Identity Insert with SQLOLEDB from Perl

Question

I have a simple code sample here which throws an error on the SQL INSERT statement. It creates a table with a single integer identity column and then tries to force a value into it. My real world problem is more complex, but this distills the error I'm getting.
I can run the SQL statements from SQL Server Management Studio into the same database using the same credentials without issue.
use DBI;
use strict;
use warnings;
my $SQL_dbh;
my $SQL_sth;
my $tb = "testtb";
my $cnstr = "DBI:ADO:Provider=SQLOLEDB.1;
             Persist Security Info=False;
             User ID=<user id>;
             PWD=<password>;
             Initial Catalog=<database>;
             Data Source=<instance>;";
$SQL_dbh = DBI->connect($cnstr) || die "$DBI::errstr";
$SQL_sth = $SQL_dbh->prepare("create table $tb (col1 int identity(1,1))") || die "$DBI::errstr";
$SQL_sth->execute() || die "$DBI::errstr";
$SQL_sth = $SQL_dbh->prepare("set identity_insert $tb ON") || die "$DBI::errstr";
$SQL_sth->execute() || die "$DBI::errstr";
$SQL_sth = $SQL_dbh->prepare("insert into $tb (col1) values (4)") || die "$DBI::errstr";
$SQL_sth->execute() || die "$DBI::errstr";
$SQL_sth->finish || die "$DBI::errstr";
The error I get is:
DBD::ADO::st execute failed: Can't Execute Command 'insert into testtb (col1) values (4)'
  Package    : DBD::ADO::st
  Filename   : C:/Perl64/site/lib/DBD/ADO.pm
  Line       : 1244
  Last error : -2147217900
OLE exception from "Microsoft OLE DB Provider for SQL Server":
Cannot insert explicit value for identity column in table 'testtb' when
IDENTITY_INSERT is set to OFF.
Win32::OLE(0.1709) error 0x80040e14
    in METHOD/PROPERTYGET "Execute"
        Description : Cannot insert explicit value for identity column in table 'testtb' when IDENTITY_INSERT is set to
OFF.
        HelpContext :
           HelpFile :
        NativeError : 544
             Number : -2147217900
             Source : Microsoft OLE DB Provider for SQL Server
           SQLState : 42000
     at ./t3.pl line 30.
This is being run on a trial version of Windows Server 2012, Standard Edition with a trial version of SQL Server 2012. Both are fully patched. Perl is ActivePerl, version 5.16.3.1603.
Anyone any suggestions?
Thanks,
KTP

Answer 1

There's some perl data provider stuff wrapping ADO here, and it looks like it's resetting the connection, or otherwise preventing the IDENTITY INSERT setting from persisting between batches.
So best thing is to set IDENTITY INSERT in the same batch where you perform the insert.
A little background: you send commands to SQL Server in batches, and a batch contains 0 or more statements.  A batch is the basic unit of TSQL scripting. You are sending each statement in a separate batch, but that's not required. 
So instead of
$SQL_sth = $SQL_dbh->prepare("set identity_insert $tb ON") || die "$DBI::errstr";
$SQL_sth->execute() || die "$DBI::errstr";
$SQL_sth = $SQL_dbh->prepare("insert into $tb (col1) values (4)") || die "$DBI::errstr";
$SQL_sth->execute() || die "$DBI::errstr";
Try something like
$SQL_sth = $SQL_dbh->prepare("set identity_insert $tb ON; insert into $tb (col1) values (4)") || die "$DBI::errstr";
$SQL_sth->execute() || die "$DBI::errstr";
David
David http://blogs.msdn.com/b/dbrowne/