Units, Description and Detail are just character strings which are accessible in your program from dbquery. The Range is an expression which can be evaluated, to test if a value is legal. Information characterizing a 'seismic phase' observed at a particular station is saved here. However, the optional clauses are used by the more advanced operations like join and sort. The name may take the special form Anonymous , in which case a unique name will be generated.
Fields specifies the attributes which make up a row in the table, in the order in which they appear.
Fields in an actual record will be separated by spaces, to facilitate inspection with editors. However, backslash escapes are not recognized, so the actual character must appear in the schema file. The Separator clause will accept either just the field separator, or both the field and record separator. Description and Detail are short and verbose descriptions of the table, accessible through dbquery. The Primary, Alternate, and Foreign clauses specify the various keys for the table.