SQL Structured Query Language or Standard Query Language

SQL is the only language through which you can access database.

Advantages of Using SQL

1) Standard Query langauge used by all DBMS.
2) English like Language.
3) Non-procedural language.
4) Batch processing, processes multiple records rather than one at a time.

Sub languages of SQL include the following.
DDL Data Defination Language
Create,Alter,Drop,Rename and Truncate
DML Data Manipulation Language
Select( although belongs to query language),Insert,Update,Delete
DCL Data Control Language
Grant,Revoke
TCL Transaction Control Language
Commit,Rollback,Savepoint and Rollback to Save point
DDL Data Defination Language
Is used for defining all the objects in the database. This contains three commands Create, Alter and Drop.

Create is used for create all the objects in the database. The objects that can be created in the database are Table, views, Indexes, sequences, synonyms.

Table is the primary object that needs to be created prior to creating any other objects in the database. Table is the object, which is used for storing data in the database. All other objects i.e views, indexes, sequences and synonyms are dependent on tables. All the database objects are logical storage objects with are physically mapped to the datafiles.

Tables are storage objects for Data
Views are used for security and are used for storing complex queries
Indexes are used for improving performance of the queries
Synonyms are used for creating shortcuts to database objects
Sequences are used for generating automatic sequencing