Getting MySQL column comment metadata?

Ruby
1

Hi All,

How do I go about getting the “Comments” metadata–the one I type via
MySQL Administrator, for example–associated with a MySQL column?

I have been able to pull metadata from both ActiveRecord and DBI but
cannot seem to find this added bit of info.

Thanks.
Mario T. Lanza

2

I’m not sure what you are asking, so I will take a guess…

If you want to access the metadata on all tables in db “MY_DB” you can
do something like…

SELECT table_name, table_type, engine FROM INFORMATION_SCHEMA.tables
WHERE table_schema = ‘MY_DB’ ORDER BY table_type ASC, table_name DESC;

Or you can just use “describe table_name;” to get data on that specific
table.

-mike

3

On Sun, 19 Aug 2007 23:33:35 +0900, Mario T. Lanza wrote:

Hi All,

How do I go about getting the “Comments” metadata–the one I type via
MySQL Administrator, for example–associated with a MySQL column?

I have been able to pull metadata from both ActiveRecord and DBI but
cannot seem to find this added bit of info.

This doesn’t appear to be implemented directily in MySQL’s C API.
Certainly it’s not implemented in the direct MySQL Ruby API (see http://
MySQL/Ruby and have a look at fetch_fields and the
Mysql::Field class). Since DBD::Myql uses fetch_fields to determine what
metadata is available, it’s not available in dbi. I don’t know about
ActiveRecord, but I would expect the same thing.

The only way I know of to get this information is by running a “show
full
columns from TABLENAME” or using INFORMATION_SCHEMA. (Well, there’s
“show
create table” too, but that requires parsing – why use that when you
have “show full columns”)

–Ken

4

Thanks for the help. This is useful but I would like to use a library
designed for providing this sort of information without regard to the
underlying database. I attempted to clarify my original request, by
posting:

http://www.ruby-forum.com/topic/122032#544080

Thanks again.

5

The column I was referring to appears in the attached screenshot. Far
right. Notice “First name”.