Add support for GENERATED Columns

[altmannmarcelo]

Description

Add support for https://dev.mysql.com/doc/refman/8.4/en/create-table-generated-columns.html

Example functions:

  field_c int GENERATED ALWAYS AS (((nullif(field_a,_utf8mb4'') is null) and (nullif(field_b,_utf8mb4'') is null))) STORED,
  field_a tinyint(1) GENERATED ALWAYS AS (if((((field_b = _utf8mb4'') or (field_c is null)) and (field_d is null) and (field_f is null) and (field_g <> _utf8mb4'') and (field_h is not null)),_utf8mb4'1',_utf8mb4'0')) STORED,

Change in user-visible behavior

Requires documentation change