/ modules / paradigms / Textual_InformixVerity.py 

 SYNOPSIS

     Textual_InformixVerity (table, idColumn, textColumn, cardinality,
         intraColumnField=None,
         mapping=TextUtils.mappings.nonAlphanumericToWhitespace,
         deleteList=TextUtils.deleteLists.keepAll)

         table
             A table to query, e.g., "holding".

         idColumn
             The table's identifier column (i.e., the column to be
             selected), e.g., "holding_id".

         textColumn
             The table column containing the text to search over
             (i.e., the column against which the constraint is to be
             placed), e.g., "subject_text".

         cardinality
             A Cardinality object representing the cardinality of
             'table' with respect to 'textColumn'.

         intraColumnField
             The intra-column field to restrict the search to, e.g.,
             "title".  The default value of None means the search is
             to be performed over the entire column.

         mapping
             A Python character mapping table (i.e., a string of
             length 256, indexed by ASCII character code) to process
             constraint text with.  Defaults to
             'nonAlphanumericToWhitespace', which maps
             non-alphanumeric characters to whitespace (i.e., to word
             separators).

         deleteList
             A string of zero or more characters to delete from
             constraint text.  The default is the empty string, which
             keeps all characters.

 DESCRIPTION

     Translates a textual constraint to an Informix Verity DataBlade
     function call of the form

         SELECT idColumn FROM table
             WHERE vts_contains(textColumn, 'op("W1", "W2", ...)')

     or

         SELECT idColumn FROM table
             WHERE vts_contains(textColumn,
                 'op("W1", "W2", ...)  intraColumnField')

     where 'op' is the Verity operator equivalent of the constraint
     operator.  ("W1", "W2", ...) is a sequence of one or more words
     formed from the constraint text T by 1) deleting from T any
     characters that appear in 'deleteList'; 2) mapping the remaining
     characters using 'mapping'; and 3) treating sequences of
     whitespace characters as word separators.

     The semantics of the "contains-all-words" operator will
     generally be correct only if the cardinality is "1" or "1?".  If
     the cardinality is "0+" or "1+", wrap this paradigm in an
     Adaptor_IndivisibleConcatenation paradigm.

     Exceptions thrown:

         no query words specified

 AUTHOR

     Greg Janee
     gjanee@alexandria.ucsb.edu

 HISTORY

     $Log: Textual_InformixVerity.py,v $
     Revision 1.2  2003/10/21 20:34:37  gjanee
     Minor (but critical) documentation change.

     Revision 1.1  2003/02/05 00:10:34  gjanee
     Initial revision