You can add a new constraint by using the ADD CONSTRAINT clause.
By default, the index created when you add PRIMARY KEY constraints is created in ascending order, and you can define the key sorting order by specifying the ASC or DESC keyword next to the column name.
ALTER [ TABLE | CLASS | VCLASS | VIEW ] table_name
ADD CONSTRAINT < constraint_name > column_constraint ( column_name_comma_list )
column_constraint ::=
UNIQUE [ KEY ] |
PRIMARY KEY |
FOREIGN KEY [ <foreign_key_name> ] REFERENCES [referenced_table_name]( column_name_comma_list )
[ <referential_triggered_action> ... ]
<referential_triggered_action> ::=
{ ON UPDATE <referential_action> } |
{ ON DELETE <referential_action> } |
{ ON CACHE OBJECT cache_object_column_name }
<referential_action> ::=
CASCADE | RESTRICT | NO ACTION | SET NULL
ALTER TABLE a_tbl ADD CONSTRAINT PRIMARY KEY(id);
ALTER TABLE a_tbl ADD CONSTRAINT PRIMARY KEY(id, no DESC);
ALTER TABLE a_tbl ADD CONSTRAINT UNIQUE u_key1(id);