FieldTypeMods Element for EventClass/Schema/Field (ADF)

Specifies optional Microsoft SQL Server field attributes for an event field, such as null and default values.

语法

<EventClasses>
    <EventClass>
        ...
        <Schema>
            <Field>
                ...
                <FieldTypeMods>

Element Characteristics

Characteristic	Description
Data type	string, between 1 and 255 characters in length.
Default value	None.
Occurrence	Optional once per Field element.
Updates	Can be added, deleted, and modified when updating the application.

Element Relationships

Relationship	Elements
Parent element	Field Element for EventClass/Schema (ADF)
Child elements	None.

备注

The possible values for FieldTypeMods come from the table column modifiers, such as NOT NULL or DEFAULTconstant_expression. The value must conform to the Transact-SQL syntax conventions.

注意：
You cannot specify an event data field as an Identity column in SQL Server. Notification Services already uses the Identity property to specify a system-generated EventId field.

For more information about possible values, see CREATE TABLE (Transact-SQL).

重要提示：
If you update a FieldTypeMods element, updating the application deletes and re-creates the event class to which it corresponds. This includes dropping and re-creating the SQL Server tables and indexes used by this event class. Any data existing in the original event class tables is permanently deleted.

示例

The following example shows how to specify that the event class field does not accept a null value.

<FieldTypeMods>NOT NULL</FieldTypeMods>

请参阅

参考

Application Definition File Reference

其他资源

定义核心事件类属性
更新实例和应用程序

帮助和信息

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