Cannot insert explicit value for identity column in table 'table' when IDENTITY_INSERT is set to OFF

Question

I have the below error when I execute the following script. What is the error about, and how it can be resolved?

Insert table(OperationID,OpDescription,Filte         


        

Answer 1

There are basically 2 different ways to INSERT records without having an error:

1) When the IDENTITY_INSERT is set OFF. The PRIMARY KEY "ID" MUST NOT BE PRESENT

2) When the IDENTITY_INSERT is set ON. The PRIMARY KEY "ID" MUST BE PRESENT

As per the following example from the same Table created with an IDENTITY PRIMARY KEY:

CREATE TABLE [dbo].[Persons] (    
    ID INT IDENTITY(1,1) PRIMARY KEY,
    LastName VARCHAR(40) NOT NULL,
    FirstName VARCHAR(40)
);

1) In the first example, you can insert new records into the table without getting an error when the IDENTITY_INSERT is OFF. The PRIMARY KEY "ID" MUST NOT BE PRESENT from the "INSERT INTO" Statements and a unique ID value will be added automatically:. If the ID is present from the INSERT in this case, you will get the error "Cannot insert explicit value for identify column in table..."

SET IDENTITY_INSERT [dbo].[Persons] OFF;
INSERT INTO [dbo].[Persons] (FirstName,LastName)
VALUES ('JANE','DOE'); 
INSERT INTO Persons (FirstName,LastName) 
VALUES ('JOE','BROWN');

OUTPUT of TABLE [dbo].[Persons] will be:

ID    LastName   FirstName
1     DOE        Jane
2     BROWN      JOE

2) In the Second example, you can insert new records into the table without getting an error when the IDENTITY_INSERT is ON. The PRIMARY KEY "ID" MUST BE PRESENT from the "INSERT INTO" Statements as long as the ID value does not already exist: If the ID is NOT present from the INSERT in this case, you will get the error "Explicit value must be specified for identity column table..."

SET IDENTITY_INSERT [dbo].[Persons] ON;
INSERT INTO [dbo].[Persons] (ID,FirstName,LastName)
VALUES (5,'JOHN','WHITE'); 
INSERT INTO [dbo].[Persons] (ID,FirstName,LastName)
VALUES (3,'JACK','BLACK'); 

OUTPUT of TABLE [dbo].[Persons] will be:

ID    LastName   FirstName
1     DOE        Jane
2     BROWN      JOE
3     BLACK      JACK
5     WHITE      JOHN