about Triggers ?

Question

good morning ih vae a firebird database in c# i have 2 tables patients and consultations i want create trigger block delete if patient have consultation so if code_pat in consultations table thank you good day

Bikesh Srivastava · Answer

Hi you don't need to create triggeryou can use merge query to resolve your problem. https://bikeshsrivastava.blogspot.in/2016/07/part-28-what-is-merge-query-in-sql.html

Nitin Sontakke · Answer

Why not just create a foreign key constraint which will automatically restrict the deletion and you (hopefully) will also get a trappable exception which you can convert into a use friendly message.

dzconception · Answer

this triger is writen in sqlserver i want it in firbird please ?

Rajeev Punhani · Answer

Hi CREATE TRIGGER [dbo].[patient_InsteadOfDELETE] ON [dbo].[patient] INSTEAD OF DELETE AS BEGIN SET NOCOUNT ON ; DECLARE @patientid INT SELECT @patientid=DELETED.patientid FROM DELETED IF( select count (*) from consultations where code_pat=@patientid2>0) BEGIN RAISERROR( 'Recordcannotbedeleted' 161) ROLLBACK END ELSE BEGIN DELETE FROM patient WHERE PatientId=@patientid END END please use the column namesbased on your table.

dzconception · Answer

thank yoy again but i have probleme with this code in firebird on declare SET TERM ^ ; CREATE TRIGGER TRIGGER01 FOR PATIENTS ACTIVE BEFORE DELETE POSITION 0 AS BEGIN SETNOCOUNTON DECLARE VARIABLE patientid INTEGER begin SELECT patientid=DELETED.patientid FROMDELETED IF(selectcount(*)fromconsultationswherecode_pat=@patientid2>0) BEGIN RAISERROR( 'Recordcannotbedeleted' 161) ROLLBACK END ELSE BEGIN DELETEFROMpatient WHEREPatientId=@patientid END END end ^ SET TERM ; ^

Rajeev Punhani · Answer

Hi Please see the below link http://www.aspsnippets.com/Articles/SQL-Server-Instead-Of-Delete-Trigger-Example.aspx