6. A non-transitory computer program storage device readable by a computer, tangibly embodying a program of instructions executable by the computer to perform a method for dynamically querying structured and unstructured data repositories, the method comprising: maintaining a unified index associated with a structured data repository an unstructured data repository; receiving a unified query of keywords including a first keyword for querying the structured data repository and a second keyword for querying the unstructured data repository; first querying one of the structured data repository and the unstructured data repository with a keyword; if first querying the structured data repository, then matching the unified index to first querying the results with the first keyword, and using unified index matches to limit second querying of the unstructured data repository with the second keyword; and if first query the unstructured data repository, then matching the unified index to first querying results with the second keyword, and using unified index matches to limit second querying of the structured data repository with the first keyword, wherein the first querying of the one of the structured data repository and the unstructured data repository is decided at query time using occurrence statistics for the keywords.
6. A non-transitory computer program storage device readable by a computer, tangibly embodying a program of instructions executable by the computer to perform a method for dynamically querying structured and unstructured data repositories, the method comprising: maintaining a unified index associated with a structured data repository an unstructured data repository; receiving a unified query of keywords including a first keyword for querying the structured data repository and a second keyword for querying the unstructured data repository; first querying one of the structured data repository and the unstructured data repository with a keyword; if first querying the structured data repository, then matching the unified index to first querying the results with the first keyword, and using unified index matches to limit second querying of the unstructured data repository with the second keyword; and if first query the unstructured data repository, then matching the unified index to first querying results with the second keyword, and using unified index matches to limit second querying of the structured data repository with the first keyword, wherein the first querying of the one of the structured data repository and the unstructured data repository is decided at query time using occurrence statistics for the keywords. 7. The non-transitory computer program storage device of claim 6 , wherein: the unified index stores occurrence statistics for the keywords; the structured data repository comprises a structured database including table names and dimensional values of tables that include the first keyword; and the unstructured data repository comprises unstructured text that includes the second keyword.