How to perform multiple MySQL inserts in PHP - 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

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 3

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 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.