FreeTDS Development Group

["Schörk, Andreas" <andreas.schoerk AT infor.de>]

>a tool to reverse engineering (sniff) connections with 
>  the JDBC-ODBC driver and allow us to work out how some of
>  those nasty metadata calls work (I have a start on this 
>  locally)

at the moment the mixing of update-count delivering and resultset-delivering
statements
seems not to work right.
Splitting them up and executing separately seems to help. But it is only a
workaround.

Andreas

below the changed getCatalogs and getSchemas which make t005x (except t0054
in my environment) work.


    public java.sql.ResultSet getCatalogs()
             throws SQLException
    {
        // XXX We should really clean up all these temporary tables.
        String tmpName = "#t#" + UniqueId.getUniqueId();
        final String sql =
                " create table " + tmpName + "
" +
                " (
" +
                "    q  char(30) not null,
" +
                "    o  char(30) null,
" +
                "    n  char(30) null,
" +
                "    t  char(30) null,
" +
                "    r  varchar(255) null
" +
                " )
";
        final String sql2 = 
                " insert into " + tmpName + " EXEC sp_tables ' ', ' ', '%',
null ";
        final String selectString = 
                " select q from " + tmpName + "
" +
                "";
        java.sql.Statement stmt = connection.createStatement();
        java.sql.ResultSet rs;

        if ( stmt.execute( sql ) ) {
            throw new SQLException( "Internal error.  Confused" );
        }
        if ( null != ( rs = stmt.getResultSet() ) ) {
            // RMK 2000-06-11: test t0051 gets the result set here.

            // XXX we really need to figure out what the protocol is doing
here.
            // It appears that sometimes it returns an immediate result set
            //and sometimes it doesn't.

            return rs;
        }
        if ( stmt.execute( sql2 ) ) {
            throw new SQLException( "Internal error.  Confused" );
        }
        
        if ( null != ( rs = stmt.getResultSet() ) ) {

            // RMK 2000-06-11: test t0051 gets the result set here.

            // XXX we really need to figure out what the protocol is doing
here.
            // It appears that sometimes it returns an immediate result set
            //and sometimes it doesn't.

            return rs;
        }

        if ( !stmt.execute( selectString ) ) {
            throw new SQLException( "Internal error.  Confused" );
        }
        // now get the result set
        if ( null == ( rs = stmt.getResultSet() ) ) {
            throw new SQLException( "Internal error.  Confused" );
        }
        return rs;
    }
    public java.sql.ResultSet getSchemas() throws SQLException
    {
        // XXX We should really clean up all these temporary tables.
        String tmpName = "#t#" + UniqueId.getUniqueId();
        final String sql =
                " create table " + tmpName + "
" +
                " (
" +
                "    q  char(30) null,
" +
                "    o  char(30) not null,
" +
                "    n  char(30) null,
" +
                "    t  char(30) null,
" +
                "    r  varchar(255) null
" +
                " )
";
        final String sql2 = 
                " insert into " + tmpName + " EXEC sp_tables ' ', '%', ' ',
null ";
        final String sql3 = 
                " select TABLE_SCHEM=o from " + tmpName + "
" +
                "";
        java.sql.Statement stmt = connection.createStatement();
        java.sql.ResultSet rs;

        if ( stmt.execute( sql ) ) {
            throw new SQLException( "Internal error.  "
                     + "Unexpected result from stmt.execute(sql) "
                     + "inside of getSchemas" );
        }

        if ( stmt.getMoreResults() ) {
            throw new SQLException( "Internal error.  "
                     + "Was expecting an update count "
                     + "inside of getSchemas" );
        }
        else {
            int updateCount = stmt.getUpdateCount();
        }

        if ( stmt.execute( sql2 ) ) {
            throw new SQLException( "Internal error.  "
                     + "Unexpected result from stmt.execute(sql) "
                     + "inside of getSchemas" );
        }
        
        if ( stmt.execute( sql3 ) ) {
            rs = stmt.getResultSet();
        }
        else
            throw new SQLException( "Internal error.  "
                     + "Was expecting an result set "
                     + "inside of getSchemas" );

        return rs;
    }

-----Original Message-----
From: Stevenson, Chris (SSABSA) [mailto:chris AT ssabsa.sa.gov.au]
Sent: Mittwoch, 29. August 2001 04:36
To: TDS Development Group
Subject: [freetds] RE: jTds:, patches, not implemented fixes,
StringBuffer usage where to ??


First pass on a TODO/wish list for jTDS

- Further refactoring in Statement/ResultSet to support cursored 
  PreparedStatement and CallableStatement

- Updateable Cursored ResultSets (fairly straightforward)

- Check with spec on handling of datatypes in PacketRowResult

- Check with spec on handling of configuration properties

- Connection Pooling - this would require refactoring of the 
  TDS protocol classes

- Prefetch in cursored ResulSets (may improve performance)
 
- a tool to reverse engineering (sniff) connections with 
  the JDBC-ODBC driver and allow us to work out how some of
  those nasty metadata calls work (I have a start on this 
  locally)

> Hello,
> I just intergrated the actual jTDS version into my source and would like
to
> know how in the future the CVS is managed. I had to get rid of some not 
> implemented in the past and would like to send them.

If you send me the code directly I will see what I can do. Otherwise if 
you want to join in the development I can add you to the Developers
list on sourceforge (you will need to create a login first).

> Working with bigger statements the driver gets very slow in TDS 7.0  
> due to the usage of strings instead of StringBuffer.
>
> Also I would like to discuss the actual cursor concept. But this later.
>
> Andreas


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