Обсуждение: Re: [PATCHES] DatabaseMetadata patch

Here is a patch for DatabaseMetaData to show precision properly.  It is
from Mark Lillywhite.  I am adding to the patch queue.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026
Index: org/postgresql/jdbc2/DatabaseMetaData.java
===================================================================
RCS file: /cvs/pgjdbc71/org/postgresql/jdbc2/DatabaseMetaData.java,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -r1.1 -r1.2
--- org/postgresql/jdbc2/DatabaseMetaData.java    2001/10/04 05:01:32    1.1
+++ org/postgresql/jdbc2/DatabaseMetaData.java    2001/10/23 09:44:30    1.2
@@ -1932,7 +1932,19 @@

     tuple[7] = null;    // Buffer length

-    tuple[8] = "0".getBytes();    // Decimal Digits - how to get this?
+        // Decimal digits = scale
+        // From the source (see e.g. backend/utils/adt/numeric.c,
+        // function numeric()) the scale and precision can be calculated
+        // from the typmod value. mark@plasticsoftware.com.au
+        if (typname.equals("numeric") || typname.equals("decimal"))
+        {
+          int attypmod = r.getInt(8);
+          tuple[8] =
+            Integer.toString((attypmod & 0xffff) - VARHDRSZ).getBytes();
+        }
+        else
+          tuple[8] = "0".getBytes();
+
     tuple[9] = "10".getBytes();    // Num Prec Radix - assume decimal

     // tuple[10] is below

Bruce Momjian <pgman@candle.pha.pa.us> writes:
> +          tuple[8] =
> +            Integer.toString((attypmod & 0xffff) - VARHDRSZ).getBytes();

In the backend sources, we subtract VARHDRSZ *first* and then AND with FFFF.
Not sure if this will ever yield a different result, but I'd say it
should be kept consistent ...

            regards, tom lane

The patch is missing the corresponding fix for
jdbc1/DatabaseMetaData.java.  Can you resubmit the patch with a fix for
both occurances of the problem?  Otherwise the fix looks fine.

thanks,
--Barry

Bruce Momjian wrote:

> Here is a patch for DatabaseMetaData to show precision properly.  It is
> from Mark Lillywhite.  I am adding to the patch queue.
>
>
>
> ------------------------------------------------------------------------
>
> Index: org/postgresql/jdbc2/DatabaseMetaData.java
> ===================================================================
> RCS file: /cvs/pgjdbc71/org/postgresql/jdbc2/DatabaseMetaData.java,v
> retrieving revision 1.1
> retrieving revision 1.2
> diff -u -r1.1 -r1.2
> --- org/postgresql/jdbc2/DatabaseMetaData.java    2001/10/04 05:01:32    1.1
> +++ org/postgresql/jdbc2/DatabaseMetaData.java    2001/10/23 09:44:30    1.2
> @@ -1932,7 +1932,19 @@
>
>      tuple[7] = null;    // Buffer length
>
> -    tuple[8] = "0".getBytes();    // Decimal Digits - how to get this?
> +        // Decimal digits = scale
> +        // From the source (see e.g. backend/utils/adt/numeric.c,
> +        // function numeric()) the scale and precision can be calculated
> +        // from the typmod value. mark@plasticsoftware.com.au
> +        if (typname.equals("numeric") || typname.equals("decimal"))
> +        {
> +          int attypmod = r.getInt(8);
> +          tuple[8] =
> +            Integer.toString((attypmod & 0xffff) - VARHDRSZ).getBytes();
> +        }
> +        else
> +          tuple[8] = "0".getBytes();
> +
>      tuple[9] = "10".getBytes();    // Num Prec Radix - assume decimal
>
>      // tuple[10] is below
>
>
> ------------------------------------------------------------------------
>
>
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> The patch is missing the corresponding fix for
> jdbc1/DatabaseMetaData.java.  Can you resubmit the patch with a fix for
> both occurances of the problem?  Otherwise the fix looks fine.

I have applied the jdbc2 version.  It would be nice to have a jdbc1
version too.  Thanks.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

JDBC1 patch attached. I don't have a JDBC1 environment (that I know of)
so I haven't even compiled this... sorry :(

I also attach a very small patch to correct my email address in the JDBC
2 patch. Apply it or not, it's not important, I just noticed it.

Thanks again
Cheers
Mark

> I have applied the jdbc2 version.  It would be nice to have a jdbc1
> version too.  Thanks.

This was applied a while ago.  Thanks.

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> JDBC1 patch attached. I don't have a JDBC1 environment (that I know of)
> so I haven't even compiled this... sorry :(
>
> I also attach a very small patch to correct my email address in the JDBC
> 2 patch. Apply it or not, it's not important, I just noticed it.
>
> Thanks again
> Cheers
> Mark
>
> > I have applied the jdbc2 version.  It would be nice to have a jdbc1
> > version too.  Thanks.
>

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--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026