PDO Prepared Inserts multiple rows in single query

Question

I am currently using this type of SQL on MySQL to insert multiple rows of values in one single query:

INSERT INTO `tbl` (`key1`,`key2`) VALUES (\'r1v1\',\'r1         


        

Answer 1

The Accepted Answer by Herbert Balagtas works well when the $data array is small. With larger $data arrays the array_merge function becomes prohibitively slow. My test file to create the $data array has 28 cols and is about 80,000 lines. The final script took 41s to complete.

Using array_push() to create $insert_values instead of array_merge() resulted in a 100X speed up with execution time of 0.41s.

The problematic array_merge():

$insert_values = array();

foreach($data as $d){
 $question_marks[] = '('  . placeholders('?', sizeof($d)) . ')';
 $insert_values = array_merge($insert_values, array_values($d));
}

To eliminate the need for array_merge(), you can build the following two arrays instead:

//Note that these fields are empty, but the field count should match the fields in $datafields.
$data[] = array('','','','',... n ); 

//getting rid of array_merge()
array_push($insert_values, $value1, $value2, $value3 ... n ); 

These arrays can then be used as follows:

function placeholders($text, $count=0, $separator=","){
    $result = array();
    if($count > 0){
        for($x=0; $x<$count; $x++){
            $result[] = $text;
        }
    }

    return implode($separator, $result);
}

$pdo->beginTransaction();

foreach($data as $d){
 $question_marks[] = '('  . placeholders('?', sizeof($d)) . ')';
}

$sql = "INSERT INTO table (" . implode(",", array_keys($datafield) ) . ") VALUES " . implode(',', $question_marks);

$stmt = $pdo->prepare ($sql);
try {
    $stmt->execute($insert_values);
} catch (PDOException $e){
    echo $e->getMessage();
}
$pdo->commit();