Database Management Systems Book 4th Edition

Here is another book from information technology for all of you Database Management System 4th Edition

What is Database Management System(DBMS) ?

DBMS is Database Management System.Its is used for Creating and Maintaining all the computer or digital database.SQL (Structured Query Language) is used as a DBMS language.In short :DBMSA database management system (DBMS) is system software for creating and managing databases. TheDBMS provides users and programmers with a systematic way to create, retrieve, update and manage data.UseThese are systems that can be used to manage transactional databases, such as HR systems, banking systems and so on.


 These are typically optimized for performing transactions.Types of DBMS languagesData Definition Language (DDL) : Statements are used to define the database structure or schema. Some examples: CREATE - to create objects in the databaseALTER - alters the structure of the databaseDROP - delete objects from the databaseTRUNCATE - remove all records from a table, including all spaces allocated for the records are removedCOMMENT - add comments to the data dictionaryRENAME - rename an objectData Manipulation Language (DML) : Statements are used for managing data within schema objects. Some examples: SELECT - Retrieve data from the a databaseINSERT - Insert data into a tableUPDATE - Updates existing data within a tableDELETE - deletes all records from a table, the space for the records remainMERGE - UPSERT operation (insert or update)CALL - Call a PL/SQL or Java subprogramEXPLAIN PLAN - explain access path to dataLOCK TABLE - control concurrencyData Control Language (DCL) Some examples: GRANT - gives user's access privileges to databaseREVOKE - withdraw access privileges given with the GRANT commandTransaction Control (TCL) : Statements are used to manage the changes made by DML statements. It allows statements to be grouped together into logical transactions. Some examples: COMMIT - save work doneSAVEPOINT - identify a point in a transaction to which you can later roll backROLLBACK - restore database to original since the last COMMITSET TRANSACTION - Change transaction options like isolation level and what rollback segment to useUses of DBMSBasically the only use of DBMS is as the name says to manage a database system. Wherever and in whatever application you need to manage a database, you uses a DBMS. One case scenario of how DBMS is used are:Banking: Banks store customer data, trabsaction data and all other kind of data for which they need to use a database and a DBMS to access that database. Whenever a bank employ or a bank customer uses bank website to access this data, request if passed to server and DBMS is used to retrieve the required data from the databaseTelecommunications:



For keeping records of calls made, generating monthly bills, maintaining balances on prepaid calling cards and storing information about the communication networks.Manufacturing: For management of supply chain and for tracking production of items in factories, inventories of items in warehouses/stores and orders for items.Web based services: Almost all non static websites and web services uses a database and they also need a DBMS to access this database and data.


DBMS LanguagesSQL: Structured Query Language is one of the language which is used by many database management systems for example, Oracle SQL, MS-SQL, MySQL, Postgre SQL.SQL statements used commonly can be categorized as data definition language (DDL), data control language (DCL) and data manipulation language (DML)

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