How to delete a row with data with its parent row in another table

Question

There are two tables [UserData] and [HotelData] I\'ve linked them with a foreign key. which is \"Username\" and I want to delete which

Answer 1

There is no need to write any code to delete data on the child table when you delete a record from the UserData table. Just use Cascade delete behavior. It means that if a record in the parent table is deleted, then the corresponding records in the child table will automatically be deleted.

Do the following steps:

1. Open the child table's designer and click Relationships
2. In the opened window and in the Table Designer expand INSERT And UPDATE Specification
3. Change the Delete Rule from No action to Cascade

Like the following image:

Answer 2

The DELETE statement conflicted with the REFERENCE constraint "FKHotelData"

You have a constraint and this is helping with performance, do yourself a favor and add a column IsDeleted with a default value of 0 or to allow null's so it doesn't affect anything.

Then change your SELECT queries to have a WHERE clause that includes the condition

WHERE IsDeleted = 0

The point here is that its a Hotel business and they will want metrics/reporting on bookings. For medical and confidentiality purposes I'd lean toward the cascading delete answers. For this scenario it would be better to logically delete the data instead of physically delete it.

Answer 3

Well. To expand on the other option which isn't exactly ideal, but should be available as well. CASCADE is easier to work with though.

Without that, your best bet is

DELETE FROM HotelData WHERE Username = @Username

Followed by

DELETE FROM UserData WHERE Username = @Username