Lecture 01 overview of dbms

Lecture 01 overview of dbms

• 1.
  Database Management SystemIntroduction Database system Hardware Software Data Users Review
• 2.
  Introduction Data Rawfact and figures Example Name, Roll number, invoice no. Information Processed or more useful form of data It helps in decision making process
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  Introduction Information ExampleTime Table, Merit List, Report Card, Marks Need of Information Knowledge Information containing wisdom Derived from fundamental processing and organizing
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  Introduction Difference b/wData and Information
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  Database The relatedinformation when placed in an organized form makes a database Unorganized information has no meaning Example Dictionary Telephone directory Address book Introduction
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  Manual database andits problems Traditional file processing system Limitation of file processing system Database and computers
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  Commonly performed operationson database Insertion : to add new information. e.g. to insert new address in address book. Updation : to modify or edit the existing information. e.g. your friend has shifted a new place so his address would get changed. Deletion : to remove or delete unwanted information e.g. delete unwanted contacts in ur mobile phones
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  retrieval operation : to view or retrieve the stored information. e.g. you have to find address of one of your old friend “abcd” Sort operation : arranging the information in a desired ascending or descending order etc.
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  Building blocks ofa database Columns : columns are similar to fields that is individuals items of data that we wish to store. Rows : rows are similar to records as they contain data of multiple columns. Tables : table is a logical group of columns.
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  Characteristics of databaseOrganized/related Shared Permanent or persistence Validity/integrity/correctness Security Consistency Non-redundancy Independence Easily accessible Recoverable Flexible to change
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  Database system DefinitionDBMS “System that allow users to define, create and maintain a database and provides controlled access to the data.” enable user to store, modify and extract information as per the requirement Intermediate layer
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  Example Computerized LibrarySystem ATM Flight reservation system Railway reservation system etc. DBMS in market Dbase, Foxpro, IMS and Oracle Database system
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  Components of DBMSEnvironment Hardware Software Data Users Procedures Database system
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  Hardware Computer SystemStorage devices Input / Output devices DB work on micro computer to large mainframe Hardware issues Designed system
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  Software Software isactual DBMS b/w physical data and users Requests handled by DBMS Provide simple interface Mediator b/w database and user Utilities (Report writers, application development,design aids etc) Example MS Access, Oracle an IBM DB2
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  Data Most importantcomponent of DBMS Bridge b/w Machine and User
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  Users Different userscan access data Depending on their degree of expertise users are classified in the following groups Naïve Users (ATM user) Online Users Application Programmers Sophisticated Users DBA
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  Advantages of DBMSControlling redundancy Integrity can be enforced Inconsistency can be avoided Data can be shared Standards can be enforced Restricting unauthorized access
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  Solving enterprise requirementthan individual requirement Providing backup and recovery Cost of developing and maintaining system is lower Data model can be developed Concurrency control
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  Disadvantages of DBMSComplexity Size Performance Higher impact of a failure Cost of DBMS Additional hardware costs Cost of conversion
• 21.
  Comparison of filemanagement system with database management system File management Small system Relatively cheep Simple structure Redundant data Chances of inconsistency No security Isolated data Often single user DBMS Large systems Expensive Complex structure Reduced redundancy Consistent Security Data can be shared Multiple users