column-definition 1 column-name 2? FOR 2.1! COLUMN 2.2 system-column-name 3 data-type (1) 4 (2) 5+ 5? 5 default-clause 5.0! GENERATED ALWAYS 5.0? 5.0 GENERATED BY DEFAULT 5.1 (3) 5.1? 5.1 identity-options 5.1 as-row-change-timestamp-clause 5 NOT NULL 5! NOT HIDDEN 5? 5 IMPLICITLY HIDDEN 5 column-constraint 5 FIELDPROC external-program-name 5.1? 5.1 ( 5.1.1+ , 5.1.1 constant 5.1.2 ) 5 datalink-options (4) data-type 1 built-in-type 1 distinct-type-name