{{parent page="MySQL"}}

==Change a column's definition==
%%(sql)
alter table XXX change COLNAME COLNAME varchar(10);
alter table XXX change COLNAME COLNAME varchar(50) not null;
%%

==Add foreign key constraint==
%%
ALTER TABLE vsusers ADD FOREIGN KEY (sitenum)
REFERENCES vsites (sitenum)
ON UPDATE CASCADE ON DELETE RESTRICT;
%%