• SYNOPSIS
• DESCRIPTION
• SQL Operations
• Uses of attributes
• Sources for Help
• The Development Project
• AUTHORS AND COPYRIGHT

Why do some operations performing positioned update and delete fail when AutoCommit is on?
For example, the following code snippet fails:

$sth = $dbh->prepare(
"SELECT * FROM ORDERS WHERE user_id < 5 FOR UPDATE OF comment");
$sth->execute;
while (@res = $sth->fetchrow_array) {
    $dbh->do("UPDATE ORDERS SET comment = 'Wonderful' WHERE 
    CURRENT OF $sth->{CursorName}");
}

• Using AutoCommit = 0
  If yours is default to AutoCommit on, you can put the snippet within a block:

  {
      $dbh->{AutoCommit} = 0;
      # same actions like above ....
      $dbh->commit;
  }
  

• Using $dbh->{ib_softcommit} = 1
  This driver-specific attribute is available as of version 0.30. You may want to look at t/40cursoron.t to see it in action.

Nested statement handles break under AutoCommit mode.
The same explanation as above applies. The workaround is also much alike:

{
    $dbh->{AutoCommit} = 0;
    $sth1 = $dbh->prepare("SELECT * FROM $table");
    $sth2 = $dbh->prepare("SELECT * FROM $table WHERE id = ?");
    $sth1->execute;

    while ($row = $sth1->fetchrow_arrayref) {
        $sth2->execute($row->[0]);
        $res = $sth2->fetchall_arrayref;
    }
    $dbh->commit;
}

Why do placeholders fail to bind, generating unknown datatype error message?
You can't bind a field name. The following example will fail:

$sth = $dbh->prepare("SELECT (?) FROM $table");
$sth->execute('user_id');

SELECT * FROM $table WHERE UPPER(author) LIKE UPPER(? COLLATE FR_CA);

How to do automatic increment for a specific field?
Create a generator and a trigger to associate it with the field. The following example creates a generator named PROD_ID_GEN, and a trigger for table ORDERS which uses the generator to perform auto increment on field PRODUCE_ID with increment size of 1.

$dbh->do("CREATE GENERATOR PROD_ID_GEN");
$dbh->do(
"CREATE TRIGGER INC_PROD_ID FOR ORDERS
BEFORE INSERT POSITION 0
AS BEGIN
  NEW.PRODUCE_ID = GEN_ID(PROD_ID_GEN, 1);
END");

How can I perform LIMIT clause as I usually do in MySQL?
LIMIT clause let users to fetch only a portion rather than the whole records as the result of a query. This is particularly efficient and useful for paging feature on web pages, where users can navigate back and forth between pages. Using InterBase (Firebird is explained later), this can be emulated by writing a stored procedure. For example, to display a portion of table_forum, first create the following procedure:

CREATE PROCEDURE PAGING_FORUM (start INTEGER, num INTEGER)
RETURNS (id INTEGER, title VARCHAR(255), ctime DATE, author VARCHAR(255))
AS 
DECLARE VARIABLE counter INTEGER;
BEGIN
  counter = 0;
  FOR SELECT id, title, ctime, author FROM table_forum ORDER BY ctime
     INTO :id, :title, :ctime, :author
  DO
  BEGIN
     IF (counter = :start + :num) THEN EXIT;
     ELSE
        IF (counter >= :start) THEN SUSPEND;
     counter = counter + 1;          
  END
END !!
SET TERM ; !!

# fetch record 1 - 5:
$res = $dbh->selectall_arrayref("SELECT * FROM paging_forum(0,5)");

# fetch record 6 - 10: 
$res = $dbh->selectall_arrayref("SELECT * FROM paging_forum(5,5)");

$sth = $dbh->prepare(
"EXECUTE PROCEDURE paging_forum(5,5) RETURNING_VALUES :id, :title, :ctime, 
:author");

SELECT FIRST 10 SKIP 30 * FROM table_forum;

How can I use the date/time formatting attributes?
Those attributes take the same format as the C function strftime()'s. Examples:

$attr = {
   ib_timestampformat => '%m-%d-%Y %H:%M',
   ib_dateformat => '%m-%d-%Y',
   ib_timeformat => '%H:%M',
};

$sth = $dbh->prepare($stmt, $attr);
# followed by execute() and fetch(), or:

$res = $dbh->selectall_arrayref($stmt, $attr);

Can I set the date/time formatting attributes between prepare and fetch?
No. ib_dateformat, ib_timeformat, and ib_timestampformat can only be set during $sth->prepare. If this is a problem to you, let me know, and probably I'll add this capability for the next release.

Can I change ib_dialect after DBI->connect ?
No. If this is a problem to you, let me know, and probably I'll add this capability for the next release.

Why do execute(), do() method and rows() method always return -1 upon a successful operation?
Incorrect question. $sth->rows returns the number of fetched rows after a successful SELECT. But it's true that for statements other than SELECT, it returns -1, because I don't know how to get the number of affected rows :-}

I can't find the answer for my question here, where should I direct my question?
For questions regarding InterBase itself, you can join the InterBase mailing list at http://groups.yahoo.com/group/ib-support/, or if it is not enough, I believe there are some commercial supports available out there. http://www.ibphoenix.com/ is a good place to check. For questions about DBD::InterBase, try to look for the answer on DBI man page, and DBI::FAQ. If your question is still unanswered, you can drop me message or you can post your question to the DBI users mailing list.

How can I join the development project?
The project is hosted at sourceforge.net. So send me your sourceforge username, and let me know what areas you are interested in. SourceForge.net project page: http://sourceforge.net/projects/dbi-interbase/

Is there a mailing list for DBD::InterBase?
Please join dbi-interbase-devel mailing list at http://lists.sourceforge.net/mailman/listinfo/dbi-interbase-devel/

Where can I get the latest release of DBD::InterBase ?
http://dbi.interbase.or.id/ (stable and development release), and http://www.cpan.org/modules/by-module/DBD/ (stable release only).