Sometimes we need to add ulterior constraints to the table we define. The ALTER TABLE statement enables us to do this. There are several types of constraints we can add. If we want to ensure that all ...

create table t1_2 partition of t1 for values in ( 2 ); create unique index ix1 on t1 ( id, doy ); alter table t1 add constraint pk_t1 primary key using index ix1; ERROR: ALTER TABLE / ADD CONSTRAINT ...

Adding a primary key using alter command:alter command is generally used to modify table . it can be used to add columns or to remove columns. using alter command we can also add or remove a key from ...

Referential constraints are optional and can be defined in CREATE TABLE statements and ALTER TABLE statements. Referential constraints are enforced by the database manager during the execution of ...