What is SQL? – Structured Query Language (SQL) Explained – AWS

Relational database management systems use structured query language (SQL) to store and manage data. The system stores multiple database tables that relate to each other. MS SQL Server, MySQL, or MS Access are examples of relational database management systems. The following are the components of such a system. 

SQL table

A SQL table is the basic element of a relational database. The SQL database table consists of rows and columns. Database engineers create relationships between multiple database tables to optimize data storage space.

For example, the database engineer creates a SQL table for products in a store: 

Product ID

Product Name

Color ID

0001

Mattress

Color 1

0002

Pillow

Color 2

Then the database engineer links the product table to the color table with the Color ID:

Color ID

Color Name

Color 1

Blue

Color 2

Red

SQL statements

SQL statements, or SQL queries, are valid instructions that relational database management systems understand. Software developers build SQL statements by using different SQL language elements. SQL language elements are components such as identifiers, variables, and search conditions that form a correct SQL statement.

For example, the following SQL statement uses a SQL INSERT command to store Mattress Brand A, priced $499, into a table named Mattress_table, with column names brand_name and cost:

INSERT INTO Mattress_table (brand_name, cost)

VALUES(‘A’,’499’);

Stored procedures

Stored procedures are a collection of one or more SQL statements stored in the relational database. Software developers use stored procedures to improve efficiency and performance. For example, they can create a stored procedure for updating sales tables instead of writing the same SQL statement in different applications.