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