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MySQL Database	3.2 ALTER TABLE ...

Changing a Constraint

You can use the ALTER TABLE statement to change existing constraints.

ALTER TABLE hotel.customer ALTER CONSTRAINT cno_cons CHECK cno > 0

For the customer table, the cno_cons constraint has changed. The customer number must be greater than 0.

Dropping a Constraint

You can use the ALTER TABLE statement to drop a constraint.

ALTER TABLE hotel.reservation DROP CONSTRAINT staying

dev.mysql.com/doc/maxdb/en/94/38a04028f40160e10000000a1550b0/content.htm↑

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See also:

• create table online
• dev.mysql.com/doc/mysql/en/alter-table.html↑

<- 3.1 Create Table       3.2.1 Change Constraint ->

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