C# – Bulk insert with destination table identity column

cc#-3.0c#-4.0sql server

I'm trying to do a bulk insert from a DataTable into a table in SQL Server, but in my datatable I don't have an id column. When I call the WriteToServer method, it throws an exception with the message

cannot insert null in column id

Code:

CREATE TABLE [dbo].[TBL_HISTORY]
(
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [VAR1] [int] NOT NULL,
    [VAR2] [datetime] NOT NULL,
    [VAR3] [smallint] NOT NULL
)

AND my dataTable has the following data

[VAR1], [VAR2], [VAR3]

C# code:

using(SqlBulkCopy bulk = new SqlBulkCopy(this.mConnection,SqlBulkCopyOptions.UseInternalTransaction | SqlBulkCopyOptions.KeepIdentity, null))
{
    bulk.DestinationTableName = ToTable;

    bulk.WriteToServer(dt);    // here exception is thrown
}

Best Answer

You need to remove the SqlBulkCopyOptions.KeepIdentity option. You are telling it to use the identity that you provide and there is none, aka null.

https://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlbulkcopyoptions%28v=vs.110%29.aspx

KeepIdentity

Preserve source identity values. When not specified, identity values are assigned by the destination.

Syntax:

ALTER TABLE {TABLENAME} 
ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL} 
CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE}
WITH VALUES

Example:

ALTER TABLE SomeTable
        ADD SomeCol Bit NULL --Or NOT NULL.
 CONSTRAINT D_SomeTable_SomeCol --When Omitted a Default-Constraint Name is autogenerated.
    DEFAULT (0)--Optional Default-Constraint.
WITH VALUES --Add if Column is Nullable and you want the Default Value for Existing Records.

Notes:

Optional Constraint Name:
If you leave out CONSTRAINT D_SomeTable_SomeCol then SQL Server will autogenerate
a Default-Contraint with a funny Name like: DF__SomeTa__SomeC__4FB7FEF6

Optional With-Values Statement:
The WITH VALUES is only needed when your Column is Nullable
and you want the Default Value used for Existing Records.
If your Column is NOT NULL, then it will automatically use the Default Value
for all Existing Records, whether you specify WITH VALUES or not.

How Inserts work with a Default-Constraint:
If you insert a Record into SomeTable and do not Specify SomeCol's value, then it will Default to 0.
If you insert a Record and Specify SomeCol's value as NULL (and your column allows nulls),
then the Default-Constraint will not be used and NULL will be inserted as the Value.

Notes were based on everyone's great feedback below.
Special Thanks to:
@Yatrix, @WalterStabosz, @YahooSerious, and @StackMan for their Comments.

Sql-server – How to check if a column exists in a SQL Server table

SQL Server 2005 onwards:

IF EXISTS(SELECT 1 FROM sys.columns 
          WHERE Name = N'columnName'
          AND Object_ID = Object_ID(N'schemaName.tableName'))
BEGIN
    -- Column Exists
END

Martin Smith's version is shorter:

IF COL_LENGTH('schemaName.tableName', 'columnName') IS NOT NULL
BEGIN
    -- Column Exists
END

Best Answer

Related Solutions

Sql – Add a column with a default value to an existing table in SQL Server

Syntax:

Example:

Notes:

Sql-server – How to check if a column exists in a SQL Server table

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