Mysql INSERT and DELETE in a single statement with dependant on eachother - php

Question

I have the following two queries. Second query is dependent on first one.
$query1 = mysql_query("Insert into table_one set ---- ");
if($query1)
{
$query2 = mysql_query("delete from table_two where condition---");
if($query2)
{
$message = "both queries executed successfully";
}
else
{
$del = mysql_query("delete record inserted by $query1");
}
}
Can we execute these two queries in a single statement so that both queries depend on each other.If INSERT query fail, DELETE query also fail it's execution as well as if DELETE query fail INSERTION in query first fail.
Thanks

Answer 1

If I good understand what you need, simply use transactions.
Run this query before your insertion:
mysql_query('begin');
And then, if everything went fine, commit the transaction:
mysql_query('commit');
In case of any failures, you may rollback every change you made:
mysql_query('rollback');
Note that in case of MySQL, the MyISAM engine does not support rollback in transactions, so use InnoDB.
Read more about transactions here: https://dev.mysql.com/doc/refman/5.0/en/commit.html
Example with your code:
<?PHP
mysql_query('begin'); //start transaction
$query1 = mysql_query("Insert into table_one set ---- ");
if($query1)
{
$query2 = mysql_query("delete from table_two where condition---");
if($query2)
{
mysql_query('commit'); //both queries went fine, so let's save your changes and end the transaction
$message = "both queries executed successfully";
}
else
{
mysql_query('rollback'); //query2 failed, so let's rollback changes made by query1 and end the transaction
}
}
else
mysql_query('rollback'); //query1 failed, so let's end the transaction

Answer 2

If query2 fails it doesn't check query1.
$query1 = mysql_query("Insert into table_one set ---- ");
$query2 = mysql_query("delete from table_two where condition---");
if( $query2 && $query1)
{
$message = "both queries executed successfully";
}
else if(!$query2)
{
$del = mysql_query("delete record inserted by $query1");
}

Answer 3

You can use transaction, if any query fails then call rollback, otherwise commit

Answer 4

I found a best solution.
Extending idea of #Luki i wrote the following code and it give me too much satisfied answer. First use the following function.
function multi_statement()
{
global $conn;
$total_args = func_get_args();
$args = implode($total_args,";");
$args = "begin;".$args.";commit;";
$number = 0;
if($conn->multi_query($args))
{
do
{
if ($conn->more_results())
{
$number++;
}
}
while($conn->next_result());
}
if($number < (count($total_args)+1))
{
$conn->query('rollback');
echo "Sorry..!!! Error found in Query no:".$number;
}
else
{
echo "All queries executed successfully";
}
}
Then I called the function with number of statements, all these statements are dependent on each other. In-case there is error in any query, no one query occur any changes in database.
$statement1 = "INSERT INTO `pic_gall`.`admin` (`admin_id`, `username`, `password`) VALUES (NULL, 'as1', 'as1')";
$statement2 = "INSERT INTO `pic_gall`.`admin` (`admin_id`, `username`, `password`) VALUES (NULL, 'as2', 'as2')";
$statement3 = "INSERT INTO `pic_gall`.`admin` (`admin_id`, `username`, `password`) VALUES (NULL, 'as3', 'as3')";
$statement4 = "INSERT INTO `pic_gall`.`admin` (`admin_id`, `username`, `password`) VALUES (NULL, 'as4', 'as4')";
$statement5 = "DELETE from user where user_id = '12'";
multi_statement($statement1,$statement2,$statement3,$statement4,$statement5);