Can we truncate table with foreign key?

As per mysql documentation, TRUNCATE cannot be used on tables with foreign key relationships. There is no complete alternative AFAIK. Dropping the contraint still does not invoke the ON DELETE and ON UPDATE.

Does truncate ignore foreign keys?

The only way is to drop foreign keys before doing the truncate. And after truncating the data, you must re-create the indexes.

Does truncate lock table MySQL?

2 Answers. You can’t truncate a table that is locked for writing. This is because “truncate” means “destroy the table, and recreate a new one with the same schema.”

What does truncate table do in MySQL?

TRUNCATE TABLE empties a table completely. It requires the DROP privilege. Logically, TRUNCATE TABLE is similar to a DELETE statement that deletes all rows, or a sequence of DROP TABLE and CREATE TABLE statements. To achieve high performance, it bypasses the DML method of deleting data.

Can we truncate a table with primary key?

To delete data from a table referenced by a foreign key constraint, you cannot use the TRUNCATE TABLE statement. In this case, you must use the DELETE statement instead. It is not the case for the DELETE statement.

How do I truncate all tables in a database?

A solution that can TRUNCATE all tables

1. Create a table variable to store the constraint drop and creation scripts for the database.
2. Load the data for all tables in the database.
3. Execute a cursor to drop all constraints.
4. Truncate all tables.
5. Recreate all the constraints.

Can we drop a table which has primary key?

You can delete (drop) a primary key in SQL Server by using SQL Server Management Studio or Transact-SQL. When the primary key is deleted, the corresponding index is deleted.

How do you TRUNCATE a table with a foreign key constraint?

You can’t truncate a table that has a foreign key constraint, that is the whole reason for having a constraint. You will need to delete and re-create the constraints so make sure you script them out before deleting them.

How do I TRUNCATE a table in MySQL workbench?

Here is the basic syntax of the TRUNCATE TABLE statement:

1. TRUNCATE [TABLE] table_name;
2. CREATE TABLE books ( id INT AUTO_INCREMENT PRIMARY KEY, title VARCHAR(255) NOT NULL ) ENGINE=INNODB;
3. CALL load_book_data(10000);
4. SELECT * FROM books;
5. TRUNCATE TABLE books;

How do you truncate a table with a foreign key constraint?

Does MySQL support foreign keys?

MySQL supports foreign keys, which permit cross-referencing related data across tables, and foreign key constraints, which help keep the related data consistent.

Does truncate drop and recreate table?

TRUNCATE TABLE keeps all of your old indexing and whatnot. DROP TABLE would, obviously, get rid of the table and require you to recreate it later. Drop gets rid of the table completely, removing the definition as well. Truncate empties the table but does not get rid of the definition.

How to create foreign key in MySQL?

MySQL Foreign Key Introduction to MySQL foreign key. A foreign key is a column or group of columns in a table that links to a column or group of columns in another table. MySQL FOREIGN KEY syntax. MySQL FOREIGN KEY examples. Drop MySQL foreign key constraints. Disabling foreign key checks.

Can table have two foreign keys?

A table can have multiple foreign keys and no composite keys. A composite key simply means that there are two or more columns making up the key value. The set of columns in a foreign key references the values in a set of columns in another table (or, exceptionally, of another set of columns in the same table).

What is a FOREIGN KEY constraint in MySQL?

A foreign key is a field in a table that matches a field of another table. A foreign key places constraints on data in the related tables that, which enables MySQL to maintain referential integrity.