MBA Database Management Essay

A1.Differentiate in the midst of conventional File System & Modern Database System File Base arrangement were the traditional placements which has been replaced now by modern infobase dusts. All informationbase masking ar using the Modern day infobase steering systems now a long time . The difference surrounded by the these two technologies given below.File- ground SystemFile-based systems were an early render to computerize the manual filing system. File-based system is a collection of application programs that perform serve ups for the end-users. Each program defines and manages its entropy. However, five figures of problem be occurred in using the file-based onward motionSeparation and isolation of dataWhen data is isolated in spot files, it is much difficult for us to entrance m cardinaly data that should be available. The application programmer is required to synchronize the touch of two or more files to ensure the correct data is extracted. duplicate of dataWhen employing the decentralized file-based approach, the uncontrolled gemination of data is occurred. Uncontrolled duplication of data is undesirable be createi.Duplication is wastefulii.Duplication stooge lead to loss of data integrityData dependenceUsing file-based system, the physical complex body part and w atomic number 18housing of the data files and records argon defined in the application program code. This feature is cognize as program-data dependence. Making changes to an existing structure are preferably difficult and result lead to a modification of program. Such sustainment activities are time-consuming and subject to error.Incompatible file formatsThe structures of the file are dependent on the application programming language. However file structure provided in one programming language such as pick out file, indexed-sequential file which is available in COBOL programming, whitethorn be different from the structure generated by other programming lang uage such as C. The take up incompatibility hurls them difficult to process jointly.Fixed queries / proliferation of application programsFile-based systems are rattling dependent upon the application programmer. Any required queries or reports generate to be written by the application programmer. Norm whatsoevery, a fixed format inquiry or report crapper only be entertained and no facility for ad-hoc queries if offered. File-based systems also give tremendous pressure on data processing staff, with users complaints on programs that are inadequate or inefficient in meeting their demands. Documentation whitethorn be limited and criminal maintenance of the system is difficult. Provision for security, integrity and recovery capability is very limited.Database SystemsIn beau monde to overcome the limitations of the file-based approach, the concept of database and the Database caution System (DMS) was emerged in 60s. A database is an application that basin store and retrieve d ata very rapidly. The relational potato chip refers to how the data is stored in the database and how it is organized. When we talk about database, we mean a relational database, in fact an Rdatabase management system Relational Database Management System. In a relational database, every last(predicate) data is stored in panels. These have the same structure iterate in each row (like a sp analysesheet) and it is the relations between the tables that make it a relational tableAdvantagesA number of advantages of applying database approach in application system are obtained including Control of data redundancy The database approach attempts to snuff out the redundancy by integrating the file. Although the database approach does non eliminate redundancy entirely, it controls the amount of redundancy inherent in the database.Data agreementBy eliminating or controlling redundancy, the database approach squeezes the risk of inconsistencies occurring. It ensures any copies of the imagination are kept consistent. More information from the same amount of dataWith the integration of the operated data in the database approach, it whitethorn be possible to elicit additional information for the same data.Sharing of dataDatabase belongs to the entire agreement and grass be shared by all authorized users. amend data integrityDatabase integrity provides the validity and consistency of stored data. Integrity is ordinarily expressed in terms of constraints, which are consistency rules that the database is non permitted to violate. alter securityDatabase approach provides a protection of the data from the unauthorized users. It may take the term of user names and passwords to identify user typewrite and their access right in the motion including retrieval, insertion, updating and deletion.Enforcement of standardsThe integration of the database enforces the demand standards including data formats, naming conventions, documentation standards, update procedures an d access rules.Economy of home baseCost savings can be obtained by combining all organizations procedureal data into one database with applications to work on one source of data.Balance of conflicting requirementsBy having a morphological design in the database, the conflicts between users or departments can be resolved. Decisions will be based on the base use of resources for the organization as a whole rather that for an individual entity. meliorate data availableness and responsivenessBy having an integration in the database approach, data accessing can be crossed departmental boundaries. This feature provides more die hardality and better services to the users.increase productivityThe database approach provides all the low-level file-handling routines. The provision of these dish outs allows the programmer to revolve about more on the specific buy the farmality required by the users. The fourth-generation environment provided by the database can simplify the database appl ication development.Improved maintenanceDatabase approach provides a data independence. As a change of data structure in the database will be affect the application program, it simplifies database application maintenance.Increased concurrencyDatabase can manage concurrent data access effectively. It ensures no interference between users that would not result any loss of information nor loss of integrity.Improved backing and recovery servicesModern database perplexity system provides facilities to background the amount of processing that can be lost following a failure by using the transaction approach.DisadvantagesIn split of a large number of advantages can be found in the database approach, it is not without any challenge. The following disadvantages can be found includingComplexityDatabase management system is an extremely complex piece of software. All parties must be familiar with its functionality and take full advantage of it. Therefore, training for the administrators, des igners and users is required.SizeThe database management system consumes a substantial amount of main memory as well as a large number amount of phonograph recording space in order to make it run efficiently.Cost of DBMSA multi-user database management system may be very expensive. level(p) after the installation, there is a high recurrent annual maintenance exist on the software.Cost of conversionWhen moving from a file-base system to a database system, the company is required to have additional expenses on hardware acquisition and training cost.PerformanceAs the database approach is to cater for virtually(prenominal) applications rather than exclusively for a particular one, some applications may not run as fast as before.Higher impact of a failureThe database approach increases the vulnerability of the system due to the centralization. As all users and applications reply on the database availability, the failure of any component can lend operations to a halt and affect th e services to the customer seriouslyQ2. What is the disadvantage of sequential file organization? How do you overcome it? What are the advantages & disadvantages of Dynamic Hashing?Disadvantage of Sequestial file organizationA file that contains records or other elements that are stored in a chronological order based on account number or some other identifying data. In order to locate the desired data, sequential files must be read starting at the beginning of the file. A sequential file may be stored on a sequential access device such as magnetic tape or on a charge access device such as magnetic disk. Contrast with ergodic file.Dynamic HashingAdvantagesThe main advantage of hashisheesheesh tables over other table data structures is speed. This advantage is more apparent when the number of entries is large (thousands or more). Hash tables are particularly efficient when the maximum number of entries can be predicted in advance, so that the bucket array can be allocated once wi th the optimum size and never resized.If the set of attain-value pairs is fixed and known ahead of time (so insertions and deletions are not allowed), one may reduce the average search cost by a careful pickaxe of the hash function, bucket table size, and internal data structures. In particular, one may be able to devise a hash function that is collision-free, or even perfect (see below). In this case the keys need not be stored in the table .DisadvantagesHash tables can be more difficult to implement than self-balancing binary search trees. Choosing an effective hash function for a specific application is more an art than a science. In open-addressed hash tables it is fairly easy to create a poor hash function.Although operations on a hash table take unalterable time on average, the cost of a good hash function can be significantly higher than the inner loop of the lookup algorithm for a sequential list or search tree. so hash tables are not effective when the number of entrie s is very small. (However, in some cases the high cost of computing the hash function can be mitigated by saving the hash value together with the key.)For certain string processing applications, such as spell-checking, hash tables may be less efficient than tries, finite automata, or Judy arrays. Also, if each key is represented by a small enough number of bits, then, rather of a hash table, one may use the key this instant as the index into an array of values. Note that there are no collisions in this case.The entries stored in a hash table can be enumerated efficiently (at constant cost per institution), but only in some pseudo-random order. Therefore, there is no efficient counseling to efficiently locate an entry whose key is nearest to a given key. Listing all n entries in some specific order generally requires a separate sorting step, whose cost is proportional to log(n) per entry. In comparison, ordered search trees have lookup and insertion cost proportional to log(n), but allow purpose the nearest key at about the same cost, and ordered catalogue of all entries at constant cost per entry.If the keys are not stored (because the hash function is collision-free), there may be no easy way to enumerate the keys that are present in the table at any given moment.Although the average cost per operation is constant and fairly small, the cost of a single operation may be quite high. In particular, if the hash table uses dynamic resizing, an insertion or deletion operation may occasionally take time proportional to the number of entries. This may be a serious drawback in real-time or synergetic applications.Hash tables in general exhibit poor locality of originthat is, the data to be accessed is distributed seemingly at random in memory. Because hash tables cause access patterns that jump around, this can trigger microprocessor cache misses that cause long delays. Compact data structures such as arrays, searched with linear search, may be faster if the table is relatively small and keys are integers or other short strings. According to Moores Law, cache sizes are ontogeny exponentially and so what is considered small may be increasing. The optimal mental process point varies from system to system.Hash tables become quite inefficient when there are many collisions. While extremely uneven hash distributions are extremely unlikely to arise by chance, a malicious resister with knowledge of the hash function may be able to give information to a hash which creates worst-case behavior by causing overweening collisions, resulting in very poor performance (i.e., a denial of service attack). In critical applications, either universal hashing can be apply or a data structure with better worst-case guarantees may be preferableQ3. What is race type? Explain the difference among a kind instance, relationship type & a relation set?A3.A relationship type R among n entity types E1, E2, , En is a set of associations among entities from thes e types. Actually, R is a set of relationship instances ri where each ri is an n-tuple of entities (e1, e2, , en), and each entity ej in ri is a member of entity type Ej, 1jn. Hence, a relationship type is a mathematical relation on E1, E2, , En, or alternatively it can be defined as a subset of the Cartesian product E1x E2x xEn . Here, entity types E1, E2, , En defines a set of relationship, called relationship sets.Q4. What is SQL? Discuss.Q5. What is ruleization? Discuss various types of Normal Forms? Q6. What do you mean by Shared Lock & Exclusive toss away? Describe briefly two phase locking protocol? MI0034 Database Management System 4 CreditsAssignment Set- 2 (60 Marks)Answer all the QuestionsQ1. Define Data Model & discuss the categories of Data Models? What is the difference between logical data Independence & Physical Data Independence? Q2. What is a B+Trees? Describe the structure of both internal and leaf nodes of a B+Tree? Q3. Describe Projection operation, Set th eoretic operation & join operation? Q4. Discuss Multi Table Queries?Q5. Discuss Transaction affect Concept? 10.2 Describe properties of Transactions? Q6. Describe the advantage of Distributed database? What is Client/ emcee Model? Discuss briefly the security and Internet violation? .