使用PHP-PDO记录查询时如何获取最后的插入ID

Question

Recently I have been creating a function to record every changes in the database, simply I record it to a table.

Table backup_log: backupTableName, backupLastUpdate, backupLastupload

So, every time changed, its will record the date to "backup_log". It's runs well, but I have problem when I need Last Insert Id, I using $orderid = $dbh->lastInsertId('orderId'); to get "last insert Id", but its return "0". I figure out that the problem comes when I put querylog() function that runs another query while the query() function still also run. coz its using same PDO object. So, any suggestion for me to able to get "last insert id", while runs querylog() ?

This is my code:

//$dbh is object of PDO connection

$sql = query("INSER INTO orders ...");
$orderid = $dbh->lastInsertId('orderId'); // table "orders"

function query($sql){
    #this function is not the full version, just for example
    global $dbh;
    $query=$dbh->exec($sql);

    querylog($sql); // Log every insert, delete and update query
}   

function querylog($sql){  
    global $dbh; // PDO object
    global $now;

    //Table backup_log: backupTable, backupLastUpdate, backupLastupload

    ###### Log: for insert and update ########
    #if the query too long, cut for 200 chars and convert them to array
    $sql_clean_space=str_replace(array("  ",'`'),array(" ",''),$sql); //change double space to single space
    if(strlen($sql_clean_space) > 200){
        $sql_clean_space = substr($sql_clean_space, 0, 200); // get only 200 char
    }

    $sql_array=explode(" ", $sql_clean_space); //convert to array to get the command name, insert or update
    $now_date=$now;

    #save log
    if(strtolower($sql_array[0])=='insert' or strtolower($sql_array[0])=='delete'){
        #check whether the query is insert or update
        $sqlx = "SELECT * FROM backup_log WHERE backupTable='".$sql_array[2]."'";
        $query=$dbh->query($sqlx);  
        $check_row=$query->rowCount($query);

        if($check_row){
            $sql_log="UPDATE backup_log SET backupLastUpdate='$now' WHERE backupTable='". $sql_array[2] . "'";
        }else{
            $sql_log="INSERT INTO backup_log VALUES('".$sql_array[2]."', '$now_date','$now_date')";
        } 
    }elseif(strtolower($sql_array[0])=='update'){
        $sqlx = "SELECT * FROM backup_log WHERE backupTable='".$sql_array[1]."'";
        $query=$dbh->query($sqlx);  
        $check_row=$query->rowCount($query);

        if($check_row){ 
            $sql_log="UPDATE backup_log SET backupLastUpdate='$now' WHERE backupTable='". $sql_array[1] . "'";
            }else{
            $sql_log="INSERT INTO backup_log VALUES('".$sql_array[1]."', '$now_date','$now_date')";
        }
    }
    $query_log=$dbh->exec($sql_log);
    ####### End of log ######################
}

Answer 1

Maybe you can assign last insert id in query functions and it can be preserved while query executions. See my code below;

$sql = query("INSER INTO orders ...", 'orderId'); //$sql is equal to last insert id 
$orderid = $sql

function query($sql, $specific_id_column){
    #this function is not the full version, just for example
    global $dbh;
    $query=$dbh->exec($sql);
    $last_id = $dbh->lastInsertId($specific_id_column);
    querylog($sql); // Log every insert, delete and update query
    return $last_id;
}