What is a reference constraint SQL Server?
The FOREIGN KEY constraint is used to prevent actions that would destroy links between tables. The table with the foreign key is called the child table, and the table with the primary key is called the referenced or parent table. …
How do I delete a foreign key constraint in a table?
To delete a foreign key constraint
- In Object Explorer, expand the table with the constraint and then expand Keys.
- Right-click the constraint and then click Delete.
- In the Delete Object dialog box, click OK.
Why is the DELETE statement conflicted with the?
The message is pretty explicit: you are trying to delete something which is referenced elsewhere in the database and there is a constraint that you cannot do that to prevent “hanging” references. Probably, what you are trying to delete is a row that is used as a Foreign key in a different table: “User_history”.
Do you remove references from a TRUNCATE statement?
To TRUNCATE you must remove the references. TRUNCATE is a DDL statement (comparable to CREATE and DROP) not a DML statement (like INSERT and DELETE) and doesn’t cause triggers, whether explicit or those associated with references and other constraints, to be fired.
Is the TRUNCATE statement the same as insert and delete?
TRUNCATE is a DDL statement (comparable to CREATE and DROP) not a DML statement (like INSERT and DELETE) and doesn’t cause triggers, whether explicit or those associated with references and other constraints, to be fired. Because of this, the database could be put into an inconsistent state if TRUNCATE was allowed on tables with references.
How to delete a table without changing the references?
To DELETE, without changing the references, you should first delete or otherwise alter (in a manner suitable for your purposes) all relevant rows in other tables. To TRUNCATE you must remove the references.
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