SqlExpression Element for ConditionAction (ADF)
Specifies the Transact-SQL query used to generate notifications from the input and subscription data.
语法
<ConditionAction>
...
<SqlExpression>
Element Characteristics
| Characteristic | Description |
|---|---|
Data type |
string between 1 and 100000 characters. |
Default value |
None. |
Occurrence |
Required once per ConditionAction element. |
Updates |
You can modify this element, but cannot add or delete it when updating the application. You can add and delete the parent ConditionAction element. |
Element Relationships
| Relationship | Elements |
|---|---|
Parent element |
|
Child elements |
None. |
备注
The SqlExpression element contains the core query for generating notifications, which selects subscription and input fields and adds them to the notification table.
The query must select subscription and input fields from a view that joins subscription and input data. Subscription fields in the view have names in the form [Subscription.SubscriptionFieldName]. Input (event) fields have names in the form [Input.EventFieldName].
Subscribers create the equivalent of the WHERE clause for the query in their subscriptions through a subscription management interface. Notification Services evaluates the condition actions for all relevant subscriptions and then generates notifications.
For more information about condition actions, and a template for the Transact-SQL expression, see 定义条件操作.
示例
The following example shows how to define a condition action. The query in the Transact-SQL expression selects data from the MyAppSchema.WeatherEventRule view, which contains data from the subscription class and from the MyAppSchema.WeatherEvents event view.
<ConditionAction>
<SqlLogin>[MyLowPrivLogin]</SqlLogin>
<SqlUser>[MyLowPrivUser]</SqlUser>
<InputName>WeatherEvents</InputName>
<InputSchema>MyAppSchema</InputSchema>
<SqlExpression>
INSERT INTO MyAppSchema.WeatherNotifications(SubscriberId,
DeviceName, SubscriberLocale, City, Forecast)
SELECT [Subscription.SubscriberId], [Subscription.DeviceName],
[Subscription.SubscriberLocale], [Input.City],
[Input.Forecast])
FROM MyAppSchema.WeatherEventRule;
</SqlExpression>
</ConditionAction>
请参阅
参考
Application Definition File Reference
概念
Instance Configuration File Reference
其他资源
INSERT (Transact-SQL)
SELECT (Transact-SQL)
定义条件操作
定义订阅规则