To disable foreign key constraints when you want to truncate a table: Use FOREIGN_KEY_CHECKS SET FOREIGN_KEY_CHECKS=0; and remember to enable it when you’re done: SET FOREIGN_KEY_CHECKS=1; Or you can use DISABLE KEYS: ALTER TABLE table_name DISABLE KEYS; Again, remember to enable...
本文翻译自:How to temporarily disable a foreign key constraint inMySQL?Is it possible to temporarily disable constraints inMySQL? 是否可以在MySQL中暂时禁用约束?I have two Django models, each with a ForeignKey to the mysql 禁用主键 启用主键 ...
but this is added a) temporarily in best_access_path(), before comparing this scan cost to the best 'ref' access method, and b) permanently by the caller of best_access_path() (@see e.g. best_extension
@table_name)) + ' CHECK CONSTRAINT ALL' AS '--Code to enable the previously disabled constraints' END ELSE BEGIN SELECT 'ALTER TABLE ' + QUOTENAME(@owner) + '.' + QUOTENAME(COALESCE(@target_table, @table_name)) + ' CHECK
• If you have UNIQUE constraints on secondary keys, you can speed up table imports by temporarily turning off the uniqueness checks during the import session: SETunique_checks=0; ... SQL import statements ...SETunique_checks=1; For big tables, this saves a lot of disk I/O because Inn...
Run ndb_restore --allow-pk-changes (possibly along with --ignore-extended-pk-updates, --disable-indexes, and possibly other options as needed) to restore all data Run ndb_restore --rebuild-indexes using the backup made with the desired schema, to rebuild indexes and constraints When extend...
The solution is to run the missing CREATE TABLE and try again or temporarily disable foreign-key-checks. It is essential to perform this stepduring backup restorationsin which circular references may be present. Run the following code to fix the error: ...
They are also used in NDB Cluster to handle uniqueness constraints. Currently, the only partitioning algorithm is hashing and ordered indexes are local to each node. Thus, ordered indexes cannot be used to handle uniqueness constraints in the general case. ...
Temporarily disabling referential constraints (set FOREIGN_KEY_CHECKS to 0) is useful when you need to re-create the tables and load data in any parent-child order. Without this option, it may require a lot of effort to define the correct parent-child order especially if you have a lot ...
InnoDB Notes * Renaming of columns in a parent foreign key is temporarily disabled due to ongoing work on foreign key locking. This restriction will be lifted in MySQL 8.0.4. (Bug #26334071) References: See also: Bug #26659110. Optimizer Notes * The optimizer now supports a SET_VAR hint...