How to perform multiple MySQL inserts in PHP

Question

I need to insert many rows ( between 150 to 300 ) into MySQL table and I want to know the better of the following approaches in terms of performance:

Approach 1 :

foreach( $persons as $person ){

       $stmt = $dbLink->prepare( "INSERT INTO table SET id = :ID, 
                                                 name = :name, 
                                                 email = :email, 
                                                 mobile = :mobile");
       $stmt->execute( array( ':ID'=>$person->getID(),
                              ':name'=>$person->getName(),
                              ':email'=>$person->getEmail(),
                              ':mobile'=>$person->getMobile(),
                              ) );
}

Approach 2:

$stmt = $dbLink->prepare( "INSERT INTO table SET id = :ID, 
                                                 name = :name, 
                                                 email = :email, 
                                                 mobile = :mobile");

$stmt->bindParam( ':ID', $person->getID(), PDO::PARAM_STR );
$stmt->bindParam( ':name', $person->getName(), PDO::PARAM_STR );
$stmt->bindParam( ':email', $person->getEmail(), PDO::PARAM_STR );
$stmt->bindParam( ':mobile', $person->getMobile(), PDO::PARAM_STR );

foreach( $persons as $person ){

       $stmt->execute(); 
}

Answer 1

It is the amount of calls to the database what makes the difference. Reduce the amount of calls as much as possible.

Instead of this:

insert (a,b,c) values (d,e,f); 
insert (a,b,c) values (g,h,i); 
insert (a,b,c) values (j,k,l); 
insert (a,b,c) values (m,n,o);

do this:

insert (a,b,c) values (d,e,f),(g,h,i),(j,k,l),(m,n,o);

Thus making in one call what you would do in 4 calls.

Answer 2

To answer to your question, this is the way you should structure your prepare / bind / execute phases:

//prepare the query only the first time
$stmt = $dbLink->prepare( "INSERT table (id, name, email, mobile) 
                           VALUES (:ID, :name, :email, :mobile)" ); 


//bind params and execute for every person   
foreach( $persons as $person ){
    $stmt->bindValue( ':ID', $person->getID(), PDO::PARAM_STR );
    $stmt->bindValue( ':name', $person->getName(), PDO::PARAM_STR );
    $stmt->bindValue( ':email', $person->getEmail(), PDO::PARAM_STR );
    $stmt->bindValue( ':mobile', $person->getMobile(), PDO::PARAM_STR );

    $stmt->execute(); 
}

If you have PDO::ATTR_EMULATE_PREPARES = false, the query will be prepared by mysql only the first time.

In the first case it would be re-prepared for every loop cycle

As correctly other users are saying, remember that a better performance improvement would be to make ONLY one insert instead of many insert in a for loop

---

EDIT: How to use parameter bindings AND one query

To use parameters' binding and only one query a solution could be:

$placeholders = "";    //this will be filled with placeholders : ( :id_1, :name_1, :email_1, :mobile_1),( :id_2 ... )
$parameters = array(); //this will keep the parameters bindings

$i = 1;
foreach( $persons as $person )
{
    //add comma if not first iteration
    if ( $placeholders )
        $placeholders .= ", ";

    //build the placeholders string for this person
    $placeholders .= "( :id_$i, :name_$i, :email_$i, :mobile_$i )";

    //add parameters for this person
    $parameters[":id_$i"] = $person->getID(); 
    $parameters[":name_$i"] = $person->getName(); 
    $parameters[":email_$i"] = $person->getEmail(); 
    $parameters[":mobile_$i"] = $person->getMobile(); 

    $i++;
}

//build the query
$stmt = $dbLink->prepare( "INSERT INTO table (id, name, email, mobile) 
                           VALUES " . $placeholders );

//execute the query passing parameters
$stmt->execute( $parameters );

In the first part of the loop we build the string $placeholders with a set of placeholders for every person, in the second part of the loop we store the bindings of the values of the placeholders in the $parameters array

At the end of the loop we should have all the placeholders and parameters set, and we can execute the query passing the $parameters array to the execute method. This is an alternative way in respect to use the bindValue / bindParam methods but the result should be the same

I think this is the only way to use parameter bindings AND use only one query

Answer 3

You can use the below code to avoid multiple SQL calls and insert the data in Single SQL call

$first_string = "INSERT INTO table (id, name, email,mobile) VALUES ";//Basic query
foreach( $persons as $person )
{
    $first_string .="(".$person->getID().",".$person->getName().",".$person->getEmail().",".$person->getMobile()."),";//Prepare the values
}

$final_query_string = substr($first_string, 0,-1);// This will remove the extra , at the end of the string

$stmt = $dbLink->prepare($final_query_string);
$stmt->execute(); 

Now execute the final query string prepared.

This way the query is prepared as the string and you need to execute it in one go. This will make a single SQL call

Answer 4

//declare array of values to be passed into PDO::Statemenet::execute()
$values = array();

//prepare sql string
$sql = 'INSERT INTO students ( id, name, email, mobile ) VALUES ';

 foreach( $students as $student ){

      $sql .= '( ?, ?, ?, ? ),';  //concatenate placeholders with sql string  

      //generate array of values and merge with previous values 
      $values = array_merge( $values,  array(  $student->getID(), 
                                               $student->getName(),
                                               $student->getEmail(),                       
                                               $student->getMobile(),
                                            )
                           );
 }

 $sql = rtrim( $sql, ',' );   //remove the trailing comma (,) and replace the sql string
 $stmt = $this->dbLink->prepare( $sql );            
 $stmt->execute( $values );

Full credits to all who have inspired me to arrive at this solution. This seems to be terse and clear:

In particular, the answer of JM4 at PDO Prepared Inserts multiple rows in single query really helped. I also recognise Moppo on this page.