Bulk Parameterized Inserts

Question

I\'m trying to switch some hard-coded queries to use parameterized inputs, but I\'ve run into a problem: How do you format the input for parameterized bulk inserts?

Answer 1

Why not just use "prepare once, execute multiple" method. I know you want it to either all fail or all work, but it's not exactly hard to handle that with transactions:

http://www.php.net/manual/en/pdo.begintransaction.php

http://www.php.net/manual/en/pdo.commit.php

http://www.php.net/manual/en/pdo.rollback.php

Answer 2

Well, you have three options.

1. Build once - execute multiple. Basically, you prepare the insert once for one row, then loop over the rows executing it. Since the SQLSERVER extension doesn't support re-binding of a query after it's been prepared (you need to do dirty hacks with references) that may not be the best option.

2. Build once - execute once. Basically, you build one giant insert as you said in your example, bind it once, and execute it. This is a little bit dirty and misses some of the benefits that prepared queries gives. However, due to the requirement of references from Option 1, I'd do this one. I think it's cleaner to build a giant query rather than depend on variable references.

3. Build multiple - execute multiple. Basically, take the method you're doing, and tweak it to re-prepare the query every so many records. This prevents overly big queries and "batches" the queries. So something like this:

   $sql = 'INSERT INTO my_table (field1, field2, field3) VALUES ';
   $parameters = array();
   $data = array();
   
   $execute = function($params, $data) use ($my_connection, $sql) {
       $query = $sql . implode(', ', $parameters);
       $stmt = sqlsrv_prepare($my_connection, $query, $data);
       sqlsrv_execute($stmt);
   }
   
   while ($my_condition) {
       $parameters[] = '(?, ?, ?)';
       $data[] = value1;
       $data[] = value2;
       $data[] = value3;
       if (count($parameters) % 25 == 0) {
           //Flush every 25 records
           $execute($parameters, $data);
           $parameters = array();
           $data = array();
       }
   }
   if (!empty($parameters))  {
       $execute($sql, $parameters, $data);
   }
   

Either method will suffice. Do what you think fits your requirements best...