[Info-ingres] ALTER TABLE...ALTER COLUMN bug, or no?

[Roy Hann]

It seems that changing the size of a character column without explicitly
specifying NOT NULL does not preserve non-nullability. This is
seen in 10.1 and 10.2, on Windows and Solaris (at least).

Keeping in mind the following passage from the SQL Guide about ALTER
TABLE...ALTER COLUMN: "Change the size of a character column to
preserve the existing default_clause, null_clause, column_constraint,
and collation_name", is it a bug? And if it is a bug is it an error
in the code or the documentation? 

I say the documentation describes the reasonable behaviour.

Example:

* create table foo ( name varchar(20) not null ) \g
Executing . . .

continue
* commit \g
Executing . . .

continue
* help foo \g
Executing . . .

Name:                 foo
Owner:                roy
Created:              24-jan-2018 19:13:34
Type:                 user table
Version:              II10.0

Column Information:
                                                                          Key
Column Name                      Type               Length Nulls Defaults Seq
name                             varchar                20   no      no

continue
* alter table foo alter column name varchar(30) \g
Executing . . .

continue
* help foo \g
Executing . . .

Name:                 foo
Owner:                roy
Created:              24-jan-2018 19:13:34
Location:             ii_database
Type:                 user table
Version:              II10.0

Column Information:
                                                                  Key
Column Name              Type               Length Nulls Defaults Seq
name                     varchar                30  yes    null

Secondary indexes:    none

continue
* rollback \g
Executing . . .

continue
* alter table foo alter column name varchar(30) not null \g
Executing . . .

continue
* help foo \g
Executing . . .

Name:                 foo
Owner:                roy
Created:              24-jan-2018 19:13:34
Type:                 user table
Version:              II10.0

Column Information:
                                                                          Key
Column Name                      Type               Length Nulls Defaults Seq
name                             varchar                30   no      no

continue
*