This field is used to define a query in SQL format, which will be used as an additional filter when executing the extraction of data to index. the fields of the database are expressed in the form of ABV.FIELD_i, where ABV is the abbreviation used for the table in the model, FIELD, the name of the field and i, the index (0 on single-sized fields). For example, it can be BPC.BPCNUM_0 for a BPCNUM field originating from the BPC abbreviation.