I just discovered recently that there is no way to do a case-insensitive search using DbQueryPlugin which leverages DbCacheContrib. In creating TWikiApps, we can not expect users to keep cases straight when entering search terms. So lack of case-insenstive option greatly restricts usefulness of DbCacheContrib in creating applications.
As an aside, and I realize this is a separate-but-related feature request, it would be nice to provide users the ability to do keyword search in conjuction with DbCacheContrib for the same reasons as discussed in TWiki:Codev.RegexSearchWithEmbeddedKeywordSearch
. I mention this here in case, while rummaging around the code of DbCacheContrib, you have some ideas of how to address this need as well.
Added lc and uc operators for case conversion, as well as generalising the parser to support field-field comparisons.