SqlExpression Element for Protocol/Fields/Field (ADF)

Specifies a valid Transact-SQL expression that provides the protocol field value.

语法

<NotificationClasses>
    <NotificationClass>
        ...
        <Protocols>
            <Protocol>
                ...
                <Fields>
                    <Field>
                        ...
                        <SqlExpression>

Element Characteristics

Characteristic	Description
Data type	string, between 0 and 4,000 characters in length.
Default value	None.
Occurrence	Optional once per Field element.
Updates	Can be modified, but not added or deleted, when updating the application.

Element Relationships

Relationship	Elements
Parent element	Field Element for Protocol/Fields (ADF)
Child elements	None.

备注

A Transact-SQL expression is a combination of identifiers, values, and operators that the database engine 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）.

Enclose string constants in single quotation marks.

If a Field element does not include a SqlExpression element, it must include a FieldReference element.

示例

The following example shows a how to define a Transact-SQL expression that concatenates a string with a notification field. This could be used as a subject line for an e-mail message.

<SqlExpression>
    'Stock Price Update for ' + StockSymbol
</SqlExpression>

请参阅

参考

Application Definition File Reference

其他资源

指定传递协议名称和字段
表达式（数据库引擎）
更新实例和应用程序

帮助和信息

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