Chronicles Element for EventClass (ADF)
Provides a location for defining one or more Transact-SQL statements that determine the table structure for the chronicle tables used by the event class.
语法
<EventClasses>
<EventClass>
...
<Chronicles>
Element Characteristics
Characteristic | Description |
---|---|
Data type |
None. |
Default value |
None. |
Occurrence |
Optional once per EventClass element. |
Updates |
Can be added and deleted when updating the application. |
Element Relationships
Relationship | Elements |
---|---|
Parent element |
|
Child elements |
备注
Event chronicles are optional; use the Chronicles element and its child elements only if you need to maintain event information outside of the event tables used by event classes. For more information, see 为事件类定义历史记录.
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If you add or delete the Chronicles 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 in the existing event tables is permanently deleted. |
示例
The following example shows a Chronicles element (and its child elements) that deletes any existing table named StockEventChron and then creates the StockEventChron event chronicle table. This table consists of the StockSymbol and StockPrice fields.
<Chronicles>
<Chronicle>
<ChronicleName>StockEventChron</ChronicleName>
<SqlSchema>
<SqlStatement>
-- Delete any existing table named StockEventChron
IF EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME = 'StockEventChron')
DROP TABLE StockEventChron
</SqlStatement>
<SqlStatement>
-- Create the chronicle table
CREATE TABLE StockEventChron
(
StockSymbol char(10),
StockHighPrice money
PRIMARY KEY (StockSymbol)
)
</SqlStatement>
</SqlSchema>
</Chronicle>
</Chronicles>
请参阅
参考
Application Definition File Reference