关于INFA的Update Strategy 设置

Specifying an Operation for All Rows

When you configure a session, you can select a single database operation for all rows using the Treat Source Rows As setting.

The following table displays the options for the Treat Source Rows As setting:

Setting

Description

Insert

Treat all rows as inserts. If inserting the row violates a primary or foreign key constraint in the database, the Integration Service rejects the row.

Delete

Treat all rows as deletes. For each row, if the Integration Service finds a corresponding row in the target table (based on the primary key value), the Integration Service deletes it. Note that the primary key constraint must exist in the target definition in the repository.

Update

Treat all rows as updates. For each row, the Integration Service looks for a matching primary key value in the target table. If it exists, the Integration Service updates the row. The primary key constraint must exist in the target definition.

Data Driven

Integration Service follows instructions coded into Update Strategy and Custom transformations within the session mapping to determine how to flag rows for insert, delete, update, or reject.

If the mapping for the session contains an Update Strategy transformation, this field is marked Data Driven by default.

If you do not choose Data Driven when a mapping contains an Update Strategy or Custom transformation, the Workflow Manager displays a warning. When you run the session, the Integration Service does not follow instructions in the Update Strategy or Custom transformation in the mapping to determine how to flag rows.

The following table describes the update strategy for each setting:

Setting

Use To

Insert

Populate the target tables for the first time, or maintain a historical data warehouse. In the latter case, you must set this strategy for the entire data warehouse, not just a select group of target tables.

Delete

Clear target tables.

Update

Update target tables. You might choose this setting whether the data warehouse contains historical data or a snapshot. Later, when you configure how to update individual target tables, you can determine whether to insert updated rows as new rows or use the updated information to modify existing rows in the target.

Data Driven

Exert finer control over how you flag rows for insert, delete, update, or reject. Choose this setting if rows destined for the same table need to be flagged on occasion for one operation (for example, update), or for a different operation (for example, reject). In addition, this setting provides the only way you can flag rows for reject.

Specifying Operations for Individual Target Tables

Once you determine how to treat all rows in the session, you also need to set update strategy options for individual targets. Define the update strategy options in the Transformations view on Mapping tab of the session properties.

You can set the following update strategy options:

Insert. Select this option to insert a row into a target table.

Delete. Select this option to delete a row from a table.

Update. You have the following options in this situation:

Update as Update. Update each row flagged for update if it exists in the target table.

Update as Insert. Insert each row flagged for update.

Update else Insert. Update the row if it exists. Otherwise, insert it.

Truncate table. Select this option to truncate the target table before loading data.