---
title: "How Extended Stored Procedures Work | Microsoft Docs"
ms.custom: ""
ms.date: "03/15/2017"
ms.prod: sql
ms.prod_service: "database-engine"
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ms.topic: "reference"
helpviewer_keywords: 
  - "extended stored procedures [SQL Server], about extended stored procedures"
ms.assetid: 6e946d8c-3268-4b59-8a1c-1637909cd701
author: "rothja"
ms.author: "jroth"
---
# How Extended Stored Procedures Work

[!INCLUDE[appliesto-ss-xxxx-xxxx-xxx-md](../../includes/appliesto-ss-xxxx-xxxx-xxx-md.md)]
    
> [!IMPORTANT]  
>  [!INCLUDE[ssNoteDepFutureDontUse](../../includes/ssnotedepfuturedontuse-md.md)] Use CLR Integration instead.  
  
 The process by which an extended stored procedure works is:  
  
1.  When a client executes an extended stored procedure, the request is transmitted in tabular data stream (TDS) or Simple Object Access Protocol (SOAP) format from the client application to [!INCLUDE[msCoName](../../includes/msconame-md.md)] [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)].  
  
2.  [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] searches for the DLL associated with the extended stored procedure, and loads the DLL if it is not already loaded.  
  
3.  [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] calls the requested extended stored procedure (implemented as a function inside the DLL).  
  
4.  The extended stored procedure passes result sets and return parameters back to the server by through the Extended Stored Procedure API.