David, On Tuesday 25 May 2004 03:05, you wrote: > I have an application using Lucene 1.3 final. > > In this application, I am loading data where the main text for each > document is stored into a "body" field, a couple of other internal fields, > and basically some "meta-data fields" driven by the data being loaded, > which can created Lucene fields like M1, M2, M3, ... > > Not every document has every meta-data field present, for example, one > document may have M1, M5, M6, another might just have M1, M2, M3. It is > also possible for the meta-data field value to be just the empty string. > > The presence of a meta-data field has meaning to the application. In > general, it is not known in advance what meta-data fields are present, but > it is generally a smallish number (< 100). > > There is a requirement for the user to be able to retrieve all documents > which have a particular meta-data field present. > > I can't see anyway of doing this with the query parser. Is there a way of > doing this? ie, retrieve all documents which have a specific field set. > > I seems to me I need to create a new tokenized unstored field called > something like "meta-data-fields" for each document, which contains what > meta-data field names are present for that document. In the above > example, one document could have the value "M1 M5 M6", the other "M1 M2 > M3". > > Does this seem reasonable? Is there any way of doing this without > introducing a new field?
Normally an empty string does not result in indexed terms, so there is no way to find out about the existence of an indexed field in that case, except by using more information. Using an extra field that mentions the field names of all other fields will solve your problem. In practice, such a field is also quite handy for statistics/debugging, so I'd tokenize, index and store it. Once it's indexed, it can be queried as any other field. Kind regards, Ype --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
