Insert Batch Problems

[eluser]Unknown[/eluser]
Hello,

I'm trying to insert lots of records into the database in one go so I want to use the $this->db->insert_batch() functionality. But I get an error message

Code:

A PHP Error was encountered
Severity: Notice
Message: Array to string conversion
Filename: mysql/mysql_driver.php
Line Number: 587

Now I notice that this array works and doesn't give me an error

Code:

$data["1"] = array(
    "sku" => 934896,
    "title" => "Savannah Barstool",
    "description" => "Natural Linen",
    "price" => 475.00,
    "category" => 22
);
$data["2"] = array(
    "sku" => 583401,
    "title" => "Coffee table",
    "description" => "Steel and Reclaimed Wood",
    "price" => 475.00,
    "category" => 22,
);

but this test array does create an error. Notice the "dimensions" field. This happens if I add or remove fields from either array. Do both arrays have to have the exact same fields?

Code:

$data["1"] = array(
    "sku" => 934896,
    "title" => "Savannah Barstool",
    "description" => "Natural Linen",
    "price" => 475.00,
    "category" => 22,
    "dimensions" => "22'W x 20'D x 37'H",
);
$data["2"] = array(
    "sku" => 583401,
    "title" => "Coffee table",
    "description" => "Steel and Reclaimed Wood",
    "price" => 475.00,
    "category" => 22,
);

What is another solution?