Occasionally a particular mask may be used as a temporary bug workaround. Otherwise use at your own risk. A schema is similar to a C struct declaration with the struct keyword omitted. A schema specifies names and types for the fields in a database record. A C unsigned long variable whose string representation is a date.
Schemas are themselves types.
In this case the field value is a string key that is used to match the first field in the referenced schema. The main schema input is the data command line argument if specified. Otherwise schema input file names are determined by the schema name with an optional .db suffix. The default action lists each selected record as it appears in the databse. Evaluated once before the traversal begins.