SQL Introduction

 SQL

SQL:- SQL stands for Structured Query Language. It is used for creating database objects, storing data, manipulating data and retrieving relational data from RDBMS.

         SQL is Quey Language means "Command based language". SQL don't have procedural capabilities  like iteration,looping and decision making .

Below are the basic term used in RDBMS

1) Database :- Database is a collection of schemas.We can create more than databases on same server.

2) Objects :-  Objects can be created by CREATE command. Objects are the
                        basic elements of database.
                        Example :- Below are the Oracle Objects
                        1) Table
                        2) View
                        3) Synonym
                        4) Sequence
                        5) Index
                        6) Function
                        7) Procedure
                        8) Package
                        9) Trigger
 
2) Schema :-  Collection of objects under one user is called its schema.
                       Example:- SCOTT Schema, HR Schema

3) Instance :- Instance is a memory architecture of Oracle Database.It is also
                        known as SGA (System Global Area). More than one databases
                        can be configured under one instance.

4) RDBMS :- RDBMS is a software which can manage relation database.

5) Transaction :- Collection set of statements between login to TCL command
                             or between any two TCL commands.

6) Table:-Table is the basic unit for storing data. Table is a structure with
                collection of columns.