---
title: "Modules and Prologs (XQuery) | Microsoft Docs"
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ms.date: "03/06/2017"
ms.prod: sql
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ms.technology: xml
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helpviewer_keywords: 
  - "XQuery, prolog"
  - "prolog"
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---
# Modules and Prologs (XQuery)
[!INCLUDE[tsql-appliesto-ss2012-xxxx-xxxx-xxx-md](../includes/tsql-appliesto-ss2012-xxxx-xxxx-xxx-md.md)]

  [XQuery Prolog](../xquery/modules-and-prologs-xquery-prolog.md) is a series of namespace declarations. In using the declare namespace in prolog, you can specify prefix to namespace binding and use the prefix in the query body.  
  
## Implementation Limitations  
 The following XQuery specifications are not supported in this implementation:  
  
-   Module declaration (`version`)  
  
-   Module declaration (`module namespace`)  
  
-   Xmpspacedeclaration (`xmlspace`)  
  
-   Default collation declaration (`declare default collation`)  
  
-   Base URI declaration (`declare base-uri`)  
  
-   Construction declaration (`declare construction`)  
  
-   Default ordering declaration (`declare ordering`)  
  
-   Schema import (`import schema namespace`)  
  
-   Module import (`import module`)  
  
-   Variable declaration in the prolog (`declare variable`)  
  
-   Function declaration (`declare function`)  
  
## In This Section  
 [XQuery Prolog](../xquery/modules-and-prologs-xquery-prolog.md)  
 Describes the XQuery prolog.  
  
## See Also  
 [XQuery Language Reference (SQL Server)](../xquery/xquery-language-reference-sql-server.md)