Necessary Definition of Database

1. Database Management System :  Interrelated data and a sets of program by which we can access and manipulate those data is called Data Management System.
2. Data: Data is sequence of digit. data is those elements which will be information after processed.

there are three type of data
such as i)      Numeric
            ii)         Textual

iii)                 Graphical

3. Information : information is processed data.
4. Data structure : Organized Collection of data and a set of operation on them is called data structure.
5. File : If we think a unit of interrelated information or records is called file.
6. Database : All structured data of a organization store in a computer system is called database.

There are four kinds of database

I)                   Hierarchical DBMS

II)                 Network DBMS

III)              Relational DBMS

IV)              Inverted DBMS

7. Database Integrity: if data are interconnected with each other in the database is called data integrity.
8.  Database redundancy : If homologues data are stayed in defferent place in the database is called database redundancy.
9. Data Model : Data Model is a collection of same conceptual tools which describe data, data relationship, data semantics, and data constraints. data Model is main base of data structured.

 There are three types of data Model

I)                   Object based logical model

II)                 record base Logical Model.

III)              Physical Model

10.   Relational Data Model: the Data Model  which use some table to express relation among data of record base logical model
11. Data Schema : Overall design of database is called database schema
12. Data Dictionary: After Compilation of data definition language we get a set of table. Those are stored in a file. This file is called data dictionary.
13. Data Entity : Data Entity is some objects which has existence ad we can distinguish them form each other.
14. Entity set : a Group of similar object which has similar properties.
15. Primary key : An unique  identifier which identify the entity differently is called primary key.
16. Formal Query Language : Formal Query Language is a language by which we can get procedural or non procedural benefit.
17. Commercial Query Language: Commercial  Query Language is a language by which we can get procedural and non procedural benifit.
18. Most Popular Query Language are:

I)                   SQL ( Structured Query Language)

II)                 QBE ( Query By Example)

III)              Quel ( ( Query Language)

IV)              Datalog.

19. Several Parts of SQL

I)                   DDL (Data definition Language)

II)                 DML ( Data Manipulation Language)

III)              Embeded DML

IV)              View Definition

V)                Authorization

VI)              Integrity

VII)           Transaction Control

20.  There are three clause of SQL

I)                   select

II)                 from

III)              where

21. Aggregate function of SQL

I)                   average : avg

II)                 minimum : min

III)              Maximum: Max

IV)              Total : SUM

V)                Count : Count

  Server Database System : in this system data are stored centrally. this central computer is call server. This system is called client server system.

22. Parallel Database system
23. Distributed Database System