The Structured Query Language (SQL) is a
largely standardized language, which is used for accessing relational
databases. It can be divided as follows:
Data Manipulation Language (DML)
These statements are for reading and changing data in
database tables.
Data Definition Language (DDL)
These statements are for creating and administering database
tables.
Data Control Language (DCL)
These statements are used for authorization and consistency
checks.
Here, each database has a programming interface. This
programming interface allows the user to access the database tables by using
SQL statements. But, these SQL statements in the programming interfaces are not
fully standardized. So, you must refer to the documentation of that system for
a list of the SQL statements available and also their correct syntax in order
to access a specific database system.