How can Handel Delete from Table have a relationship with another Table

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i have two tables

&
First Table :

GuestId    Name     Delete
1            Magdy    Delete
2            Rana     Delete
3            Yousf    Delete

Second Table :

Bookingid  GuestId           Place
1             1              Paris     Delete
2             1              Amedica   Delete
3             1              Romanya   Delete

there are relations between 2 tables
Guest 1 --> Have 3 Booking
but
Guest 2 -->Haven't any book (its easy to delete)

please
when i want delete any row in Second table its no problem
but
when i want to delete row from first table & this row have booking in second table
i want to tell me that (you cant Delete this Row, you Must delete all booking at first)

any one can help me please

Posted 30-Nov-13 10:38am

radals

Updated 30-Nov-13 11:14am

Nelek

v2

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Jean-Claude ADIBA · Answer 1 · 2013-11-30T10:51:00

Solution 1

Hi yes of course if you want to delete row in the First Table you Must delete all related rows in the second Table.

But in sql server you can activate cascade delete on the foreign key

Posted 30-Nov-13 10:51am

Jean-Claude ADIBA

Comments

radals 30-Nov-13 23:21pm

can u give me more details what u mean

Jean-Claude ADIBA 30-Nov-13 23:27pm

what laguage do you want to use to delete the data in your two table ?

radals 1-Dec-13 2:52am

C# , Asp.net & Sql server

Jean-Claude ADIBA 1-Dec-13 3:27am

OK AS I TRY TO EXPLAIN YOU LATER, TO DELETE RELATED DATA IN YOUR SQLSERVER DATABASE YOU HAVE 2 SOLUTIONS

1. IN SQLSERVER ADD -ON DELETE CASCADE-STATEMENT TO YOUR FOREIGN KEY GuestId IN BOOKING TABLE BY USING SQL LANGAGE OR YOU CAN USE SQLMANAMENT STUDIO TO ADD IT WITH THE DESIGNER

ALTER TABLE [Booking] ADD CONSTRAINT FK_Booking_Guest_GuestId FOREIGN KEY( GuestId)
REFERENCES [Guest] ( GuestId)
ON DELETE CASCADE;

-ON DELETE CASCADE- PERMIT YOU TO DELETE AUTOMATICALY ALL RELATED ROWS IN BOOKING TABLE WHEN YOU DELETE THE GUEST.

BUT YOU CAN DO IT MANUALLY.

2. IN C# BEFORE DELETE A GUEST ROW.
- COUNT THE ROWS IN BOOKING TABLE WHICH HAVE THE ID OF THE GUEST ROWS YOU WANT TO DELETE
- IF COUNT >0 DELETE ALL THE DATA IN BOOKING TABLE WHICH HAVE THE ID OF THE GUEST ROWS YOU WANT TO DELETE
- NOW YOU CAN DELETE THEN GUEST ROW