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Showing posts with the label important sql commands

SQL Commands

SQL Commands This is a kind of instructions used to communicate with the database. By using sql commands, we can execute set of tasks on a database. Types of sql commands DDL  -   DDL stands for Data Definition Language. This command is used to change schema/structure of a table. These commands can not be roll back. Example: 1. Create - This command is used to create table or database. 2.  Alter - This command is used to update schema in a database. 3. Drop - This command is used to delete schema in a database. 4. Truncate - This command is used to delete rows from the table. DML  -  DML stands for Data Manipulation Language.  This command is used to modify the database. These commands can be roll back. Example: 1. Insert - This command is used to insert data into database. 2. Update - This command is used to update data in a database. 3. Delete - This command is used to delete data in a database. DCL  -  DCL  stands for Data Control Lan...