How to insert multiple rows from array using CodeIgniter framework?

Assembling one INSERT statement with multiple rows is much faster in MySQL than one INSERT statement per row.

That said, it sounds like you might be running into string-handling problems in PHP, which is really an algorithm problem, not a language one. Basically, when working with large strings, you want to minimize unnecessary copying. Primarily, this means you want to avoid concatenation. The fastest and most memory efficient way to build a large string, such as for inserting hundreds of rows at one, is to take advantage of the implode() function and array assignment.

$sql = array(); 
foreach( $data as $row ) {
    $sql[] = '("'.mysql_real_escape_string($row['text']).'", '.$row['category_id'].')';
}
mysql_query('INSERT INTO table (text, category) VALUES '.implode(',', $sql));

The advantage of this approach is that you don't copy and re-copy the SQL statement you've so far assembled with each concatenation; instead, PHP does this once in the implode() statement. This is a big win.

If you have lots of columns to put together, and one or more are very long, you could also build an inner loop to do the same thing and use implode() to assign the values clause to the outer array.

mysqli in PHP 5 is an object with some good functions that will allow you to speed up the insertion time for the answer above:

$mysqli->autocommit(FALSE);
$mysqli->multi_query($sqlCombined);
$mysqli->autocommit(TRUE);

Turning off autocommit when inserting many rows greatly speeds up insertion, so turn it off, then execute as mentioned above, or just make a string (sqlCombined) which is many insert statements separated by semi-colons and multi-query will handle them fine.

You could prepare the query for inserting one row using the mysqli_stmt class, and then iterate over the array of data. Something like:

$stmt =  $db->stmt_init();
$stmt->prepare("INSERT INTO mytbl (fld1, fld2, fld3, fld4) VALUES(?, ?, ?, ?)");
foreach($myarray as $row)
{
    $stmt->bind_param('idsb', $row['fld1'], $row['fld2'], $row['fld3'], $row['fld4']);
    $stmt->execute();
}
$stmt->close();

Where 'idsb' are the types of the data you're binding (int, double, string, blob).

Multiple insert/ batch insert is now supported by CodeIgniter.

$data = array(
   array(
      'title' => 'My title' ,
      'name' => 'My Name' ,
      'date' => 'My date'
   ),
   array(
      'title' => 'Another title' ,
      'name' => 'Another Name' ,
      'date' => 'Another date'
   )
);

$this->db->insert_batch('mytable', $data);

// Produces: INSERT INTO mytable (title, name, date) VALUES ('My title', 'My name', 'My date'), ('Another title', 'Another name', 'Another date')