For tables that have no primary keys (don't blame me, I didn't write the horrifying SQL schema ;)), warnings will be thrown because array_key_exists is invoked against an undefined variable.

At/around line 225 in Zend/Db/Adapter/Pdo/Mssql.php is the offending bit of code:

$isPrimary = array_key_exists($row[$column_name], $primaryKeyColumn);

$primaryKeyColumn is never initialised, so somewhere around line 209 this change should be made:

$primaryKeysResult = $stmt->fetchAll(Zend_Db::FETCH_NUM);
        $pkey_column_name = 3;
        $pkey_key_seq = 4;
+        
+        $primaryKeyColumn = array();
        foreach ($primaryKeysResult as $pkeysRow) {
            $primaryKeyColumn[$pkeysRow[$pkey_column_name]] = $pkeysRow[$pkey_key_seq];
        }

Initially I thought it should be enough to just cast to an array, but that still threw a Notice. This actually addresses the issue.

Cheers,