Alter table command, ALTER TABLE Command : This command is used for variation of existing, Database Management System

Alter table command, Database Management System

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ALTER TABLE Command: This command is used for variation of existing structure of the table in the given situation:

When a new column is to be added to the table structure.
When the existing column definition has to be altered, i.e., changing the width of the data type or the data type itself.
When integrity constraints have to be dropped or included.
When a constraint has to be allowed or not allowed.

Syntax

ALTER TABLE

ADD ( ...); ALTER TABLE

MODIFY ( ...);

ALTER TABLE

ADD CONSTRAINT < constraint type>(field name);

ALTER TABLE

DROP;

ALTER TABLE

ENABLE/DISABLE ;

You require to put many constraints like that the database integrity is not compromised.

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Alter table command, Database Management System

Related Discussions:- Alter table command

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