Asked by: Sandeep Shashwattechnology and computing databases
How do you drop a foreign key?
Last Updated: 31st March, 2020
- In Object Explorer, expand the table with the constraint andthen expand Keys.
- Right-click the constraint and then click Delete.
- In the Delete Object dialog box, click OK.
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In respect to this, can we delete foreign key?
A foreign key with cascade delete meansthat if a record in the parent table is deleted, thenthe corresponding records in the child tablewill automatically be deleted. A foreign keywith cascade delete can be created using either a CREATETABLE statement or an ALTER TABLE statement.
can primary key be null? SQL PRIMARY KEY Constraint. Primary keysmust contain UNIQUE values, and cannot contain NULL values.A table can have only ONE primary key; and in thetable, this primary key can consist of single or multiplecolumns (fields).
Similarly one may ask, what is a foreign key in a database?
A foreign key is a column or group of columns ina relational database table that provides a link betweendata in two tables. It acts as a cross-reference between tablesbecause it references the primary key of another table,thereby establishing a link between them.
Can we drop primary key constraint?
Dropping Primary Keys You cannot drop a primary keyconstraint if another table has a foreign key constraintthat references the primary key. To drop theprimary key, you must first drop all foreignkeys that reference it.