Objectives: Introduction Over View of System Analysis and Design



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ms-04

Method

Advantages

Disadvantages

Sequential Simple to design. Records cannot be Easy to program. added to middle of file. Variable length & blocked records available Best use of software space Indexed sequential Records can be inserted or Unique keys required Updated in middle of file. Processing Processing maybe carried occasionally slow. out Sequentially or randomly Periodic reorganization of file required. Inverted list Used in applications requesting specific data on multiple keys. My address is 38, Sector 2
Relative Address
My relative address is the 4
th house on left from community center.
Absolute Address

Random Records can be inserted or Calculating address updated in middle of file required for Better control over record processing. Allocation. Variable- length records nearly impossible to process.



7.4 Data Base Design
A decade ago, database was unique to large corporations with mainframes. Today it is recognized as standard of MIS and is available for virtually every size of computer. Before the database concept became operational, users had programs the handled their own data independent of other users. It was a conventional file environment with no data integration or sharing of common data across applications. Ina database environment, common data are available and used by several users. Instead of each program (or user) managing its own data, data across applications are shared by authorized users with the database software managing the data as an entity. A program now requests data through the database management system (DBMS, which determines data sharing.

7.4.1 Objectives of Data Base
The general theme behind a database is to handle information as an integrated whole. There is none of the artificiality that is normally embedded in separate file or applications. A database is a collection of interrelated data stored with minimum redundancy to serve many users quickly and efficiently. The general objective is to make information access easy, quick, inexpensive and flexible for the user. In database design, several specific objectives are considered
1.

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