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ColumnAttribute.Expression Property

Gets or sets whether a column is a computed column in a database.

Namespace:  System.Data.Linq.Mapping
Assembly:  System.Data.Linq (in System.Data.Linq.dll)

public string Expression { get; set; }

Property Value

Type: System.String
Default = empty.

Use this property when you use CreateDatabase to define a column as containing computed values.

For example, if you want to create a column defined in SQL as InventoryVal AS UnitPrice * UnitsInStock, use the following expression string: "UnitPrice * UnitsInStock".

NoteNote

LINQ to SQL does not support computed columns as primary keys.

	[Column(Storage="_UnitPrice", DbType="Money",Expression="UnitPrice + 1.00")]
	public System.Nullable<decimal> UnitPrice
	{
		get
		{
			return this._UnitPrice;
		}
		set
		{
			if ((this._UnitPrice != value))
			{
				this.OnUnitPriceChanging(value);
				this.SendPropertyChanging();
				this._UnitPrice = value;
				this.SendPropertyChanged("UnitPrice");
				this.OnUnitPriceChanged();
			}
		}
	}

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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