf-life. Water activity or the equilibrium relative humidity of a system is defined as: Where Vapor pressure of water in equilibrium with the dry system Saturation vapor pressure of pure water at the same temperature. Sorption properties of floods (equilibrium moisture content and monolayer moisture) are essential for the design and optimization of many processes such as drying, packaging and storage (Muhtaseb et al., 2002).The moisture sorption isotherms show the equilibrium amount of water sorbed onto a solid as a function of steady state vapor pressure at a constant temperature (Bell and Labuza, 2000). There are many empirical equations that describe this behavior, but the water sorption properties at various RHs should be experimentally determined for each material. The general shape of the isotherm, specific surface area of the sample, reversibility of moisture uptake, presence and shape of a hysteresis loop provide information on the manner of interaction of the solid with water (Swaminathan and Kildsig, 2001). Sorption properties are important in predicting the physical state of materials at various conditions, because most structural transformations and phase transitions are significantly affected by water (Roos, 1995). Langmuir (1917) developed an equation based on the theory that the molecules of gas are adsorbed on the active sites of the solid to form a layer one molecule thick (monolayer). The Brunauer-Emmett-Teller (BET) sorption model (Brunauer et al.1938) is often used in modeling water sorption particularly to obtain the monolayer value (Eq. 2.10) which gives the amount of water that is sufficient to form a layer of water molecules of the thickness of one molecule on the adsorbing surface (Bell and Labuza 2000, Roos, 1995). The BET monolayer value has been said to be optimal water content for stability of low-moisture materials (Labuza, 1975 and Roos, 1995). The BET equation was developed based on the fact that sorption occurs in two distinct thermodynamic states; a tightly bound portion and multilayer having the properties of bulk free water (Zografi and Kontny, 1986). The BET equation is: Where, = the measured moisture at water activity = the monolayer moisture content (the optimal moisture content for maximum storage stability of a dry food); c = the isotherm temperature dependence coefficient (energy constant) Vanchy (2002) determined the moisture sorption isotherm of Whole milk powder (WMP). The WMPs were stored at 20 and 35 °C under 11%, 22% and 33% relative humidity . The monolayer moisture content was 4.8%, (solids not fat basis) at 0. 11 using the BET equation and 5.1 % at 0.23 according to the GAB equation. Nikolay et al. (2005) determined the moisture equilibrium data (adsorption and desorption) of semi-defatted (fat 10.6 % wet basis) pumpkin seed flour using the static gravimetric method of saturated salt solutions at three temperatures 10 °C, 25 °C, and 40 °C, found that the equilibrium moisture content decreased with the increase in storage temperature at any given water activity. They fitted the experimental data to five mathematical models (modified Oswin, modified Halsey, modified Chung-Host, modified Henderson and GAB). The GAB model was found to be the most suitable for describing the sorption data. The monolayer moisture content was estimated using the Brunauer-Emmett-Teller (BET) equation. The BET model (Brunauer et al. 1938) gives the best fit to the data at aw of up to 0.5 (Bell and Labuza 2000, Roos 1995). Guggenheim-Anderson-de Boer (GAB) sorption model (Anderson 1946, Boer 1953, Guggenheim 1966) introduces a third state of sorbed species intermediate to the tightly bound and free states. The GAB equation has a similar form to BET, but has an extra constant, K (equation 2.11). BET is actually a special case of GAB. The GAB equation is: Isotherm equations are useful for predicting the water sorption properties of a material, but no equation gives results accurate throughout the entire range of water activities. According to Timmermann (2003), the GAB monolayer value is always higher than the BET monolayer value. Prediction of water sorption is needed to establish water activity and water content relationship for materials (Roos, 1995) Where m = the measured moisture at water activity; = the monolayer moisture content (the optimal moisture content for maximum storage stability of a dry food), =the GAB multi-layer constant; c=the isotherm temperature dependence coefficient (energy constant). The GAB model can be used to a maximum water activity of 0.9. The following procedure is suggested by Biozt (1983) to fit data on water activities and equilibrium moisture content. Equation (2.11) can be transformed as follows: Where Equation (2.12) indicates that GAB equation is a three-parameter model. The water activity and equilibrium moisture content date are regressed using equation (2.12) and values of three coefficients, and are obtained. From these coefficients, the values of k,, and c can be calculated. To overcome this weakness of the GAB equation, modifications of the equation have been proposed (Schuchmann et al. 1990; Timmermann and Chirife 1991). Timmermann and Chirife (1991) used one additional parameter in the GAB model and studied the so-called third stage of sorption using experimental data of starch with satisfactory results. Isotherm equations are useful for predicting the water sorption properties of a material, but no equation gives results accurate throughout the entire range of water activities. According to Timmermann (2003), the GAB monolayer value is always higher than the BET monolayer value. Prediction of water sorption is needed to establish water activity and water content relationship for materials (Roos, 1995). Results and discussion: The sorption isotherm is an extremely valuable tool for food scientist because it can be used to predict potential changes in food stability, for selection of packaging, for selection of ingredient and for predicting drying time. A sorption isotherm for dehydrated taro leaves obtained by Vacuum oven drying (VOD) was established to determine how the taro product will behave in a confined environment. To obtain the moisture sorption isotherm, moisture content (dry basis) versus water activity were plotted on linear graph paper (Figure 4.1). The results shown in Figure 4.1 (tabulated data given in Appendix-II, Table 2.1), indicate that samples absorb little water particularly at lower aw ( Figure 4.1 Graphical presentation of sorption isotherm of Taro The water sorption isotherm of taro follows the shape of the sigmoid type isotherm. The resultant curve is caused by the combination of colligative effects (physical properties of solution), capillary effects, and surface-water interactions (Bell and Labuza, 2000). A distinct knee usually indicates a formation of a well-defined monolayer. The monolayer moisture content was estimated using the Brunauer-Emmett-Teller (BET) equation. The BET equation is an extension of the Langmuir relationship that accounts for multilayer coverage. BET equation was used (eq. 2.10) to calculate monolayer moisture content (mo) and energy constant (C). mo represents the optimal moisture for maximum storage stability in the dry state. Results obtained from BET equation are shown in Table 4.2. Table 4.2 Data for BET and GAB methods From the slope and intercept of BET equation (Appendix II, Figure 2.1), monolayer moisture content and energy constant of taro leaves calculated for VOD samples. The monolayer moisture content of taro leaves was found to be 8.92g water per 100 g solid (Table 4.2). The calculated monolayer moisture content are greater than those found by Islam (1980) who reported 5.5 for potato slice and 6 for potato powder and by Kamruzzaman (2005) who reported 7.52 for aroids. Another important model of sorption isotherm behavior stated by GAB (Guggenheim-Anderson-DeBoer) in equation 2.11 and 2.12 to determine the monolayer moisture content of food products. This is very important for safe level of storage of food. Dry foods are usually considered to be most stable to chemical reactions if their moisture content is at or near the BET monolayer (Labuza et al., 1970). Usually air dried products are dried to moisture content corresponding to aw 0.6 (Nickerson and Sinskey, 1977). From this study it is seen that VOD taro leaves give 25% (Figure 4.1) moisture content at 0.6 aw. From this standpoint, freeze dried products are considered best for sorption studies (Islam, 1980). It may be mentioned here that the current study was concerned with adsorption isotherm so as to avoid risk due to hysteresis effect. At same moisture content adsorption path gives higher water activity than desorption path. Thus product dried to safe aw level according to adsorption isotherm will be even safer when it follows desorption path. After fitting data (Appendix II) the following figure was developed and from the developed equation the monolayer moisture content of taro leaves were found for GAB model. Fig. 4.2 Graphical presentation of GAB model of sorption isotherm From the developed Figure (4.2) and equation (4.1) the coefficients found, and were -0.121, 0.114 and -0.003 respectively (Table 4.2). Taking k= 0.9 and found the monolayer moisture content 19.78gm water per 100 gm solid. It is shown that the standard GAB equation is adequate to describe experimental data for water activity values up to 0.90 but fails to adequately describe the experimental data when data in the range of aw 0.9-1.0 are included in the calculation.

Critical evaluation †John Steinbeck-Of Mice and Men and Robert Ludlum-The Bourne Identity Essay

Through the history of man; mathematicians, philosophers, teachers, and scientists have molded and shaped our world. These men and women, young and old, are responsible for the continually growing knowledge in today’s youth. Upon studying the most influential educators, it was proven that writers and authors sustain every element of the society we live; love, passion, romance, adventure, drama, science fiction, and non-fiction. All of these categories exist for only one purpose, to entertain the minds who absorb the material. Entertaining authors make an exceptional story and none other than Robert Ludlum and John Steinbeck accomplish this feat better. In order to further understand these authors thirst to provide edge-of-the-seat entertainment, their past and present must be explored. Although these authors lived in two diverse locations, their driving desire for knowledge appears the same. Ludlum and Steinbeck attended college after high school, majoring in English. After graduating from Salinas High School in 1919, Steinbeck attended Stanford University from 1920-1925. Two years after Steinbeck left to pursue his writing career in New York, Robert Ludlum was born on May 25, 1927. Ludlum was educated privately and at the Chesire Academy, Connecticut. After appearing is school theatricals, he acted in the comedy Junior Miss on Broadway at the age of sixteen. His degree includes: B.A., Wesleyan University, Middletown, 1951. Having never graduated from Stanford University, Steinbeck’s life for the most part was low profile even after the publishing of his first books, â€Å"Cup of Gold† (1929), â€Å"The Pastures of Heaven† and â€Å"To a God Unknown†, which were all inadequately acknowledged by the literary world. â€Å"Tortilla Flat† (1935) was the noticeable turning point in Steinbeck’s literary career receiving the California Commonwealth Club’s Gold Medal for best novel. Steinbeck continued writing, and The Grapes of Wrath (1939) won him the Pulitzer Prize. The Nobel Prize was awarded to John Steinbeck for Literature in 1962 â€Å"†¦for his realistic as well as imaginative writings, distinguished by a sympathetic humor and a keen social perception.† 1 Twenty-nine Academy Award nominations and four Academy Awards were given for revision of John Steinbeck’s stories. Literature lost one of its most accomplished and distinguished writers on December 20, 1968, in New York City; John Steinbeck died at the age of 66. However, on a more positive note, New York City was also the place where literature bore Robert Ludlum. Ludlum can be described as a modern day author. He is a well-known author writing twenty-one novels and selling over 290 million books in thirty-two different languages. Ludlum started his literary career relatively late because he was working in 1. Mobel Lectures; literature 1901-4967 the theatre as an actor and producer. One of the primary reasons Ludlum is such a suspenseful writer is due to the fact that he was born in an age where movies grabbed the attention of the public eye. In the 1950s, Ludlum worked as a stage and television actor. After producing 300 stage productions for New York and regional theatre, Ludlum wrote his first novel, â€Å"The Scarlatti Inheritance† (1971). Few writers are able to grasp global attention using unbelievable plots that spin into engrossing tales. John Steinbeck and Robert Ludlum are comparable writers. These two authors are very accomplished and their novels reputations speak for themselves. John Steinbeck’s Of Mice and Men and Robert Ludlum’s The Bourne Identity are the focus of this evaluation. Their works signify literary techniques that contribute to theme. The central theme in Of Mice and Men written by John Steinbeck: human fates are constantly controlled by outside forces. The techniques he uses for example: repetition and symbolism are extremely successful in getting across his very cynical views on this theme. Similar techniques are used in Robert Ludlum’s The Bourne Identity. Uniquely writing; many of Ludlum’s techniques are present in his writing, but the reader is too engrossed in the story to recognize them. However, Ludlum writes meticulously in his story plots. When evaluated, the reader can distinguish that repetition and symbolism are also used as literary techniques that contribut e to theme. Steinbeck and Ludlum use the technique of repetition to effectively build up the climax of the tragedy. In Of Mice and Men, Lennie unintentionally killed his mouse when petting it. This situation repeats itself further in the novel when Slim gives Lennie a puppy. When playing with the animal, Lennie gave the puppy a disciplining thump for biting him and he killed it. An incident, such as this, will be the downfall of George and Lennie. Near the end of the novel, Lennie strokes Curley’s wife’s hair. He holds too tightly and she gets frightened. â€Å"Lennie was in a panic.† 2 Climaxing, he attempts to quiet her, â€Å"Don’t you go yellin’, he said, and he shook her, and her body flopped like a fish. And then she was still, for Lennie had broken her neck.† 2 The repetition of unintentional death foreshadows a negative outcome for Lennie, his sealed fate. This action brought upon his own murder by George who shot him in the back of the head out of mercy for everything else that was weak and helpless. In this act of violence, George would not be considered a murderer, in fact, quite the opposite. George, instead, would be deemed a savor because he did Lennie a favor. 2. Steinbeck; 91 The Bourne Identity uses repetition in a similar fashion. The central character Jason Bourne faces memory loss, crippling him from discovering his true identity. His instincts and intelligence help guide him. The quote: â€Å"You are not helpless. You will find your way.† 3 is repeated on several occasions, which foreshadows success on Jason’s behalf. Jason’s rhetorical behavior when faced with stressful and difficult situations ends in same violent manner. â€Å"Bourne grabbed the Frenchman in front of him now, his left arm around the man’s throat, his right hand tearing at the man’s left ear.† 4 Without thinking, Jason reacts to the situation with poise and precision. Jason’s rhetorical skills evoke his memory enough to enable him to think and act on his own to avoid death or capture. â€Å"Whenever you observe a stress-and you have the time-do your damndest to project into it. Associate as freely as you can; let words and images fi ll your mind. In them you may find clues.† 5 This quote is nearly repeated again, â€Å"Whenever you’re in a stress situation-and there’s time, of course-do exactly as you would when you project yourself into one you’re observing. Let your mind fall free, let whatever thoughts and images that surface come cleanly. Try not to exercise any mental discipline. Be a sponge; concentrate on everything and nothing. Specifics may come to you, certain repressed conduits electricity prodded into functioning.† 6 except there is added tactics, which suggests that Jason is constantly learning. Through repetition Jason persistently advances his skills to obtain his past by varying his appearance, â€Å"Change your hair†¦you change your face.† 7 Soon after his skills advanced, Jason learned that his real name is David Webb who turns out as a young Far East scholar. Webb received a new identity from the Central intelligence (CIA) as Jason Bourne, a black ops agent. His primary objective was to kill Carlos, another far more advanced assassin, but was betrayed. As the plot twists, the CIA has given Jason quite a few hoops to jump through for his own survival. The climax builds to this particular moment in the novel, when Jason reverses the situation and uses the training the CIA gave him to kill the assassin Carlos. The climax appears to have truth because not only has Jason stopped being on the defensive side of this ‘live or die’ game, but also his proficient skills have drawn him to his past profession to kill or be killed; fate. The interfering CIA has lost control of Bourne; however he is drawn back to his past line of work, which could result in death, so he ultimately loses. It could be said that Jason Bou rne was born to be a professional assassin under anyone’s control. 3. Ludlum; 39, 43, 83 4. Ludlum; 64 5. Ludlum; 50 6. Ludlum; 82 7. Ludlum; 116, 161 Another technique that demonstrates John Steinbeck’s view of fate is the symbolism. Near the end of the novel, â€Å"A watersnake glided smoothly up the pool, twisting its periscope head from side to side, and it swam the length of the pool and came to the legs of a motionless heron that stood in the shallows. A silent head and beak lanced down and plucked it out by the head, and the beak swallowed the little snake while its tail waved frantically.† 8 The heron, stationary and patient, symbolizes fate, while the watersnake, vulnerable and unaware, its victim. The watersnake would most likely symbolize George. Not only does the Heron symbolize fate, it also symbolizes Lennie the burden to their dream. Steinbeck illustrates his view on fate once more by word choice. Words like ‘lanced’, ‘plucked’, and ‘waiting’ suggest that Steinbeck believes that fate strikes assertively and specifically. Similarly, Robert Ludlum uses symbolism to project the same idea. Symbolism appears not as evident as repetition; however, present nonetheless. The CIA seems to be the entity or government corporation that symbolizes fate. Every element in the novel can be drawn back to something that the CIA has caused. Ludlum and Steinbeck believe fate to be all the same. In Ludlum’s case, the CIA’s intricate plans and organized operations parallel Steinbeck’s idea that fate acts in the same manner, assertively and specifically. Of Mice and Men and The Bourne Identity are literally written in identical fashions. Steinbeck and Ludlum use character driven dialogue to tell the story. The point-of-views transpose between first person (the main characters) and third person (the narrator). The first person prospective uniquely projects to the reader each of the character thoughts and actions. The first person prospective gives a clear understanding of what exactly will happen, without all of the excess narration. However, the narration does an excellent job in describing the setting among other elements, such as flow between events. The ‘events’ or chapters are present in both novels. Ludlum uses three books within his novel along with thirty five chapters because The Bourne Identity is far longer than the six chapters Of Mice and Men. This technique is apparent for the sole purpose of changing locations in the story with ease; in The Bourne Identity Jason and his companion travel to different countries, and in Of Mice and Men the only change of location appears within the town and ranch. These two books were written very similarly. Both switched between first and third person depending on what the best way to tell the story was. By changing point of views, Ludlum and Steinbeck were able to develop their themes more thoroughly. The technique of changing perspectives allowed the reader to identify with the main characters, but at the same time, know vital information that would be needed to understand the story. 8. Steinbeck; 99 Robert Ludlum and John Steinbeck are exceptional authors. There novels: The Bourne Identity and Of Mice and Men, respectively, have Robert Latta’s praise. Woohoo, right? There are more positive, than negative, statements to be discussed. Particularly, Ludlum’s story is far more intriguing than Steinbeck’s. The plot and characters all are attention getters. The idea that a man with no memory has instincts that are above any normal man, and has answers to every question, except his name, is fascinating. The only downfall to Ludlum’s work appears to be the length of his novel, five hundred some odd pages, that turns out to be a lot of reading time. Steinbeck’s novel length; however, fits the taste well, only one hundred some pages. The ‘olden story’ in Steinbeck’s novel, gets negative feedback because its entire plot stimulated nothing more than closing eye lids. Praising the literary device of repetition, this gave some indication that what was being read over again would prove useful in assembling a critical evaluation essay. The repetition also forces the information into your brain, meaning it holds significance. Moreover, the theme portrayed among these two novels had some relevance with our current lives, which also served another purpose to reading them Overall, the novels ended up balancing one another. A positive recommendation can be made for both these novels because something can be learned. WORKS CITED Lectures, Mobel. â€Å"The Nobel Prize in Literature 1962.† [online] http://www.nobel.se/literature/laureates/1962/press.html Ludlum, Robert. The Bourne Identity. New York: Richard Marek, 1975 Steinbeck, John. Of Mice and Men. New York: Penguin Books, 1978

Library Management System Essay

Name of the Project Vision Online Library Online Library is a system, which maintains books in the server in any format. It allows storing books, documents, audio and video files. User can Search and open documents by giving a simple query. Online Library Management System is a system, which maintains books, documents, audio/video files. To use this system user must be a member in this. Then user allowed storing books, documents, A/V files. Then user can search by giving a simple query. It is very difficult search books manually. Online Library makes easy. Deliverables / Functional Specifications Online Library uses user internal feedback from user to improve search process in every searching. It also uses indexing to locate documents very fast in searching which relate to query. Main aim of online Library system is providing highly relevant documents in very short period after giving query. It is just like Search Engine. It uses Vector space Model and Probabilistic Model to find similarity coefficient, weights. User Interface Requirements Database Centralized ONLINE LIBRARY BY M.SATHISH KUMAR Page 2 Browser based DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 Requirements Integration Requirements Preferred Technologies J2EE Technologies i.e. JSP, Servlets, jdbc Frontend: – Html, JavaScript, Java Server pages. Backend: – Oracle 10g. Hardware Requirement Pentium 4 processor with 256 MB RAM, 40 GB Hard disk Web based Interface ONLINE LIBRARY BY M.SATHISH KUMAR Page 3 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 INTRODUCTION ONLINE LIBRARY BY M.SATHISH KUMAR Page 4 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 INTRODUTION Online Library Management System is a system, which maintains books, documents, audio/video files. To use this system user must be a member in this. Then user allowed storing books, documents, A/V files. Then user can search by giving a simple query. It is very difficult search books manually. Online Library makes easy. Online Library uses user internal feedback from  user to improve search process in every searching. It also uses indexing to locate documents very fast in searching which relate to query. Main aim of online Library system is providing highly relevant documents in very short period after giving query. It is just like Search Engine. It uses Vector space Model and Probabilistic Model to find similarity coefficient, weights. Existing System Early days Libraries are managed manually. It required lot of time to record or to retrieve the details. The employees who have to record the details must perform their job very carefully. Even a small mistake would create many problems. Security of information is very less. Report generations of all the information is very tough task. Maintenance of Library catalogue and arrangement of the books to the catalogue is very complex task. In addition to its maintenance of member details, issue dates and return dates etc. manually is a complex task. All the operations must be performed in perfect manner for the maintenance of the library without any degradation, which may finally result in the failure of the entire system. Benefits of automation Automation is procedure of converting a traditional system in to a computer organization. To overcome the defects of the existing system automation was introduced by the computerization of organization we get many benefits. ONLINE LIBRARY BY M.SATHISH KUMAR Page 5 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 The main objectives of undertaking this project are: ï‚ · ï‚ · ï‚ · ï‚ · ï‚ · ï‚ · ï‚ · ï‚ · The students will register them through Online Individually each member will have his account through which he can access the information he needs. Books, documents, A/V files are stored in server. User will enter simple  query in text box and click on the Search button. Server takes the request and processes it. Returns hyper links of documents with their names, ranks weights and description. If the user clicks on name of the document then it will open with respective program and rank of document will increase for that query.(for example .pdf files with Adobe Reader) User can upload documents, books and a/v files. Time consuming is low, gives accurate results, reliability can be improved with the help of security. Proposed System: To solve the inconveniences as mentioned above, an Online Library proposed. PROCESS LOGIC: 1. The user inputs data (e.g.: fills out an HTML form and clicks the submit button.) 2. The client (Browser) sends the data to the web server in a standard format (i.e., the GET method or the POST method). 3. The web server launches the program specified by the user and feeds it the input (form) data. 4. The program (e.g.: servlet) processes the form data and produces another HTML page. 5. The web server sends back the HTML page to the browser. The web browser then displays the response page. ONLINE LIBRARY BY M.SATHISH KUMAR Page 6 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 ANALYSIS Analysis is the process of understanding the existing system by gathering and interpreting the facts, diagnosing the problems. It is not just to determining the how best to solve the manual system problems, it should also work for the system observes the feasibility of system then design, coding phases will be executed. Analysis phase delivers requirements specification .The system specification serves as an interface between the designer and  developer as well as between developers and users. This describes the external behavior of the software without bothering about the internal implementation. Specification must be carefully checked for suitability, omission, inconsistencies and ambiguities. Problem analysis is performed to getting a clear understanding of the needs of the clients and the users and what exactly desired form the software. Analysis leads to the actual specification. During the process of analysis, a massive amount of information is collected in the form of interviews, questionnaires, and information from documentation, and so forth. The major problem during analysis is resolving how to organize the information from documentation, and so forth. So the information can be effectively evaluated for completeness and consistency. ONLINE LIBRARY BY M.SATHISH KUMAR Page 7 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 REQUIREMENT SPECIFICATION FUNCTIONAL MODEL / USE CASE MODEL IDENTIFYING ACTOR: 1. Administrator: He should register new Users, Delete Users etc. He can upload new documents, Documents, and A/V files. 2. User: He should register in site in order to access books. He can search for books. He can upload new books, documents, and A/V files into server. IDENTIFYING SCENARIOS: A Scenario is a scene, which explains a particular situation in more visualized model. A scenario consists of actors, scenes, and flow of events. In our project, we have the following scenarios: Scenario for Searching of EBooks, Document or A/V file: Scene Name Actors Flow of events Searching for books. User/Administrator User Opens home page of site. It will display text box and Search button. User simply enter query into text box, clicks on Search button. Browser sends request to the server. Server search documents for query and sends hyperlinks to documents (with weight, ranks, and a small description about document) in order of relevance to the query. ONLINE LIBRARY BY M.SATHISH KUMAR Page 8 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 Scenario a for Opening EBook, Document or A/V file: Scene Name Actors Flow of events Opening Book, Document, or A/V file. User / Administrator User clicks on hyperlink of Document by reading description about document that had displayed below hyperlink. Then browser sends a request to the server again. The request contains name of document which user wants to open. The server will increase rank for document with respect to query into order to increase the relevance. Then server sends the document file in the form of response to browser. Now browser will open the document by using related application program on client system. (For example if server sent .mp3 file then browser opens it by using audio player, which installed on client‟s computer. Of course, Browser needs permeation of System Administrator to access application program.) ONLINE LIBRARY BY M.SATHISH KUMAR Page 9 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 Scenario for Uploading a EBook, Document or A/V file into Server: Scene Name Actors Flow of events Uploading Administrator / User First User clicks on hyperlink of â€Å"Upload document†. Then browser sends request to upload file. Server return a webpage to browser it contains text box and browse button. By clicking on browse button a file window is displayed which allows to user to select a document from clients computer. After selecting document users click on upload button. Server checks for its extension. If document is.exe file server will not allow uploading file for the purpose of security. Then server insert name of document into documents table with unique document id. Then server creates index for document and insert into indexes table. Server returns a webpage, which contains confirmation and document id. ONLINE LIBRARY BY M.SATHISH KUMAR Page 10 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 Scenario for Modifying Users: Scene Name Actors Flow of events Modifying Users Administrator If login user is admin then homepage contains a special Hyperlink that â€Å"modify user.† If admin clicks on that hyperlink he will navigate to another webpage which contains details of users. In that admin can modify user details admin can delete users who violated terms of site. IDENTIFYING USE CASES: A use case is a description of systems behaviour from a user‟s standpoint. It is a tried and true technique for gathering systems requirement from a user‟s point of view. ONLINE LIBRARY BY M.SATHISH KUMAR Page 11 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 USE CASE DIAGRAMS Use case diagram for entire Online Library System: ONLINE LIBRARY BY M.SATHISH KUMAR Page 12 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 Use Case Diagram for Searching: Use case Diagram for Uploading file: ONLINE LIBRARY BY M.SATHISH KUMAR Page 13 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 SEQUENCE DIAGRAMS Sequence Diagram for Searching: ONLINE LIBRARY BY M.SATHISH KUMAR Page 14 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 Sequence Diagram for uploading file: ONLINE LIBRARY BY M.SATHISH KUMAR Page 15 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 Sequence Diagram for Opening file: ONLINE LIBRARY BY M.SATHISH KUMAR Page 16 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 COLLABORATION DIAGRAMS Collaboration Diagram for Searching: ONLINE LIBRARY BY M.SATHISH KUMAR Page 17 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 Collaboration Diagram for uploading file: Collaboration Diagram for Opening file: ONLINE LIBRARY BY M.SATHISH KUMAR Page 18 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 ACTIVITY DIAGRAMS Activity Diagram for Searching: ONLINE LIBRARY BY M.SATHISH KUMAR Page 19 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 Activity Diagram for Uploading file: ONLINE LIBRARY BY M.SATHISH KUMAR Page 20 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 Activity Diagram for Opening file: ONLINE LIBRARY BY M.SATHISH KUMAR Page 21 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 CLASS DIAGRAMS DBHandler Class: DBHandler is respnosible for performing all operations which are need interaction with Database. It perform all operation in database like inserting document, creating index, inserting query, mating database consistency , creating tables, recovering database when database crashed. It highly simplifies maintains of database. Adminstrator need not worry about database at any time. ONLINE LIBRARY BY M.SATHISH KUMAR Page 22 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 VectroSpaceModel Class: VectorSpaceModel is class it responsible for calculating similarity coefficients of documents with respect to query. After calculating similarity coefficient it passes documents with similarity coefficients to probabilistic model class, which will finds weights using similarity coefficients. ProbabilisticModel Class: Probabilisticmodel class responsible for calculating weights for documents using similarity coefficients. After calculating weights, it will get ranks for documents from rank table. And return documents to Search class. ONLINE LIBRARY BY M.SATHISH KUMAR Page 23 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 Read Class: Read class for responsible for reading text from text files. It will read text from different format of text files. For example .doc, .pdf, .xls, .txt, .html etc. It read reads text and clean text and returns as string. If the file is not text file then it will return name and extension of file as string. Search Class: Search Class acts as driver class. It does not perform any tasks. It makes all class working together. ONLINE LIBRARY BY M.SATHISH KUMAR Page 24 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 DEPLOYMENT DIAGRAM ONLINE LIBRARY BY M.SATHISH KUMAR Page 25 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 DESIGN SOFTWARE STRUCTURE: Software is fundamental characteristic of computer software. Software structure is to decompose the complex groups of module into sub modules i.e., Process, Menus, Inputs and Reports. The most general form of the software structure is the network. The structure is the network. The structure inside a complex processing node might consist of concurrent processes executing in parallel and communication through some combination of shared variables. DATABASE DESIGN: Planning the Database: The most important consideration in designing the database is how the information will be used. ïÆ'Ëœ Business activities that will use the database to perform. ïÆ'Ëœ Business rules that apply to these activities ïÆ'Ëœ Data wanted to maintain in the database The main objectives of designing a database are ïÆ'Ëœ ïÆ'Ëœ ïÆ'Ëœ Data integration Data integrity Data independence DATA INTEGRATION: In a database, information from several files is co-ordinate, accessed and operand upon as though it is single file. ONLINE LIBRARY BY M.SATHISH KUMAR Page 26 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 Logically, the information is centralized, physical, the data may be located facilities. Design Methodology: Design is concerned with identifying software components, specifying relationships among component, specifying software structure and providing a blue print for the implementation phase. Design consists of three types: 1. Architectural Design 2. Detail Design 3. External Design Architectural Design: Architectural Design involves identifying the software components, decoupling and decomposing them into processing modules and conceptual data structure and specifying relationships among the components. Detailed Design: Detailed design is concerned with the details of how to package the processing modules and how to implement the processing algorithms, data structure and interconnection among modules and data structure. GUI based design: In order to have a better understanding over the system design, it is appropriate to know the actual designing in terms of the development platform and the way in which the GUI are designed to satisfy the requirements of the user. The analysis of the design aspects of this package is proposed External design. External design of software involves conceiving, planning and specifying the external observable characteristics in different devices connected though data communication ONLINE LIBRARY BY M.SATHISH KUMAR Page 27 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 of a software product. This includes reports and display formats. External design begins analysis phase it continues into the design phase. DATA INTEGRITY: Data integrity means storing all the data in single place and allow each application to access it. This approach results in more consistent, on update being sufficient to achieve a new record status for all the applications, which use it. This leads to less data redundancy, data items need not be duplicated, requirement. DATA INDEPENDENCE: Data independence is the insulation of application programs from changing aspects of physical data organization. This objective seeks to allow changes in the content and organization of physical data without reprogramming of applications and to allow modifications to application programs without the reorganizing the physical data. Normalization: Data structuring is refined through a process called normalization. Normalization is a formal process of developing data structures in a manner that eliminates decomposition redundancy and promotes integrity. of complex records into simple It is a step-by-step records to reduce a reduction in the direct access storage  redundancy, inconsistencies and remove anomalies. There are several normal forms to be followed in normalization process. The most important and widely used are: ï‚ · ï‚ · ï‚ · ï‚ · ONLINE LIBRARY BY M.SATHISH KUMAR Page 28 First Normal Form Second Normal Form Third Normal Form DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 First Normal Form: A table is said to be in first normal form if the intersection of any column and row contains only value. Method: This is identifying a suitable identifier from the pool of normalized data. Remove any item that repeat within a single value of this key to another relation bringing with them the identifier key to form part of new composite key in the relation. Second Normal Form: For a table to be in the second normal form it should also be in the first normal form and the values in every column are functionally dependent on the complete primary key. Method: Examine every column and section whether its value depend on the whole of  the compound key or just some parts of it. Remove key. Third Normal Form: For a table to be in the third normal form transitively dependent on the primary key. Method: Examine every non-key column with every other non-key column. If the value of the non-key column depends on the other non-key column then remove the columns to separate table. it should be in the those that depend only on part of the key to a new table with that part as the primary second normal form and the values in every non-key column are not ONLINE LIBRARY BY M.SATHISH KUMAR Page 29 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 De Normalization: The normalization process helps in reducing to a great extent but sometimes when information is required from more than one table, at a fast rate , it is desirable to have some degree of redundancy in table . Their deliberate introduction of redundancy for a highly improved performance is referred to as † De Normalization† . DATABASE TABLES: 1. QUARRIES: The QUARRES table can store quarries entered by user with unique ID (QID). It is stores unique quarries irrespective order of words and case of letters. 2. DOCUMENTS: The DOCUMENTS table can hold name of documents, which are in server with unique ID for every document. 3. WORDS: The WORDS table can store words, which are in documents. This table plays key role in creating index for documents. This table contains a unique ID and words column. Unique words can be stored in this table irrespective of case of letters. 4. RANKS: The RANKS table can hold rank and weight for each document with respect to query. This table contains four columns. QID and DID are refer QID of QUERRIES and DID of DOCUMENTS table respectively. 5.  INDEX: The INDEX table helps to search engine while searching for documents, which are relate to query given by user. Simply it makes fast Searching. It contains two columns WID, DID refer WID of WORDS, DID of DOCUMENTS tables. 6. USERDETAILS: The USERDETAILS can hold details of users. Username, user-id, password etc. ONLINE LIBRARY BY M.SATHISH KUMAR Page 30 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 ENTITY RELATIONSHIP DIAGRAMS ONLINE LIBRARY BY M.SATHISH KUMAR Page 31 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 ABOUT THE SOFTWARE INTRODUCTION: HTML stands for hyper text makeup language. It is a language used to create hypertext documents that have hyperlinks embedded in them. You can build web pages. It is only a formatting language and not a programming language. Hyperlinks are underlined or emphasized words or locations in a screen that leads to other documents, W W W is a global, Interactive, dynamic, cross Platform, graphical hypertext information system. The idea behind hypertext is that instead of reading text in rigid linear structure you can easily jump from one point to another. You can Navigate through the information based on your interest and preferences. HYPERMEDIA HTML pages with audio and video files linked to them are called Hypermedia. HTML is platform independent. HTML IS PLATFORM INDEPENDENT: If you can access internet, you can access WWW, Irrespective of your operating system and the operating system to the web server. All you require to view and unload the HTML files, which are on the WWW, are a browser and internet connection. WEB IS DISTRIBUTED: The information on the WWW is distributed through out the world. You can access it with a few mouse clicks. You do not have to store it on your machine. Information on the Web is dynamically updateable. As the information is at the site where it is published, the people who publish it can change it any time. HTML is a language for describing structured documents, HTML describes the structures of documents – lists, headings, paragraphs Etc. Elements of web documents are labeled through the usage of HTML tags, It is the tags that describe the documents. Anything that is not a tag part of the Document itself. ONLINE LIBRARY BY M.SATHISH KUMAR Page 32 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 The Static Web When the World Wide Web was born, it consisted of static Web sites. Web sites consisted of static documents (mostly HTML pages) that were accessible through Web servers. Users used Web browsers to access these Web sites. A Web browser communicated with a Web server over the Hyper Text Transfer Protocol (HTTP). Using an HTTP request, the browser communicated with the Web server and asked to get access to a certain document. The Web server managed a set of documents stored on a file system. When asked for a document, it would retrieve it and return it within an HTTP response: HTML DOES NOT DESCRIBE PAGE LAYOUT: World for windows or lotus improve for example, have different styles for Headings, font, Size, and identification. HTML does not have all these. Based on the plat form , exact placement or appearance of any element will change. There may be or may not be fonts installed. By separating the structure of the document and its appearance, a program, that reads and understands HTML can make formatting decisions based on capabilities of the individual platform . In addition to providing the networking functions to retrieve documents, Web browsers are also HTML formatters. ONLINE LIBRARY BY M.SATHISH KUMAR Page 33 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 They parse and format documents and display them on the screen. Different rowsers show data differently. ADVANTAGES : A HTML document is small and hence easy to send over the net. It is small because it does not include format information. HTML documents are cross platform compatible and device independent. You only need a HTML reliable browser to view them. Font names, locations Etc.. are required. Currently the standard fully supported is HTML 2.0 & HTML 3.0 is in use. It supports. Centered and right aligned text. Tables . Math equations Text and image alignment JAVA INTRODUCTION Java is an intercepted language. Though it bears a close resemblance to C++ , it is different from it in many ways. It is a smaller,  portable, purely object oriented Language that eliminates many of the sources of bugs and complexities that are common with C Or C++ . JAVA FEATURES: Java is simple, Object Oriented, Intercepted, Robust, Secure Architecture neutral, Portable, has high performance, multi threaded and dynamics. It is easier To use Java because it’s syntax is similar to C and C++, more so when it eliminates components of C that causes bugs and memory leaks and hence a lot less debugging, Java provides a powerful Set of pre-tested libraries that give us the ability to use advanced features even with few lines of Code. OBJECT ORIENTED Java is an Object oriented programming Language that uses software objects called CLASESS and it is based on reusable, extensible code. This implies we can use Java’s classes, which are sets of variables and method s, as ONLINE LIBRARY BY M.SATHISH KUMAR Page 34 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 templates to create other Classes with added functionality without the need to write the code from Scratch. The Application can be made small and easy to develop if we plan the class hierarchy well. Robust: Java is Robust because, the language removes the use of pointers and The Java Runtime System manages the memory for us. Java gives us automatic bounds checking for arrays, so that they cannot reside in an address space which is not allocated for them. Automatic memory management is taken care of by the Garbage Collector. Interpreted: Java is interpreted; hence the development cycle is much faster. Java needs to compile for a single, virtual machine and then the code can run on any machine that has JVM ported to it. Secure: Java is secure, so user can download Java programs from anywhere. Java provides extensible compile time checking followed by a multi layered level of runtime Checking. Architecture Neutral: Java is architecture neutral, so user applications are portable across multiple platforms. Java’s Applications are written and compiled into Byte Code for JVM, Which emulates an actual hardware chip. The Java Interpreter installed at the client, so applications need not be written for various platforms separately converts byte Code to machine code. Java further ensures that the applications are the same on every platform by strictly defining the sizes of the basic data types and their behaviour. Dynamic: Java is Dynamic., so the applications are adapted to changing environments, Java’s architecture allows the user to dynamically load classes at runtime from any where on the network, which means that the user can add functionality to applications by simply linking in new classes. ONLINE LIBRARY BY M.SATHISH KUMAR Page 35 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 JDBC OVERVIEW What is JDBC? JDBC is a Java TM API for executing SQL statements. It consists of a set of classes and interfaces written in the JAVA programming language that makes it easy to send SQL statements to virtually any relational database. In other words, with the JDBC API, it isn’t necessary to write one program to access a Sybase database, another program to access an Oracle database, another program to access an Informix database, and so on. One can write a single program using the JDBC API, and the program will be able to send SQL statements to the appropriate database. And, with a program written in the JAVA programming language, one doesn’t have to worry about writing different programs to run on different platforms. The combination of JAVA and JDBC lets a programmer write it once and run it anywhere. JAVA, being robust, secures, easy to use, easy to understand, and automatically downloadable on a network, is an excellent language basis for database applications. What i s needed is a way for JAVA applications to talk to  variety of different databases. JDBC is the mechanism for doing this. JDBC extends what you can do in JAVA. For example, with JAVA and the JDBC API, it is possible to publish a web page containing an applet that uses information obtained from a remote database. Or an enterprise can use JDBC to connect all its employees (Even if they are using a conglomeration of Windows, Macintosh and Unix machines) to one or more internal databases via. An Internet. With more and more programmers using the JAVA programming language, the need for easy database access from JAVA is continuing to grow. MIS managers like the combination of JAVA and JDBC because it makes disseminating information easy and economical. Business can continue to use their installed databases and access information easily even if it is stored on different database management systems. Development time for new applications is short. Installation and version controls are greatly simplified. A programmer can write an application or an update once, put it on the server and everybody has access to the latest version and for business selli ng information services, JAVA and JDBC offers better way of getting out information updates to ONLINE LIBRARY BY M.SATHISH KUMAR Page 36 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 external customers. Various ways to use JDBC are discussed in. What Does JDBC Do? Simply put, JDBC makes it possible to do three things: Establishes connection to databases. Send SQL statements. Process the results. JDBC is a Low-level API and a base for Higher-Level API. JDBC is a â€Å"Low-level† interface, which means that it is used to invoke SQL commands directly. It works very well in this capacity and is easier to use than other database connectivity APIs, but it was designed also to be a base upon which to build higher-level interfaces and tools. A higher-level interface is â€Å"User-friendly†, using a more understandable or more convenient API that is  translated behind the scenes into a Low level interface such as JDBC. So why not just use ODBC from Java? The answer is that you can use ODBC from JA V A, but this is best done with the help of JDBC in the form of the JDBC-ODBC Bridge. The question now becomes â€Å"Why do you need JDBCT’ There are several answers to this question: 1. ODBC is not appropriate for direct use from Java because is uses a C interface. 2. Calls from Java to native C code have a number of drawbacks in the security, 1. implementation, robustness, and automatic probability of applications. A literal translation of the ODBC API into a Java API world not desirable. For example, Java has no pointers, and ODBC makes copious use from, including the notoriously error-prone generic pointer â€Å"void *†. You can think as JDBC as ODBC translated into an object-oriented interface that is natural for Java programmers. 2. ODBC is hard to learn. It mixes simple and advanced features together, and it has complex options even for simple queries. JDBC, on the other ONLINE LIBRARY BY M.SATHISH KUMAR Page 37 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 hand, was designed for a wide range of programmers and keeps simple things simple. 3. A Java API like JDBC is needed in order to enable an â€Å"all-Java† solution. When ODBC is used, the driver manager and drivers must be manually installed on every client machine. When the JDBC driver is written completely in JAVA, however, JDBC code is automatically installed, portable, and secure on all Java platforms from network computers to mainframes. In summary, the JDBC API is natural JAVA interface is to the basic SQL abstractions and concepts. It builds an odbc rather than starting from search, so programmers familiar with odbc will find it very easy to learn JDBC. JDBC retains the basic design features of ODBC; infarct, both interfaces are based on the x/Open SQL CU( call level interface). The big difference is that JDBC builds on and reinforces the style and virtues of  Java, and of course, it is easy to use. ADVANTAGES. Until now, the middle tier has typically been written in languages such as C or C++, which offer fast performance. However, with introduction of optimizing compilers, translating Java byte code into efficient machinespecific code, it is becoming practical to implement the middle tier in Java. This is a big plus, making it possible to take advantage of Java’s robustness, multi-threading and security features. SOL Conformance Structured Query Language(SQL) is the standard language for accessing relational databases. One area of difficulty is that almost most DBMSs(Database Management Systems) gives a standard form of SQL for basic functionality, they do not conform to the more recently defined standard SQL syntax or semantics for more advanced functionality. For example, not all databases support stored procedures or outer joins, and those that do are not consistent with each other. It is hoped that the portion of SQL that is truly standard will expand to include more functionality. In the mean time, however, the JDBC API must support SQL as it is. One way the JDBC API deals with the problem is to allow any query string to be passed through to an underlying DBMS driver. This means that an application is iTee to use as much SQL functionality is desired, but it runs the risk of receiving an error on some DBMS. In fact an application query need not even be an SQL, or it may be a specialized derivation of SQL designed for specific DBMS(for document or image queries). For example, a second way JDBC deals with the problems of SQL conformance is to provide ODBC style escape clauses. Which are discussed in SQL Escape Syntax in Statement objects. This escape syntax allows a programmer to use SQL ONLINE LIBRARY BY M.SATHISH KUMAR Page 38 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 functionality item within a JDBC program. The ODBC API is a natural choice for Java developers because it offers easy database access for Java  applications and applets. Because JDBC brings together Java and databases, the remainder of the topic gives a brief overview of each. JDBC DRIVERS The JDBC drivers that we are aware of at this time fit into one of four categories. 1. JDBC-ODBC bridge plus ODBC Driver: The JavaSoft bridge product provides JDBC access via ODBC drivers. Note that ODBC binary code and in many cases database client code must be loaded on each client machine that uses this driver. As a result, this kind of driver is more appropriate on a corporate network where client installations are not a major problem, or for applications server code written in Java in a three-tier architecture. 2. Native-Api partly – JAVA Driver: This kind of driver converts JDBC calls into calls on the client api for Oracle, sybase, Informix, DB2, or other DBMS. Note that, like the bridge driver this style of driver requires that some binary code be loaded on each client machine. 3. JDBC-Net all– JAVA Driver: This driver translates JDBC calls into a DBMS independent net protocol, which is then translated to a DBMS protocol by a server. This net server middleware is able to connect its all-Java clients to many different databases. The specific protocol used depends on the vendor. In general, this is the most flexible JDBC alternative. It is likely that all vendors of this solution will provide products suitable for internet use. In order for these products to also support internet access, they must handle the additional requirements for security, access through fire walls, etc., that the web imposes. Several vendors are adding JDBC drivers to their existing database middleware products. 4. Native – Protocol all-Java Driver: This kind of driver converts JDBC calls into the network protocol used b: dbms’s directly. This allows a direct call from the client machine to the dbms server and is a practical solution for internet access. Since many of ONLINE LIBRARY BY M.SATHISH KUMAR Page 39 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 these protocols are proprietary, the database vendors themselves will be the  primary source. Several database vendors have these in progress. Eventually, we expect that categories 3 and 4 will be the preferred way to access databases from JDBc. Driver categories 1 and 2 are in term solutions where direct all-Java drivers are not yet available. Category 4 is in some sense the ideal; however, there are many cases where category 3 may be preferable: e.g., where a thin dbms in dependent client is desired, or if a dbms-independent protocol is standardized and implemented directly by many dbms vendors. SERVLETS Introduction: The Java web server is JavaSoft’s own web Server. The Java web server is just a part of a larger framework, intended to provide you not just with a web server, but also with tools. To build customized network servers for any Internet or Intranet client/server system. Servlets are to a web server, how applets are to the browser. About Servlets: Servlets provide a Java-based solution used to address the problems currently associated with doing server-side programming, including inextensible scripting solutions, platform-specific APIs, and incomplete interfaces. Servlets are objects that conform to a specific interface that can be plugged into a Java-based server. Servlets are to the server-side what applets are to the client-side – object byte codes that can be dynamically loaded off the net. They differ from applets in that they are faceless objects (without graphics or a GUI component). They serve as platform independent, dynamically loadable, pluggable helper byte code objects on ONLINE LIBRARY BY M.SATHISH KUMAR Page 40 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 the server side that can be used to dynamically extend server-side  functionality. For example, an HTTP Servlets can be used to generate dynamic HTML content. When you use Servlets to do dynamic content you get the following advantages: ïÆ'Ëœ They‟re faster and cleaner than CGI scripts ïÆ'Ëœ They use a standard API (the Servlets API) ïÆ'Ëœ They provide all the advantages of Java (run on a variety of servers without needing to be rewritten). Attractiveness of Servlets: There are many features of Servlets that make them easy and attractive to use. These include: ïÆ'Ëœ Easily configured using the GUI-based Admin tool ïÆ'Ëœ Can be loaded and invoked from a local disk or remotely across the network. ïÆ'Ëœ Can be linked together, or chained, so that one Servlets can call another Servlets, or several Servlets in sequence. ïÆ'Ëœ Can be called dynamically from within HTML pages, using server-side include tags. ïÆ'Ëœ Are secure – even when downloading across the network, the Servlets  security model and Servlets sandbox protect your system from unfriendly behavior. Advantages of Servlet API One of the great advantages of the Servlet API is protocol independence. It assumes nothing about: ïÆ'Ëœ The protocol being used to transmit on the net ONLINE LIBRARY BY M.SATHISH KUMAR Page 41 DOCUMENTATION OF ONLINE LIBRARY July 24, 2012 ïÆ'Ëœ How it is loaded ïÆ'Ëœ The server environment it will be running in ïÆ'Ëœ These qualities are important, because it allows the Servlet API to be  embedded in many different kinds of servers. There are other advantages to the Servlet API as well. These include: ïÆ'Ëœ It‟s extensible – you can inherit all your functionality from the base classes made available to you. ïÆ'Ëœ it’s simple, small, and easy to use. Features of Servlets: ïÆ'Ëœ Servlets are persistent. Servlet are loaded only by the web server and can maintain services between requests. ïÆ'Ëœ Servlets are fast. Since Servlets only need to be loaded once, they offer much better performance over their CGI counterparts. ïÆ'Ëœ Servlets are platform independent. ïÆ'Ëœ Servlets are extensible. Java is a robust, object-oriented programming language, which easily can be extended to suit your needs ïÆ'Ëœ Servlets are secure. ïÆ'Ëœ Servlets can be used with a variety of clients. Loading Servlets: Servlets can be loaded from three places From a directory that is on the CLASSPATH. The CLASSPATH of classes reside. From the

What Does the French Word Génial Mean in English

You might find yourself using the French word gà ©nial in a variety of situations. Gà ©nial is an adjective and is often used in informal conversations to express happiness. Definitions and Examples gà ©nial (adjective): of genius, inspired Cest une gà ©niale idà ©e !Thats a  brilliant idea!   gà ©nial (adjective, informal): great, cool Ce film est gà ©nial.This movie is great.  On  va  au  resto. - Gà ©nial !Were going to a restaurant. - Great! Pronunciation The word gà ©nial is pronounced [zhay nyal].