How do I delete a record from my kids table?

How do I delete a record from my kids table?

Two possible approaches.

1. If you have a foreign key, declare it as on-delete-cascade and delete the parent rows older than 30 days. All the child rows will be deleted automatically.
2. Based on your description, it looks like you know the parent rows that you want to delete and need to delete the corresponding child rows.

How do I add cascade delete to a table?

Edit table and columns specification by clicking … as shown in the below image.

1. Select the parent table and the primary key column in the parent table.
2. In the INSERT and UPDATE specifications, select Cascade for the delete rule.
3. Click on Close and save the table in the designer.

Can we delete data from parent without child table?

That means a row in Table A can’t be deleted if any row in Table B references that row. There is no way to get around this except to permanently remove the foreign key. The purpose of a foreign key is to prevent exactly this scenario.

How do you delete rows in tables that contain foreign keys to other tables Oracle?

1-You first need to select rows to delete(in a cursor) 2-Then for each row in the cursor you delete the referencing rows and after that delete the row him self.

Can we delete parent table without deleting child table?

You can’t drop a parent table if you have a child table with a foreign key constraint in place, unless you specify the CASCADE CONSTRAINTS clause: DROP TABLE P CASCADE CONSTRAINTS; This command drops the FK constraint too. Deleting a table will necessarily drop all constraints related to this table.

What is function of on delete cascade?

CASCADE. It is used in conjunction with ON DELETE or ON UPDATE. It means that the child data is either deleted or updated when the parent data is deleted or updated.

What is on delete cascade and on delete set null?

Referential actions include: CASCADE : Delete or update the row from the parent table and automatically delete or update the matching rows in the child table. SET NULL : Delete or update the row from the parent table and set the foreign key column or columns in the child table to NULL .

How does Cascade delete from parent to child?

This should cascade to the parent table and remove the record. Foreign keys only work in the other direction: cascade deletes from parent to child, so when the parent (referenced) record is deleted, any child (referencing) records are also deleted.

When to use on delete cascade in SQL Server?

For this foreign key, we have specified the ON DELETE CASCADE clause which tells SQL Server to delete the corresponding records in the child table when the data in the parent table is deleted. So in this example, if a product_id value is deleted from the products table, the corresponding records in the inventory table…

When to use MySQL on delete Cascade referential action?

However, MySQL provides a more effective way called ON DELETE CASCADE referential action for a foreign key that allows you to delete data from child tables automatically when you delete the data from the parent table. Let’s take a look at an example of using MySQL ON DELETE CASCADE .

How to delete cascade in classicmodels database?

For example, to find tables that associated with the buildings table with the CASCADE deletion rule in the classicmodels database, you use the following query: USE information_schema; SELECT table_name FROM referential_constraints WHERE constraint_schema = ‘classicmodels’ AND referenced_table_name = ‘buildings’ AND delete_rule = ‘CASCADE’