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Generate Filters

The Generate Filters dialog box allows you to define a row filter on one table in a merge publication; replication then automatically extends the filter to other tables that are related through foreign key relationships. For example, if you define a filter on a customer table so that it only contains data on French customers, replication extends that filter so that related orders and order details tables contain only information related to French customers.

Options

This dialog box involves a three-step process to create a row filter on a table. The filter is then extended to the tables related to the filtered table through primary key and foreign key relationships. For example, given the three tables Customer, SalesOrderHeader, and SalesOrderDetail, with a relationship between Customer and SalesOrderHeader, and a relationship between SalesOrderHeader and SalesOrderDetail, apply a row filter to Customer, and replication extends that filter to SalesOrderHeader and SalesOrderDetail.

  1. Select the table to filter.

    Select a table from the drop-down list box. Tables appear in the list box only if they were selected on the Articles page.

  2. Complete the filter statement to identify which table rows Subscribers will receive.

    Define a new filter statement. The Columns list box lists all the columns that you are publishing from the table you selected in Select the table to filter. The Filter statement text area includes the default text, which is in the form of:

    SELECT <published_columns> FROM [tableowner].[tablename] WHERE

    This text cannot be changed; type the filter clause after the WHERE keyword using standard Transact-SQL syntax.

    Important

    For performance reasons, we recommended that you not apply functions to column names in parameterized row filter clauses, such as LEFT([MyColumn]) = SUSER_SNAME(). If you use HOST_NAME in a filter clause and override the HOST_NAME value, it might be necessary to convert data types using CONVERT. For more information about best practices for this case, see the section "Overriding the HOST_NAME() Value" in the topic Parameterized Row Filters.

  3. Specify how many subscriptions will receive data from this table.

    Microsoft SQL Server 2005 and later versions only. Merge replication allows you to specify the type of partitions that are best suited to your data and application. If you select A row from this table will go to only one subscription, merge replication sets the nonoverlapping partitions option. Nonoverlapping partitions work in conjunction with precomputed partitions to improve performance, with nonoverlapping partitions minimizing the upload cost associated with precomputed partitions. The performance benefit of nonoverlapping partitions is more noticeable when the parameterized filters and join filters used are more complex. If you select this option, you must ensure that the data is partitioned in such a way that a row cannot be replicated to more than one Subscriber. For more information, see the section "Setting 'partition options'" in the topic Parameterized Row Filters.

After you have added a filter, click OK to exit and close the dialog box. The filter you specified is parsed and run against the table in the SELECT clause. If the filter statement contains syntax errors or other problems, you will be notified and will be able to edit the filter statement.

After the statement is parsed, replication creates the necessary join filters. If you have not yet configured the Distributor for the Publisher against which this wizard is running, you are prompted to configure it.