Contents
What happens when you drop a foreign key?
When you drop a foreign key using the DROP FOREIGN KEY clause of the ALTER TABLE statement, Db2 drops the corresponding referential relationships. (You must have the ALTER privilege on any dependent tables.) The table’s primary index is no longer primary, although it is still a unique index.
Does dropping a table drop foreign keys?
No, this will not drop your table if there are indeed foreign keys referencing it. Select the tables you want to DROP.
How do you add and drop a foreign key?
Dropping Foreign Key Constraints You can drop a foreign key constraint using the following ALTER TABLE syntax: ALTER TABLE tbl_name DROP FOREIGN KEY fk_symbol; If the FOREIGN KEY clause defined a CONSTRAINT name when you created the constraint, you can refer to that name to drop the foreign key constraint.
Does drop table drop constraints?
DROP TABLE always removes any indexes, rules, triggers, and constraints that exist for the target table. However, to drop a table that is referenced by a view or a foreign-key constraint of another table, CASCADE must be specified.
How do you disable a FOREIGN KEY constraint?
To disable a foreign key constraint for INSERT and UPDATE statements In Object Explorer, expand the table with the constraint and then expand the Keys folder. Right-click the constraint and select Modify. In the grid under Table Designer, click Enforce Foreign Key Constraint and select No from the drop-down menu. Click Close.
What happens to foreign key?
A foreign key value may be NULL and indicates a particular record has no parent record. But if a value exists, then it is bound to have an associated value in a parent table. When applying update or delete operations on parent tables there may be different requirements about the effect on associated values in child tables.
How to drop a primary key?
and click Design.
What does foreign key mean?
Foreign Key. Definition – What does Foreign Key mean? A foreign key is a column or group of columns in a relational database table that provides a link between data in two tables. It acts as a cross-reference between tables because it references the primary key of another table, thereby establishing a link between them.