column-definition

1 column-name
2? FOR
2.1! COLUMN
2.2 system-column-name
3 data-type (1) 
4+ 
4? 
4 default-clause
4.0! GENERATED ALWAYS
4.0?
4.0 GENERATED BY DEFAULT
4.1 (2) 

4.1? 
4.1 identity-options
4.1 as-row-change-timestamp-clause
4 NOT NULL
4! NOT HIDDEN
4?
4 IMPLICITLY HIDDEN
4 column-constraint
4 FIELDPROC external-program-name
4.1? 
4.1 (
4.1.1+ ,
4.1.1 constant
4.1.2 )
4 datalink-options (3) 
5 (4) 


data-type

1 built-in-type
1 distinct-type-name