SubscriptionConditionEventRule.SqlExpression Property

Articolo
12/15/2008

Gets or sets the Transact-SQL query used to generate notifications from the input and subscription data.

Spazio dei nomi: Microsoft.SqlServer.Management.Nmo
Assembly : Microsoft.SqlServer.Smo (in microsoft.sqlserver.smo.dll)

Sintassi

'Dichiarazione
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)

Valore proprietà

A String, between 1 and 100000 characters in length, that specifies the Transact-SQL query to run each time the rule is fired.

Osservazioni

The SqlExpression property 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 Definizione di azioni condizionali.

Esempio

The following example shows how to define a condition-based, event-driven subscription rule and add it to a subscription class:

// Add a rule to generate condition-based, event notifications
SubscriptionConditionEventRule flightConditionEventRule = 
    new SubscriptionConditionEventRule(
    flightSubscriptions, "FlightConditionEventRule");
flightConditionEventRule.EventClassName = "FlightEvents";
flightConditionEventRule.ActionTimeout = new TimeSpan(0, 2, 0);
flightConditionEventRule.SqlLoginName = "MyLowPrivLogin";
flightConditionEventRule.SqlUserName = "MyLowPrivUser";
flightConditionEventRule.InputTypeName = "FlightEvents";
flightConditionEventRule.InputTypeSchema = "MyAppSchema";
flightConditionEventRule.SqlExpression =
    "INSERT INTO MyAppSchema.FlightNotifications (SubscriberId, " +
    "DeviceName, SubscriberLocale, LeavingFrom, GoingTo, Price) " +
    "SELECT [Subscription.SubscriberId], [Subscription.DeviceName], " +
    "[Subscription.SubscriberLocale], " +
    "[Input.LeavingFrom], [Input.GoingTo], [Input.Price] " +
    "FROM MyAppSchema.FlightConditionEventRule;";
flightSubscriptions.SubscriptionConditionEventRules.Add(
    flightConditionEventRule);

' Add a rule to generate condition-based, event notifications
Dim flightConditionEventRule As _
    SubscriptionConditionEventRule = _
    New SubscriptionConditionEventRule( _
    flightSubscriptions, "FlightConditionEventRule")
flightConditionEventRule.EventClassName = "FlightEvents"
flightConditionEventRule.ActionTimeout = New TimeSpan(0, 2, 0)
flightConditionEventRule.SqlLoginName = "MyLowPrivLogin"
flightConditionEventRule.SqlUserName = "MyLowPrivUser"
flightConditionEventRule.InputTypeName = "FlightEvents"
flightConditionEventRule.InputTypeSchema = "MyAppSchema"
flightConditionEventRule.SqlExpression = _
 "INSERT INTO MyAppSchema.FlightNotifications " + _
 "(SubscriberId, DeviceName, SubscriberLocale, LeavingFrom, " + _
 "GoingTo, Price) SELECT [Subscription.SubscriberId], " + _
 "[Subscription.DeviceName], [Subscription.SubscriberLocale], " + _
 "[Input.LeavingFrom], [Input.GoingTo], [Input.Price] " + _
 "FROM MyAppSchema.FlightConditionEventRule;"
flightSubscriptions.SubscriptionConditionEventRules.Add( _
    flightConditionEventRule)

Thread Safety

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.