Description of a property in spec must correspond to DB TABLE COLUMN COMMENT

[SOHELAHMED7]

Also ensure COMMENT (description in spec) is preserved while altering the column

This issue will automatically fix following bug: comments are lost when altering a column

Test cases:

• new column - create comment
• existing column - add comment to a column
• existing column - remove comment from a column
• existing column - edit comment on a column