How to use a DataSource based on condition being true?

问题

I'm currently trying to build a query that uses a datasource based on a particular condition being true. Say "if value == 1, use datasource 1. If value == 2, use datasource 2.

These tables are already a couple of levels into my datasources.

Haven't been able to find info on this anywhere!

回答1:

You did not specify the tables and relations, but using these datasources as an example:

• CustTable
  • CustTrans (JoinMode: ExistsJoin)
  • CustInvoiceJour (JoinMode: ExistsJoin)

Suppose you want to exists join on either CustTrans or CustInvoiceJour?

This can be accomplished by enabling and disabling the corresponding datasources:

custTable_ds.query().datasourceTable(tableNum(CustTrans)).enabled(!useInvoice);
custTable_ds.query().datasourceTable(tableNum(CustInvoiceJour )).enabled(useInvoice);

This should be done before super() in the executeQuery method of the CustTable datasource.

来源：https://stackoverflow.com/questions/12256065/how-to-use-a-datasource-based-on-condition-being-true