Keep identity values when bulk importing data (SQL Server)

Άρθρο
04/04/2023

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW)

Data files that contain identity values can be bulk imported into an instance of Microsoft SQL Server. By default, the values for the identity column in the data file that is imported are ignored and SQL Server assigns unique values automatically. The unique values are based on the seed and increment values that are specified during table creation.

If the data file does not contain values for the identifier column in the table, use a format file to specify that the identifier column in the table should be skipped when importing data. See Use a Format File to Skip a Table Column (SQL Server) for additional information.

Outline
Keep Identity Values Example Test Conditions ● Sample Table ● Sample Data File ● Sample Non-XML Format File Examples ● Using bcp and Keeping Identity Values without a Format File ● Using bcp and Keeping Identity Values with a Non-XML Format File ● Using bcp and Generated Identity Values without a Format File ● Using bcp and Generated Identity Values with a Non-XML Format File ● Using BULK INSERT and Keeping Identity Values without a Format File ● Using BULK INSERT and Keeping Identity Values with a Non-XML Format File ● Using BULK INSERT and Generated Identity Values without a Format File ● Using BULK INSERT and Generated Identity Values with a Non-XML Format File ● Using OPENROWSET and Keeping Identity Values with a Non-XML Format File ● Using OPENROWSET and Generated Identity Values with a Non-XML Format File

Outline

Keep Identity Values

To prevent SQL Server from assigning identity values while bulk importing data rows into a table, use the appropriate keep-identity command qualifier. When you specify a keep-identity qualifier, SQL Server uses the identity values in the data file. These qualifiers are as follows:

Command	Keep-identity qualifier	Qualifier type
bcp	-E	Switch
BULK INSERT	KEEPIDENTITY	Argument
INSERT ... SELECT * FROM OPENROWSET(BULK...)	KEEPIDENTITY	Table hint

For more information, see bcp Utility, BULK INSERT (Transact-SQL), OPENROWSET (Transact-SQL), INSERT (Transact-SQL), SELECT (Transact-SQL), and Table Hints (Transact-SQL).

Note

To create an automatically incrementing number that can be used in multiple tables or that can be called from applications without referencing any table, see Sequence Numbers.

Example Test Conditions

The examples in this topic are based on the table, data file, and format file defined below.

Sample Table

The script below creates a test database and a table named myIdentity. Execute the following Transact-SQL in Microsoft SQL Server Management Studio (SSMS):

CREATE DATABASE TestDatabase;
GO

USE TestDatabase;
CREATE TABLE dbo.myIdentity ( 
   PersonID smallint IDENTITY(1,1) NOT NULL,
   FirstName varchar(25) NOT NULL,
   LastName varchar(30) NOT NULL,
   BirthDate date
   );

Sample Data File

Using Notepad, create an empty file D:\BCP\myIdentity.bcp and insert the data below.

3,Anthony,Grosse,1980-02-23
2,Alica,Fatnowna,1963-11-14
1,Stella,Rosenhain,1992-03-02
4,Miller,Dylan,1954-01-05

Alternatively, you can execute the following PowerShell script to create and populate the data file:

cls
# revise directory as desired
$dir = 'D:\BCP\';

$bcpFile = $dir + 'myIdentity.bcp';

# Confirm directory exists
IF ((Test-Path -Path $dir) -eq 0)
{
    Write-Host "The path $dir does not exist; please create or modify the directory.";
    RETURN;
};

# clear content, will error if file does not exist, can be ignored
Clear-Content -Path $bcpFile -ErrorAction SilentlyContinue;

# Add data
Add-Content -Path $bcpFile -Value '3,Anthony,Grosse,1980-02-23';
Add-Content -Path $bcpFile -Value '2,Alica,Fatnowna,1963-11-14';
Add-Content -Path $bcpFile -Value '1,Stella,Rosenhain,1992-03-02';
Add-Content -Path $bcpFile -Value '4,Miller,Dylan,1954-01-05';

#Review content
Get-Content -Path $bcpFile;
Invoke-Item $bcpFile;

Sample Non-XML Format File

SQL Server support two types of format file: non-XML format and XML format. The non-XML format is the original format that is supported by earlier versions of SQL Server. Please review Non-XML Format Files (SQL Server) for detailed information. The following command will use the bcp utility to generate a non-xml format file, myIdentity.fmt, based on the schema of myIdentity. To use a bcp command to create a format file, specify the format argument and use nul instead of a data-file path. The format option also requires the -f option. In addition, for this example, the qualifier c is used to specify character data, t, is used to specify a comma as a field terminator, and T is used to specify a trusted connection using integrated security. At a command prompt, enter the following command:

bcp TestDatabase.dbo.myIdentity format nul -c -f D:\BCP\myIdentity.fmt -t, -T

REM Review file
Notepad D:\BCP\myIdentity.fmt

Important

Ensure your non-XML format file ends with a carriage return\line feed. Otherwise you will likely receive the following error message:

SQLState = S1000, NativeError = 0
Error = [Microsoft][ODBC Driver 13 for SQL Server]I/O error while reading BCP format file

Examples

The examples below use the database, datafile, and format files created above.

Using bcp and Keeping Identity Values without a Format File

-E switch. At a command prompt, enter the following command:

REM Truncate table (for testing)
SQLCMD -Q "TRUNCATE TABLE TestDatabase.dbo.myIdentity;"

REM Import data
bcp TestDatabase.dbo.myIdentity IN D:\BCP\myIdentity.bcp -T -c -t, -E

REM Review results
SQLCMD -Q "SELECT * FROM TestDatabase.dbo.myIdentity;"

Using bcp and Keeping Identity Values with a Non-XML Format File

-E and -f switches. At a command prompt, enter the following command:

REM Truncate table (for testing)
SQLCMD -Q "TRUNCATE TABLE TestDatabase.dbo.myIdentity;"

REM Import data
bcp TestDatabase.dbo.myIdentity IN D:\BCP\myIdentity.bcp -f D:\BCP\myIdentity.fmt -T -E

REM Review results
SQLCMD -Q "SELECT * FROM TestDatabase.dbo.myIdentity;"

Using bcp and Generated Identity Values without a Format File

Using defaults. At a command prompt, enter the following command:

REM Truncate table (for testing)
SQLCMD -Q "TRUNCATE TABLE TestDatabase.dbo.myIdentity;"

REM Import data
bcp TestDatabase.dbo.myIdentity IN D:\BCP\myIdentity.bcp -T -c -t,

REM Review results
SQLCMD -Q "SELECT * FROM TestDatabase.dbo.myIdentity;"

Using bcp and Generated Identity Values with a Non-XML Format File

Using defaults and -f switch. At a command prompt, enter the following command:

REM Truncate table (for testing)
SQLCMD -Q "TRUNCATE TABLE TestDatabase.dbo.myIdentity;"

REM Import data
bcp TestDatabase.dbo.myIdentity IN D:\BCP\myIdentity.bcp -f D:\BCP\myIdentity.fmt -T

REM Review results
SQLCMD -Q "SELECT * FROM TestDatabase.dbo.myIdentity;"

Using BULK INSERT and Keeping Identity Values without a Format File

KEEPIDENTITY argument. Execute the following Transact-SQL in Microsoft SQL Server Management Studio (SSMS):

USE TestDatabase;
GO

TRUNCATE TABLE dbo.myIdentity; -- for testing
BULK INSERT dbo.myIdentity
	FROM 'D:\BCP\myIdentity.bcp'
	WITH (
		DATAFILETYPE = 'char',  
		FIELDTERMINATOR = ',',  
		KEEPIDENTITY
		);

-- review results
SELECT * FROM TestDatabase.dbo.myIdentity;

Using BULK INSERT and Keeping Identity Values with a Non-XML Format File

KEEPIDENTITY and the FORMATFILE argument. Execute the following Transact-SQL in Microsoft SQL Server Management Studio (SSMS):

USE TestDatabase;
GO

TRUNCATE TABLE dbo.myIdentity; -- for testing
BULK INSERT dbo.myIdentity
   FROM 'D:\BCP\myIdentity.bcp'
   WITH (
		FORMATFILE = 'D:\BCP\myIdentity.fmt',
		KEEPIDENTITY
		);

-- review results
SELECT * FROM TestDatabase.dbo.myIdentity;

Using BULK INSERT and Generated Identity Values without a Format File

Using defaults. Execute the following Transact-SQL in Microsoft SQL Server Management Studio (SSMS):

USE TestDatabase;
GO

TRUNCATE TABLE dbo.myIdentity;  -- for testing
BULK INSERT dbo.myIdentity
   FROM 'D:\BCP\myIdentity.bcp'
   WITH (
      DATAFILETYPE = 'char',  
      FIELDTERMINATOR = ','
	  );

-- review results
SELECT * FROM TestDatabase.dbo.myIdentity;

Using BULK INSERT and Generated Identity Values with a Non-XML Format File

Using defaults and FORMATFILE argument. Execute the following Transact-SQL in Microsoft SQL Server Management Studio (SSMS):

USE TestDatabase;
GO

TRUNCATE TABLE dbo.myIdentity;  -- for testing
BULK INSERT dbo.myIdentity
   FROM 'D:\BCP\myIdentity.bcp'
   WITH (
		FORMATFILE = 'D:\BCP\myIdentity.fmt'
		);

-- review results
SELECT * FROM TestDatabase.dbo.myIdentity;

Using OPENROWSET(BULK...) and Keeping Identity Values with a Non-XML Format File

KEEPIDENTITY table hint and FORMATFILE argument. Execute the following Transact-SQL in Microsoft SQL Server Management Studio (SSMS):

USE TestDatabase;
GO

TRUNCATE TABLE dbo.myIdentity;  -- for testing
INSERT INTO dbo.myIdentity
WITH (KEEPIDENTITY) 
(PersonID, FirstName, LastName, BirthDate)
	SELECT *
	FROM OPENROWSET (
		BULK 'D:\BCP\myIdentity.bcp', 
		FORMATFILE = 'D:\BCP\myIdentity.fmt'  
		) AS t1;

-- review results
SELECT * FROM TestDatabase.dbo.myIdentity;

Using OPENROWSET(BULK...) and Generated Identity Values with a Non-XML Format File