Обсуждение: BUG #1656: ResultSetMetaData.getColumnDisplaySize() returns value -1

The following bug has been logged online:

Bug reference:      1656
Logged by:          Sergio Lob
Email address:      sergio_lob@iwaysoftware.com
PostgreSQL version: 8.0.1
Operating system:   Linux edared30 2.4.21-27.0.4.ELsmp #1 SMP Sat Apr 16
18:43:06 EDT 2005 i686 i686
Description:        ResultSetMetaData.getColumnDisplaySize() returns value
-1
Details:

ResultSetMetaData.getColumnDisplaySize() returns value -1 for several
columns of answer set generated by DatabaseMetaData.getTables() method.

Columns 1,4 and 5 of answer set (columns "table_cat", "table_type", and
"remarks" respectively) are described to be of length -1. The other 2
columns of the answer set (columns 2 & 3) are described to be of length 64,
which makes more sense.

Is there a reason why -1 is returned for these columns?
Additionally, I don't understand why the data type of column 1 is described
as "OTHER", as opposed to all the other columns, which are of type "VARCHAR"
(attained through ResultSetMetaData.getColumnType() method).

Thanks, Sergio Lob

On Tue, 10 May 2005, Sergio Lob wrote:

> Bug reference:      1656
> PostgreSQL version: 8.0.1
> Description:        ResultSetMetaData.getColumnDisplaySize() returns value
> -1
> Details:
>
> ResultSetMetaData.getColumnDisplaySize() returns value -1 for several
> columns of answer set generated by DatabaseMetaData.getTables() method.

ResultSetMetaData.getColumnDisplaySize() returns -1 for any column that
has an unknown size.  Consider the REMARKS column of getTables().  This
data comes from the system's pg_description.description column which is of
type "text".  There is no defined length for this, so we have decided to
return -1.

> Additionally, I don't understand why the data type of column 1 is described
> as "OTHER", as opposed to all the other columns, which are of type "VARCHAR"
> (attained through ResultSetMetaData.getColumnType() method).
>

TABLE_CAT is generated by an untyped "SELECT NULL", we should probably
cast this to name, or report the currently connected database name here.

Kris Jurka