通过

NotificationComputedField.SqlExpression Property

  • 项目

Gets or sets the Transact-SQL expression that computes the field value.

命名空间: Microsoft.SqlServer.Management.Nmo
程序集: Microsoft.SqlServer.Smo (in microsoft.sqlserver.smo.dll)

语法

声明
Public Property SqlExpression As String

public string SqlExpression { get; set; }

public:
property String^ SqlExpression {
    String^ get ();
    void set (String^ value);
}

/** @property */
public String get_SqlExpression ()

/** @property */
public void set_SqlExpression (String value)

public function get SqlExpression () : String

public function set SqlExpression (value : String)

属性值

A String, between 0 and 4000 characters in length, that contains the Transact-SQL statement that computes the field value.

备注

The SqlExpression property is required.

A Transact-SQL expression is a combination of identifiers, values, and operators that the 数据库引擎 can evaluate to get a result. You can use any expression that can be part of a SELECT statement. The terms of the expression can be any of the following:

  • Constants.

  • Calls to functions.

  • The notification fields defined in the ADF (but not computed fields).

  • The following built-in notification fields:

    • SubscriberId

    • DeviceName

    • DeviceTypeName

    • DeviceAddress

    • SubscriberLocale

    • DeliveryChannelName

For more information, see 表达式（数据库引擎）.

If you update the SqlExpression property, updating the application deletes and re-creates the notification class to which it corresponds. This includes dropping and re-creating the Microsoft SQL Server tables used by this notification class. Any data existing in the original SQL Server tables is permanently deleted.

示例

The following example shows how to define a computed field for a notification class:

NotificationComputedField computedPrice = 
    new NotificationComputedField(flightNotifications, 
    "FormattedPrice");
computedPrice.SqlExpression = "CONVERT(NVARCHAR(10), Price, 1)";
flightNotifications.NotificationComputedFields.Add(computedPrice);

Dim computedPrice As NotificationComputedField = _
    New NotificationComputedField(flightNotifications, _
    "FormattedPrice")
computedPrice.SqlExpression = "CONVERT(NVARCHAR(10), Price, 1)"
flightNotifications.NotificationComputedFields.Add( _
    computedPrice)

线程安全

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

平台

开发平台

有关支持的平台列表，请参阅安装 SQL Server 2005 的硬件和软件要求。

目标平台

有关支持的平台列表，请参阅安装 SQL Server 2005 的硬件和软件要求。

请参阅

参考

NotificationComputedField Class
NotificationComputedField Members
Microsoft.SqlServer.Management.Nmo Namespace

其他资源

定义通知架构
SqlExpression Element for ComputedField (ADF)