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18 wrz 2008 · I have created a foreign key (in SQL Server) by: alter table company add CountryID varchar(3); alter table company add constraint Company_CountryID_FK foreign key(CountryID) references Country; I then run this query: alter table company drop column CountryID; and I get this error:
1 paź 2008 · Right click the table design and go to Relationships and choose the foreign key on the left-side pane and in the right-side pane, set Enforce foreign key constraint to 'Yes' (to enable foreign key constraints) or 'No' (to disable it).
The FK.is_disabled holds the "Enforce Foreign Key Constraint" attribute and it should add a second alter for FKs with FK.is_disabled=0 that disables the FK (ALTER TABLE <mytable> NOCHECK CONSTRAINT <myconstraint>).
You can delete a foreign key constraint in SQL Server by using SQL Server Management Studio or Transact-SQL. Deleting a foreign key constraint removes the requirement to enforce referential integrity. Foreign keys reference keys in other tables, for more information, see Primary and Foreign Key Constraints.
To delete a foreign key from a table, use the ALTER TABLE clause with the name of the table (in our example, student) followed by the clause DROP CONSTRAINT with the name of the foreign key constraint. In our example, the name of this constraint is fk_student_city_id.
3 mar 2023 · You can disable a foreign key constraint during INSERT and UPDATE transactions in SQL Server by using SQL Server Management Studio or Transact-SQL. Use this option if you know that new data will not violate the existing constraint or if the constraint applies only to the data already in the database.
The FOREIGN KEY constraint prevents invalid data from being inserted into the foreign key column, because it has to be one of the values contained in the parent table.
