SQL Server auto audit updated column

Question

I need to create a trigger on SQL Server to write only updated column into an audit table with table name, column name, previous/new value, date, time and user for specific

Answer 1

We’re using third party tool ApexSQL Audit to generate audit triggers since we have a lot of tables that require auditing.

If you don’t need a third party tool you can use this in trial mode and see how they are implementing triggers and storage tables.

Below is a sample trigger and storage tables I picked up quickly from my database.

Data storage table:

Table that stores details about transactions:

Here is a sample of delete trigger. Note the comment inline

CREATE TRIGGER [dbo].[tr_d_AUDIT_Table_Name]
ON [dbo].[Table_Name]
FOR DELETE
NOT FOR REPLICATION
AS

BEGIN
    DECLARE 
        @IDENTITY_SAVE              varchar(50),
        @AUDIT_LOG_TRANSACTION_ID       Int,
        @PRIM_KEY               nvarchar(4000),
        @ROWS_COUNT             int

    SET NOCOUNT ON


    Select @ROWS_COUNT=count(*) from deleted
    Set @IDENTITY_SAVE = CAST(IsNull(@@IDENTITY,1) AS varchar(50))

    INSERT
    INTO dbo.AUDIT_LOG_TRANSACTIONS
    (
        TABLE_NAME,
        TABLE_SCHEMA,
        AUDIT_ACTION_ID,
        HOST_NAME,
        APP_NAME,
        MODIFIED_BY,
        MODIFIED_DATE,
        AFFECTED_ROWS,
        [DATABASE]
    )
    values(
        'Table_Name',
        'dbo',
        3,  
        CASE 
          WHEN LEN(HOST_NAME()) < 1 THEN ' '
          ELSE HOST_NAME()
        END,
        CASE 
          WHEN LEN(APP_NAME()) < 1 THEN ' '
          ELSE APP_NAME()
        END,
        SUSER_SNAME(),
        GETDATE(),
        @ROWS_COUNT,
        'database_name'
    )

    Set @AUDIT_LOG_TRANSACTION_ID = SCOPE_IDENTITY()

    INSERT
    INTO dbo.AUDIT_LOG_DATA
    (
        AUDIT_LOG_TRANSACTION_ID,
        PRIMARY_KEY_DATA,
        COL_NAME,
        OLD_VALUE_LONG,
        DATA_TYPE
        , KEY1
    )
    SELECT
        @AUDIT_LOG_TRANSACTION_ID,
        convert(nvarchar(1500), IsNull('[Order_ID]='+CONVERT(nvarchar(4000), OLD.[Order_ID], 0), '[Order_ID] Is Null')),
        'Order_ID',
        CONVERT(nvarchar(4000), OLD.[Order_ID], 0),
        'A'
        ,  CONVERT(nvarchar(500), CONVERT(nvarchar(4000), OLD.[Order_ID], 0))
    FROM deleted OLD
    WHERE
        OLD.[Order_ID] Is Not Null

    /*
       Insert statement above is replicated for each column being audited
     */

END