Fetching Component Tables
In SQL queries that select data from database tables AND component tables, you can influence the order in which these tables are queried. Relevant are:
This is determined by the Rowset size hint setting on the State tab page of the Components window.
In SQL queries that select data from one or more component tables, this is how the Rules Engine determines which table to query first:
Then the remaining SQL statement is processed.
For each fetched record returned from the remaining SQL statement, the values are substituted in the SQL statement sent to the component.
This workflow is illustrated in the "Order of Querying Tables" flowchart.
When to use
Using rowset size hints if querying the table component can take a lot of time, depending on the number of returned records.
Change the QUERY_ORDER_TURNING_POINT parameter only after thorough testing.
Use BenchMark's Tracer to monitor the order of SQL statements, and the conditions within the statements that the Rules Engine executes. The Tracer also displays INVOKE statements sent to components.
To have a table component support rowset size hints:
The ROWSETSIZE method has the same input parameter(s) as the QUERYEXE method. If 'Extended query conditions' is selected, this is an XML document.
To change the Query Order Turning Point Rules Engine parameter: