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# Transact-SQL Syntax Conventions (Transact-SQL)
[!INCLUDE[tsql-appliesto-ss2008-all_md](../../includes/tsql-appliesto-ss2008-all-md.md)]

  The following table lists and describes conventions that are used in the syntax diagrams in the [!INCLUDE[tsql](../../includes/tsql-md.md)] Reference.  
  
|Convention|Used for|  
|----------------|--------------|  
|UPPERCASE|[!INCLUDE[tsql](../../includes/tsql-md.md)] keywords.|  
|*italic*|User-supplied parameters of [!INCLUDE[tsql](../../includes/tsql-md.md)] syntax.|  
|**bold**|Database names, table names, column names, index names, stored procedures, utilities, data type names, and text that must be typed exactly as shown.|  
|**underline**|Indicates the default value applied when the clause that contains the underlined value is omitted from the statement.|  
|| (vertical bar)|Separates syntax items enclosed in brackets or braces. You can use only one of the items.|  
|`[ ]` (brackets)|Optional syntax items. Do not type the brackets.|  
|{ } (braces)|Required syntax items. Do not type the braces.|  
|[**,**...*n*]|Indicates the preceding item can be repeated *n* number of times. The occurrences are separated by commas.|  
|[...*n*]|Indicates the preceding item can be repeated *n* number of times. The occurrences are separated by blanks.|  
|;|[!INCLUDE[tsql](../../includes/tsql-md.md)] statement terminator.Although the semicolon is not required for most statements in this version of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)], it will be required in a future version.|  
|\<label> ::=|The name for a block of syntax. This convention is used to group and label sections of lengthy syntax or a unit of syntax that can be used in more than one location within a statement. Each location in which the block of syntax can be used is indicated with the label enclosed in chevrons: \<label>.<br /><br /> A set is a collection of expressions, for example \<grouping set>; and a list is a collection of sets, for example \<composite element list>.|  
  
## Multipart Names  
 Unless specified otherwise, all [!INCLUDE[tsql](../../includes/tsql-md.md)] references to the name of a database object can be a four-part name in the following form:  
  
*server_name* **.**[*database_name*]**.**[*schema_name*]**.***object_name*  
  
 | *database_name***.**[*schema_name*]**.***object_name*  
  
 | *schema_name***.***object_name*  
  
 | *object_name*  
  
*server_name*  
Specifies a linked server name or remote server name.  
  
*database_name*  
Specifies the name of a [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] database when the object resides in a local instance of [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)]. When the object is in a linked server, *database_name* specifies an OLE DB catalog.  
  
*schema_name*  
Specifies the name of the schema that contains the object if the object is in a [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] database. When the object is in a linked server, *schema_name* specifies an OLE DB schema name.  
  
*object_name*  
Refers to the name of the object.  
  
When referencing a specific object, you do not always have to specify the server, database, and schema for the [!INCLUDE[ssDEnoversion](../../includes/ssdenoversion-md.md)] to identify the object. However, if the object cannot be found, an error is returned.  
  
> [!NOTE]  
> To avoid name resolution errors, we recommend specifying the schema name whenever you specify a schema-scoped object.  
  
To omit intermediate nodes, use periods to indicate these positions. The following table shows the valid formats of object names.  
  
|Object reference format|Description|  
|-----------------------------|-----------------|  
|*server* **.** *database* **.** *schema* **.** *object*|Four-part name.|  
|*server* **.** *database* **..** *object*|Schema name is omitted.|  
|*server* **..** *schema* **.** *object*|Database name is omitted.|  
|*server* **...** *object*|Database and schema name are omitted.|  
|*database* **.** *schema* **.** *object*|Server name is omitted.|  
|*database* **..** *object*|Server and schema name are omitted.|  
|*schema* **.** *object*|Server and database name are omitted.|  
|*object*|Server, database, and schema name are omitted.|  
  
## Code Example Conventions  
Unless stated otherwise, the examples provided in the [!INCLUDE[tsql](../../includes/tsql-md.md)] Reference were tested by using [!INCLUDE[ssManStudioFull](../../includes/ssmanstudiofull-md.md)] and its default settings for the following options:  
  
-   ANSI_NULLS  
-   ANSI_NULL_DFLT_ON  
-   ANSI_PADDING  
-   ANSI_WARNINGS  
-   CONCAT_NULL_YIELDS_NULL  
-   QUOTED_IDENTIFIER  
  
Most code examples in the [!INCLUDE[tsql](../../includes/tsql-md.md)] Reference have been tested on servers that are running a case-sensitive sort order. The test servers were typically running the ANSI/ISO 1252 code page.  
  
Many code examples prefix Unicode character string constants with the letter **N**. Without the **N** prefix, the string is converted to the default code page of the database. This default code page may not recognize certain characters.  
  
## "Applies to" References  
The [!INCLUDE[tsql](../../includes/tsql-md.md)] reference includes articles related to [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] ([!INCLUDE[ssKatmai](../../includes/sskatmai-md.md)] through [!INCLUDE[ssCurrent](../../includes/sscurrent-md.md)]), [!INCLUDE[ssSDSfull](../../includes/sssdsfull-md.md)], and [!INCLUDE[ssSDWfull](../../includes/sssdwfull-md.md)].   

Near the top of each article is a section indicating which products support the subject of the article. If a product is omitted, then the feature described by the article is not available in that product. For example, availability groups were introduced in [!INCLUDE[ssSQL11](../../includes/sssql11-md.md)]. The **CREATE AVAILABILITY GROUP** article indicates it applies to [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] ([!INCLUDE[ssSQL11](../../includes/sssql11-md.md)] through [!INCLUDE[ssCurrent](../../includes/sscurrent-md.md)]) because it does not apply to [!INCLUDE[ssKatmai](../../includes/sskatmai-md.md)], [!INCLUDE[ssKilimanjaro](../../includes/sskilimanjaro-md.md)], or [!INCLUDE[ssSDSfull](../../includes/sssdsfull-md.md)].  
  
In some cases, the general subject of the article can be used in a product, but all of the arguments are not supported. For example, contained database users were introduced in [!INCLUDE[ssSQL11](../../includes/sssql11-md.md)]. The **CREATE USER** statement can be used in any [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] product, however the **WITH PASSWORD** syntax cannot be used with older versions. In this case, additional **Applies to** sections are inserted into the appropriate argument descriptions in the body of the article.  
  
## See Also  
[Transact-SQL Reference &#40;Database Engine&#41;](../../t-sql/transact-sql-reference-database-engine.md)    
[Reserved Keywords &#40;Transact SQL&#41;](../../t-sql/language-elements/reserved-keywords-transact-sql.md)      
[Transact-SQL Design Issues](http://msdn.microsoft.com/library/dd193411.aspx)    
[Transact-SQL Naming Issues](http://msdn.microsoft.com/library/dd193246.aspx)        
[Transact-SQL Performance Issues](http://msdn.microsoft.com/library/dd172117.aspx)