Обсуждение: Error in DatabaseMetaData TableColumn lenght.dec information
Hi, I whish to report a erroneous information returned by DatabaseMetaData.getColumns() method.
This happens with ResultSet's column (7) COLUMN_SIZE and (9) DECIMAL_DIGITS ,
when DatabaseMetaData.getColumns() inform about a VIEW with columns formed with :
coalesce , case or numeric operations over DECIMAL fields.
Suppose
CREATE TABLE A ( f1 DEC(6,3), f2 dec(6,3) );
CREATE VIEW B as ( select ( f1 + f2 ) as f from a;
Then DatabaseMetaData.getColumns() returns:
VIEW B
F NUMERIC( 65535 , -65531 )
This error its very molest because if you are trying to do CodeGeneration tools from DatabaseMetaData , you get lost.
Any suggestion will be appreciated.
Dario V. Fassi
SISTEMATICA ingenieria de software srl
Ituzaingo 1628 (2000) Rosario, Santa Fe, Argentina.
Tel / Fax: +54 (341) 485.1432 / 485.1353
This happens with ResultSet's column (7) COLUMN_SIZE and (9) DECIMAL_DIGITS ,
when DatabaseMetaData.getColumns() inform about a VIEW with columns formed with :
coalesce , case or numeric operations over DECIMAL fields.
Suppose
CREATE TABLE A ( f1 DEC(6,3), f2 dec(6,3) );
CREATE VIEW B as ( select ( f1 + f2 ) as f from a;
Then DatabaseMetaData.getColumns() returns:
VIEW B
F NUMERIC( 65535 , -65531 )
This error its very molest because if you are trying to do CodeGeneration tools from DatabaseMetaData , you get lost.
Any suggestion will be appreciated.
Best regards,
Dario V. Fassi
SISTEMATICA ingenieria de software srl
Ituzaingo 1628 (2000) Rosario, Santa Fe, Argentina.
Tel / Fax: +54 (341) 485.1432 / 485.1353
On Fri, 2 Jul 2004, Dario V. Fassi wrote: > Hi, I whish to report a erroneous information returned by > DatabaseMetaData.getColumns() method. > > Suppose > > CREATE TABLE A ( f1 DEC(6,3), f2 dec(6,3) ); > CREATE VIEW B as ( select ( f1 + f2 ) as f from a; > > Then DatabaseMetaData.getColumns() returns: > > VIEW B > F NUMERIC( 65535 , -65531 ) > I've modified the cvs version of the driver to return numeric(1000,1000) which is the maximum precision and scale you are allowed to define. A more complete solution is outside the realm of the JDBC driver. Kris Jurka
Kris Jurka <books@ejurka.com> writes:
> I've modified the cvs version of the driver to return numeric(1000,1000)
> which is the maximum precision and scale you are allowed to define. A
> more complete solution is outside the realm of the JDBC driver.
That doesn't sound like a usable answer at all. A client that believes
this result will think that the value cannot contain any digits to the
left of the decimal point --- which is certainly not so.
Does the JDBC spec allow you to return NULL for these entries? That's
what we recently fixed the information_schema views to do for
unconstrained numeric columns.
regards, tom lane
Kris Jurka wrote:
On Fri, 2 Jul 2004, Dario V. Fassi wrote:Hi, I whish to report a erroneous information returned by DatabaseMetaData.getColumns() method. Suppose CREATE TABLE A ( f1 DEC(6,3), f2 dec(6,3) ); CREATE VIEW B as ( select ( f1 + f2 ) as f from a; Then DatabaseMetaData.getColumns() returns: VIEW B F NUMERIC( 65535 , -65531 )I've modified the cvs version of the driver to return numeric(1000,1000) which is the maximum precision and scale you are allowed to define. A more complete solution is outside the realm of the JDBC driver. Kris Jurka
Kris,
A return value of numeric(1000,1000) , is far better than numeric(65535,-65531) , but this mean a number with all the presicion in the fractional part and is not very usefull.
Why not a more login value like "Numeric(100,50)" , yet oversized but more appropiate.
Can you imagine a number with 1000 digit's presicion, it's impractical and undisplayable.
Dario Fassi.
A return value of numeric(1000,1000) , is far better than numeric(65535,-65531) , but this mean a number with all the presicion in the fractional part and is not very usefull.
Why not a more login value like "Numeric(100,50)" , yet oversized but more appropiate.
Can you imagine a number with 1000 digit's presicion, it's impractical and undisplayable.
Dario Fassi.
On Sat, 10 Jul 2004, Tom Lane wrote: > Kris Jurka <books@ejurka.com> writes: > > I've modified the cvs version of the driver to return numeric(1000,1000) > > which is the maximum precision and scale you are allowed to define. A > > more complete solution is outside the realm of the JDBC driver. > > That doesn't sound like a usable answer at all. A client that believes > this result will think that the value cannot contain any digits to the > left of the decimal point --- which is certainly not so. I blew this one. For some reason I was thinking 1000, 1000 was 1000 to the left and right of the decimal. > Does the JDBC spec allow you to return NULL for these entries? That's > what we recently fixed the information_schema views to do for > unconstrained numeric columns. No, the method returns "int" which is a primitive type and therefore can't be null. Maybe -1? I'm not sure what the best answer is. Kris Jurka