Question

I have two table masterTbl and detailTbl which structure is given below…

--PRIMARY TABLE
CREATE TABLE masterTbl (
id INT IDENTITY(1,1) CONSTRAINT pk_id PRIMARY KEY, 
name VARCHAR(100) NOT NULL, 
description VARCHAR(max))

--FORIGN TABLE
CREATE TABLE detailTbl (
id INT IDENTITY(1,1) PRIMARY KEY,
m_id INT NOT NULL CONSTRAINT fk_mid FOREIGN KEY REFERENCES masterTbl(id) ON DELETE CASCADE,
details VARCHAR(MAX))

I want to perform

TRUNCATE TABLE masterTbl 

but it is encountering error “Cannot truncate table ‘testDB.dbo.masterTbl’ because it is being referenced by a FOREIGN KEY constraint.”

How can i use TRUNCATE command on masterTbl??

Answer 1

You have to remove the FK constraint fk_mid.
But you won’t be able to put it back if the FK Constraint is not respected, cause the CASCADE REMOVE won’t happen (risk of orphans)

Or use DELETE instead of TRUNCATE.
Which will preserve the DELETE CASCADE behaviour.

EDIT

DELETE FROM dbo.masterTbl;
DBCC CHECKIDENT ('dbo.masterTbl', RESEED, 0) -- will set IDENTITY count back to 0