7. A multi-source search data processing system configured for multi-source searching for a data driven application, the system comprising: a host computer comprising memory and at least one processor; an application server executing in the host computer; a composition tool hosted by the application server, the composition tool defining a form for a data driven application, the form comprising a plurality of user interface controls corresponding to respectively to different fields in different data sources, generating a single search index for the form, the single search index including the different fields referenced in the form and also at least one data operation for the different fields referenced in the form, and coupling the form with a search user interface comprising a search control configured to accept at least one query term, the search control comprising a text control configured to link to one or more of the different fields of the single search index; and, a search service, the search service directing during execution of the data driven application in the application server a search engine query of the selection of the different fields in the single search index and not the different data sources according to the at least one query term provided in the search user interface without first requiring a join operation joining the different data sources.
7. A multi-source search data processing system configured for multi-source searching for a data driven application, the system comprising: a host computer comprising memory and at least one processor; an application server executing in the host computer; a composition tool hosted by the application server, the composition tool defining a form for a data driven application, the form comprising a plurality of user interface controls corresponding to respectively to different fields in different data sources, generating a single search index for the form, the single search index including the different fields referenced in the form and also at least one data operation for the different fields referenced in the form, and coupling the form with a search user interface comprising a search control configured to accept at least one query term, the search control comprising a text control configured to link to one or more of the different fields of the single search index; and, a search service, the search service directing during execution of the data driven application in the application server a search engine query of the selection of the different fields in the single search index and not the different data sources according to the at least one query term provided in the search user interface without first requiring a join operation joining the different data sources. 10. The system of claim 7 , wherein at least one of the different data sources is accessible through an intermediate business object.