SQL Basics Primer

Quite a few people (who are not from the industry I am in) have approached me with the intention of knowing a bit more about SQL. Hence I thought I should put up a basic primer on SQL here as a multi-part (or multi-post) 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:

• Data retrieval tasks
• Data modification tasks
• Data definition tasks
• Control tasks

In the next part of this SQL primer, we will look into the data retrieval statement in SQL - SELECT.
To be continued...