Let us go through the most important categories of Structured Query Language. It is also known as SQL.
SQL - Structured Query Language
SQL have several categories of commands. But, the most important categories are nothing but to create tables, manipulate data in tables and read data from tables.
- DDL - Data Definition Language
- DML - Data Manipulation Language
- DQL - Data Query Language
There are other categories as well, such as TCL where we have commands to commit or revert/rollback changes to the database objects.
DDL - Data Definition Language
Here is the DDL Command to create a table.
CREATE TABLE orders ( order_id INTEGER, order_date DATE, order_customer_id INTEGER, order_status VARCHAR2(30) );
DML - Data Manipulation Language
Here is the example to get data into a table.
INSERT INTO orders VALUES (1, sysdate, 100, 'COMPLETE');
DQL - Data Query Language
Here is the command to query data from a table.
SELECT * FROM orders;