Bulk Parameterized Inserts - php

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?
Currently, the code looks like this:
$data_insert = "INSERT INTO my_table (field1, field2, field3) ";
$multiple_inserts = false;
while ($my_condition)
{
if ($multiple_inserts)
{
$data_insert .= " UNION ALL ";
}
$data_insert .= " SELECT myvalue1, myvalue2, myvalue3 ";
}
$recordset = sqlsrv_query($my_connection, $data_insert);
A potential solution (modified from How to insert an array into a single MySQL Prepared statement w/ PHP and PDO) appears to be:
$sql = 'INSERT INTO my_table (field1, field2, field3) VALUES ';
$parameters = array();
$data = array();
while ($my_condition)
{
$parameters[] = '(?, ?, ?)';
$data[] = value1;
$data[] = value2;
$data[] = value3;
}
if (!empty($parameters))
{
$sql .= implode(', ', $parameters);
$stmt = sqlsrv_prepare($my_connection, $sql, $data);
sqlsrv_execute($stmt);
}
Is there a better way to accomplish a bulk insert with parameterized queries?

Answer 1

Well, you have three options.
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.
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.
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...

Answer 2

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