I have two tables (Parent and Child) containing millions of records. I want to delete some rows (106 rows) from...
By submitting your email address, you agree to receive emails regarding relevant topic offers from TechTarget and its partners. You can withdraw your consent at any time. Contact TechTarget at 275 Grove Street, Newton, MA.
both tables. Which is the best approach to do this? I have dropped a foreign key constraint before deleting rows from Parent. But when I try to add the constraint, it is taking 10 minutes to execute. Could you suggest some other better approach?
The reason it takes so long to add the constraint back is because the database has to check each Child to ensure that the foreign key is valid, and that could be millions of checks.
In my opinion, the best way to do this is with ON DELETE CASCADE. You won't need to drop the foreign key constraint, or add it back afterwards. In fact, it is this constraint which makes the synchronized deletion from both tables possible.
Related Q&A from Rudy Limeback
Read SQL expert Rudy Limeback's advice for counting combinations in a table with SQL's GROUP BY clausecontinue reading
Read an example of an SQL case expression from our SQL expert Rudy Limeback.continue reading
Read about the Mimer Validator, a tool used to verify your SQL code, in this tip from SQL expert Rudy Limeback.continue reading
Have a question for an expert?
Please add a title for your question
Get answers from a TechTarget expert on whatever's puzzling you.