SQL Primer
SQL is Structure Query Language. It is a way of communicating with the DataBase Management System (DBMS). A DBMS has the stored data in a particular format, and has tools that retrieves and manipulates this data. The SQL communicates to the DBMS on what task requires to be done by it.
There are a lot of different DBMS. The earlier ones started of by storing data in simple flat files with each record stuffed in a line and each column of data separated by comma or other ASCII character. Then, they evolved into what are called as RDBMS - relational DBMS. In these databases, the data is organized into tables that have one or more columns. Each record is stored as a row, with each of the data split into the different columns.
The tabular structure forms the basis for many of the SQL instructions. The SQL instructions may be grouped as:
