[Firebird-odbc-devel] incorrect NULL indicator

[Michele C. <m....@it...>]

Hi all and sorry for my poor english.

I tested OdbcJdbc driver for Firebird. Great work !!!!
I fave found an incorrect reslt for NULL indicator.
Here there is an example:

CREATE TABLE XX
(
   YY	INTEGER,
   YYSTR	VARCHAR(10)
);

COMMIT WORK;

INSERT INTO XX (YY, YYSTR) VALUES (NULL, NULL);

COMMIT;

 From a test MFC Application I test NULL status of XX and YYSTR fields:
XX is NULL (correctly) and YYSTR is NOT NULL (wrong!!!).

All work fine if table's fields are all INTEGER such as above example:

CREATE TABLE XX2
(
   YY	INTEGER,
   YY2	INTEGER
);

COMMIT WORK;

INSERT INTO XX2 (YY, YY2) VALUES (NULL, NULL);

COMMIT;
 From a test MFC Application, in this case, YY is NULL and YY2 is NULL.

So I have done some debuggging for investigating the problem.
In the first case, into IscResultSet::next() after
	int ret = statement->connection->GDS->_dsql_fetch (statusVector, 
&statement->statementHandle, dialect, *sqlda);

I have found that sqlind for the second XSQLVAR (field YYSTR) is 0.
So or isc_dsql_fetch have a bug or there was a buffer overflow.
Into Sqlda::allocBuffer I saw that indicators buffers were
allocated at the end of data buffers.
Is an overflow of YYSTR varying fetching that overwrite YY indicator 
buffer? I don't know the OdbcJdbc soruce code, so my investigation
halted here.
I hope this is useful.




My ENV is:

VS 6 SP5
MFC Application
Win2k Pro SP4
Firebird 1.5 RC7 and RC8
OdbcJdbc (snapshot 2003-12-29)