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SqlFunctionAttribute Class

Used to mark a method definition of a user-defined aggregate as a function in SQL Server. The properties on the attribute reflect the physical characteristics used when the type is registered with SQL Server.


Namespace:  Microsoft.SqlServer.Server
Assembly:  System.Data (in System.Data.dll)

[AttributeUsageAttribute(AttributeTargets.Method, AllowMultiple = false, Inherited = false)]
public class SqlFunctionAttribute : Attribute

The SqlFunctionAttribute type exposes the following members.

Public methodSqlFunctionAttributeAn optional attribute on a user-defined aggregate, used to indicate that the method should be registered in SQL Server as a function. Also used to set the DataAccess, FillRowMethodName, IsDeterministic, IsPrecise, Name, SystemDataAccess, and TableDefinition properties of the function attribute.

Public propertyDataAccessIndicates whether the function involves access to user data stored in the local instance of SQL Server.
Public propertyFillRowMethodNameThe name of a method in the same class as the table-valued function (TVF) that is used by the TVF contract.
Public propertyIsDeterministicIndicates whether the user-defined function is deterministic.
Public propertyIsPreciseIndicates whether the function involves imprecise computations, such as floating point operations.
Public propertyNameThe name under which the function should be registered in SQL Server.
Public propertySystemDataAccessIndicates whether the function requires access to data stored in the system catalogs or virtual system tables of SQL Server.
Public propertyTableDefinitionA string that represents the table definition of the results, if the method is used as a table-valued function (TVF).
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)

Public methodEqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public methodMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

Explicit interface implemetationPrivate method_Attribute.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)

The following example shows an aggregate function that returns a list of files in the specified directory path.

[SqlFunctionAttribute(FillRowMethodName = "FillFileRow")]
public static IEnumerable GetFileDetails(string directoryPath)
      DirectoryInfo di = new DirectoryInfo(directoryPath);
      return di.GetFiles();
   catch (DirectoryNotFoundException dnf)
      return new string[1] { dnf.ToString() };

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.