---
title: "sys.sp_cdc_generate_wrapper_function (Transact-SQL)"
description: "Generates scripts to create wrapper functions for the change data capture query functions that are available in SQL Server."
author: markingmyname
ms.author: maghan
ms.reviewer: wiassaf, randolphwest
ms.date: 08/21/2024
ms.service: sql
ms.subservice: system-objects
ms.topic: "reference"
f1_keywords:
  - "sp_cdc_generate_wrapper_function_TSQL"
  - "sp_cdc_generate_wrapper_function"
  - "sys.sp_cdc_generate_wrapper_function_TSQL"
  - "sys.sp_cdc_generate_wrapper_function"
helpviewer_keywords:
  - "sys.sp_cdc_generate_wrapper_function"
  - "sp_cdc_generate_wrapper_function"
dev_langs:
  - "TSQL"
---
# sys.sp_cdc_generate_wrapper_function (Transact-SQL)

[!INCLUDE [SQL Server](../../includes/applies-to-version/sqlserver.md)]

Generates scripts to create wrapper functions for the change data capture query functions that are available in [!INCLUDE [ssNoVersion](../../includes/ssnoversion-md.md)]. The API supported in the generated wrappers enables specifying the query interval as a datetime interval. This specification makes the function good for use in many warehousing applications, including those applications developed by [!INCLUDE [ssISnoversion](../../includes/ssisnoversion-md.md)] package designers who are using change data capture technology to determine incremental load.

For more information on the functions generated by `sys.sp_cdc_generate_wrapper_function`, see [sys.fn_all_changes_<capture_instance>](../system-functions/sys-fn-all-changes-capture-instance-transact-sql.md) and [sys.fn_net_changes_<capture_instance>](../system-functions/sys-fn-net-changes-capture-instance-transact-sql.md).

:::image type="icon" source="../../includes/media/topic-link-icon.svg" border="false"::: [Transact-SQL syntax conventions](../../t-sql/language-elements/transact-sql-syntax-conventions-transact-sql.md)

## Syntax

```syntaxsql
sys.sp_cdc_generate_wrapper_function
    [ [ @capture_instance sysname = ] 'capture_instance' ]
    [ , [ @closed_high_end_point = ] closed_high_end_pt ]
    [ , [ @column_list = ] N'column_list' ]
    [ , [ @update_flag_list = ] N'update_flag_list' ]
[ ; ]
```

## Arguments

#### [ @capture_instance = ] '*capture_instance*'

The capture instance that scripts are generated for *@capture_instance* is **sysname** and has a default value of `NULL`. If a value is omitted or explicitly set to `NULL`, wrapper scripts are generated for all capture instances.

#### [ @closed_high_end_point = ] *high_end_pt_flag*

The flag bit that indicates whether changes that have a commit time equal to the high endpoint are included within the extraction interval by the generated procedure. *@closed_high_end_point* is **bit** and has a default value of `1`, which indicates that the endpoint should be included. A value of `0` indicates that all commit times are strictly less than the high endpoint.

#### [ @column_list = ] N'*column_list*'

A list of captured columns included in the result set that is returned by the wrapper function. *@column_list* is **nvarchar(max)** and has a default value of `NULL`. When `NULL` is specified, all captured columns are included.

#### [ @update_flag_list = ] N'*update_flag_list*'

A list of included columns for which an update flag is included in the result set returned by the wrapper function. *@update_flag_list* is **nvarchar(max)** and has a default value of `NULL`. When `NULL` is specified, no update flags are included.

## Return code values

`0` (success) or `1` (failure).

## Result set

| Column name | Column type | Description |
| --- | --- | --- |
| `function_name` | **nvarchar(145)** | Name of the generated function. |
| `create_script` | **nvarchar(max)** | The script that creates the capture-instance wrapper function. |

## Remarks

The script that creates the function to wrap the all-changes query for a capture instance is always generated. If the capture instance supports net-changes queries, the script to generate a wrapper for this query is also generated.

## Examples

The following example show how you can use `sys.sp_cdc_generate_wrapper_function` to create wrappers for all the change data capture functions.

```sql
DECLARE @wrapper_functions TABLE (
    function_name SYSNAME,
    create_script NVARCHAR(MAX)
);

INSERT INTO @wrapper_functions
EXEC sys.sp_cdc_generate_wrapper_function;

DECLARE @create_script NVARCHAR(MAX);

DECLARE #hfunctions CURSOR LOCAL FAST_FORWARD
FOR
SELECT create_script
FROM @wrapper_functions;

OPEN #hfunctions;

FETCH #hfunctions
INTO @create_script;

WHILE (@@fetch_status <> -1)
BEGIN
    EXEC sp_executesql @create_script

    FETCH #hfunctions
    INTO @create_script
END;

CLOSE #hfunctions;

DEALLOCATE #hfunctions;
```

## Related content

- [Change Data Capture stored procedures (Transact-SQL)](change-data-capture-stored-procedures-transact-sql.md)
- [Change Data Capture (SSIS)](../../integration-services/change-data-capture/change-data-capture-ssis.md)