Maps an inheritance hierarchy in a LINQ to SQL application.
Assembly: System.Data.Linq (in System.Data.Linq.dll)
Thetype exposes the following members.
|Code||Gets or sets the discriminator code value in a mapped inheritance hierarchy.|
|IsDefault||Gets or sets whether an object of this type in instantiated when the discriminator value does not match a specified value.|
|Type||Gets or sets the type of the class in the hierarchy.|
|TypeId||When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)|
|Equals||Infrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)|
|Finalize||Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)|
|GetHashCode||Returns the hash code for this instance. (Inherited from Attribute.)|
|GetType||Gets the Type of the current instance. (Inherited from Object.)|
|IsDefaultAttribute||When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)|
|Match||When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)|
|MemberwiseClone||Creates a shallow copy of the current Object. (Inherited from Object.)|
|ToString||Returns a string that represents the current object. (Inherited from Object.)|
|_Attribute.GetIDsOfNames||Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)|
|_Attribute.GetTypeInfo||Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)|
|_Attribute.GetTypeInfoCount||Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)|
|_Attribute.Invoke||Provides access to properties and methods exposed by an object. (Inherited from Attribute.)|
One is specified per mapped class.
Note the following when you map inheritance hierarchies:
All classes in a hierarchy must be mapped to a single table.
The table for an inheritance hierarchy must be declared on the mapped type that is at the top of the hierarchy. You cannot specify the table or mapping attributes in a class that is derived from the top class.
You can use an interface in a hierarchy, but LINQ does not map it.
You can skip a class in the hierarchy when you map classes, but you can query against mapped classes only.
For correct materialization, discriminator code values must be unique and match the values in the database. A row with a discriminator code value that does not exactly match (even by casing) instantiates the class by using IsDefault set to true.
This example shows inheritance mapping for a hierarchy where the top, mapped class (Shape) is abstract.
The following example shows the inclusion of unmapped classes. You can put unmapped classes anywhere in the hierarchy.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, 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.