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To turn off foreign key constraint globally, do the following: SET GLOBAL FOREIGN_KEY_CHECKS=0; and remember to set it back when you are done. SET GLOBAL FOREIGN_KEY_CHECKS=1; WARNING: You should only do this when you are doing single user mode maintenance. As it might resulted in data inconsistency.
Unless you disable the foreign key checks, you cannot drop a table referenced by a foreign key constraint. To disable foreign key checks, you set the foreign_key_checks variable to zero as follows: SET foreign_key_checks = 0; Code language: SQL (Structured Query Language) (sql)
If you want to disable a foreign key constraint from a specific table, you can use the following syntax. ALTER TABLE table_name DISABLE KEYS; After completion of the specific work on the table, you can re-enable the Foreign key constraint by the following statement.
20 mar 2015 · Use the following to disable constraints: -- disable UNIQ, PK, ... ALTER TABLE <tablename> DISABLE KEYS; -- diable FK. SET FOREIGN_KEY_CHECKS=0; Check for instance this site for more examples. Restore with: SET FOREIGN_KEY_CHECKS=1; ALTER TABLE <tablename> ENABLE KEYS;
Summary: in this tutorial, you will learn about the MySQL Foreign Key constraint and how to create, drop and disable a foreign key constraint. MySQL Foreign Key Introduction. A foreign key is a column (or set of columns) that establishes a relationship between data in two tables.
8 cze 2021 · We can disable MySQL foreign key constraints by executing: SET FOREIGN_KEY_CHECKS=0; SCRIPT FOR ENABLING:-We can enable MySQL foreign key constraints by executing: SET FOREIGN_KEY_CHECKS=1; To Disable and Enable Global Foreign Key Constraints:-SET GLOBAL FOREIGN_KEY_CHECKS = 0; SET GLOBAL FOREIGN_KEY_CHECKS = 1; EXAMPLE FOR DEMONSTRATION:-Let ...
To disable foreign key checks, you use the following statement: SET foreign_key_checks = 0; Code language: SQL (Structured Query Language) (sql) And you can enable it by using the following statement: SET foreign_key_checks = 1; Code language: SQL (Structured Query Language) (sql)
