i have a question...
Im using pdo and beginTransaction() but i dont understand some things.
My SQL table have 3 columns : id(autoincrement), username(unique), and password
And in my code i have this:
$pdo->beginTransaction();
$prepared = $pdo->prepare("INSERT INTO (username,password) VALUES(?,?)");
$prepared->$pdo->bindParam(1,"stefan");
$prepared->bindParam(2,"111111");
$prepared->execute();
$count= $prepared->rowCount();
if($count === FALSE):
$pdo->rollback();
var_dump($prepared->errorInfo());
else:
$pdo->commit();
echo "row count: {$count}";
endif;
When i execute this code, all works fine, generates id=1, username="stefan" and password="111111".
Now, I am generating an error on purpose to test rollback() function. I tried to insert same data 4 times in a row and i got unique error in $prepared->errorInfo().Works fine too.
The problem is, when im insert a new record after those 4 errors (for example, username="luv", password="222222") this new record has been inserted, but with ID=6 and not ID=2.
That is ok? rollback() should not leave the autoincrement at the last value that was correct?
I miss something?
Thanks for help.
auto inc values get "burned" when you do rollbacks. this is normal and expected.
reference this stackoverflow entry
Related
In my test-surroundings there is a database containing some Person Information (Name, E-Mail, Adress etc.). These Informations can be inserted by anyone into the database via a form. In the background they are inserted with a parameterized INSERT into the database after submission.
What I now would like to do is to detect if some person tries to insert the same values into the database again, and if he does, not inserting the new values and instead showing an error message. (So every person name in the database is unique, there are no multiple rows linked to one name).
I had a numerous number of ideas on how to accomplish this. My first one was to use a query like REPLACE or INSERT IGNORE, but this method would not give me feedback so I can display the error message.
My second attempt was to first do a SELECT-query, checking if the row already exists, and if num_rows is greater than 0, exit with the error message (and else do the INSERT-part). For this to work I will have to use parameterized queries for the SELECT too, as I´m putting some user input into it. Figuring that parameterized queries need special functions for everything you could normally do with way less lines of code, I researched in the internet on how to get num_rows from my $statement parameterized-statement-object. This is what I had in the end:
$connection = new mysqli('x', 'x', 'x', 'x');
if (mysqli_connect_error()) {
die("Connect Error");
}
$connection->set_charset("UTF-8");
$statement = $connection->stmt_init();
$statement = $connection->prepare('SELECT Name FROM test WHERE Name LIKE ?');
flags = "s";
$statement->bind_param($flags, $_POST["person_name"]);
$statement->execute();
$statement->store_result();
$result = $statement->get_result(); //Produces error
if ($result->num_rows >= 1) {
$output = "Your already registered";
} else {
$output = "Registering you...";
}
exit($output);
After all, I can´t get why mysqli still won´t give me num_rows from my statement. Any help is appreciated, thanks in advance!
Oh, and if you guys could explain to me what I have to do to get affected_rows,that would be awesome!
EDIT: I know I could to this by using unique constraints. I also found out that I can find out if INSERT IGNORE skipped the INSERT or not. But that won´t answer my complete question: Why does the SELECT num_rows alternative not work?
ANOTHER EDIT: I changed the code snippet to what I now have. Although my mysql(i)-version seems to be 5.6.33 (I echo´d it via $connection->server_info) get_result() produces the following error message:
Fatal error: Call to undefined method mysqli_stmt::get_result() in X on line X (line of get_result)
The behaviour of mysqli_num_rows() depends on whether buffered or unbuffered result sets are being used. For unbuffered result sets, mysqli_num_rows() will not return the correct number of rows until all the rows in the result have been retrieved. Note that if the number of rows is greater than PHP_INT_MAX, the number will be returned as a string.
Also make sure that you declare ->store_result() first. Moreover the function doesn't work with LIMIT used jointly with SQL_CALC_FOUND_ROWS. If you want to obtain the total rows found you must do it manually.
EDIT:
If nothing from the suggestions does not work for you, then I would propose to rewrite your SQL query:
SELECT `Name`, (SELECT COUNT(*) FROM `Persons`) AS `num_rows` FROM `Persons` WHERE `Name` LIKE ?
This query will return the total number from your Persons table, as well as Name, if exist.
I have the following in php:
try {
// INSERT FETCHED LIST INTO ARCHIVE
$stmt1 = $sql->prepare('INSERT INTO hsarchive (LIST) VALUES (?)');
$stmt1->bind_param("s",$total);
$stmt1->execute();
$stmt2 = $sql->prepare('TRUNCATE TABLE highscore');
$stmt2->execute();
$sql->rollback();
$stmt1->close();
$stmt2->close();
} catch (Exception $e) {
echo "error";
$sql->rollback();
}
Engine is InnoDB and the connection is started like:
$sql = getSQLAccess();
$sql->autocommit(false);
$sql->begin_transaction();
with getSQLAccess returning an object of the type connection with user, pw etc. in it.
No matter how I spin this, the table is truncated and the list is inserted into the archive. I tried switching around where I close the statements, and as you can see I'm currently not even committing, as I'm trying to figure out why the rollback doesnt work.
Anyone?
EDIT: So this would be the way to go, according to best answer:
try {
// INSERT FETCHED LIST INTO ARCHIVE
$stmt = $sql->prepare('INSERT INTO hsarchive (LIST) VALUES (?)');
$stmt->bind_param("s",$total);
$stmt->execute();
$stmt->close();
$stmt = $sql->prepare('DELETE FROM highscore');
$stmt->execute();
$stmt->close();
$sql->commit();
} catch (Exception $e) {
$sql->rollback();
}
DDL in transactions
Since we've figured out that there are no FK constraints to table highscore - then your issue is caused because since MySQL 5.0.3, TRUNCATE table syntax is equivalent to deletion of all rows logically but not physically
If there are no foreign key constraints to this table (your case) which restricts from doing this, MySQL will produce TRUNCATE operation via fast scheme: it will do DROP table + CREATE table. So while logically it's same to deletion of all rows, it's not the same in terms of how operation is maintained.
Why this is the difference? Because MySQL doesn't support DDL in transactions. More precise, such operations can not be rolled back. For MySQL, DDL operations will cause immediate implicit commit. That is why you see that your TRUNCATE statement: first, is committed even if you don't commit; second, rollback has no effect on it.
Solution
If you still need to rollback your operation, then, unfortunately, you'll need to use DELETE syntax instead of TRUNCATE. Unfortunately - because, obviously, DELETE is much slower than TRUNCATE, because rows will be processed one by one.
I have got this code so insert values into a table in MySQL through PHP. I have tried all the possible Insert syntax, it does not insert the data... this are the codes that i used.
$param = "xyzxyz";
$param1 = "sdfdfg";
$sql = "INSERT INTO trail (User_Name, Quiz_ID) VALUES ('".$param."','".$param1."')";
$result = $mysql->query($sql);
if($result)
echo "successful";
else
echo mysql->error;
if(mysql->errno==0)
echo "successful"
else
echo mysql->error;
I even tried the following sql syntax
"INSERT INTO trail (User_Name, Quiz_ID) VALUES ('$param1','$param1')";
"INSERT INTO `trail` (`User_Name`, `Quiz_ID`) VALUES ('$param1','$param1')";
and i tried several other none of them inserts anything into the table. and this is the table in MySQL;
trail
User_Name varchar(35)
Quiz_ID varchar(35)
It does not insert anything nor does it display any error. And I have the correct DB connection because i am able to Select from the table. Its just the insert that is tricky.
Any help would be much appreciated.
Thanks
Just a note if someone is running on similar problems:
I had a similar issue --- Insert query working on PHPMyAdmin but not working on PHP and not issuing any errors (result was true all the time).
The reason is that I was starting a transaction but forgetting to commit it...
$mysqli->autocommit(FALSE);
$mysqli->query( "START TRANSACTION" );
Never forget this:
$mysqli->commit();
It is a silly error, I know, but I was so focused on the query mistery that I forgot the transaction statements a few lines above.
Check the mysqli::$errno first.
if(mysql->errno==0)
echo "successful"
else
echo mysql->error;
What I have done is if you don't have a debugger installed, just have it email you the query. This way you can see what the final query is and if you have access to something like phpMyAdmin try manually running the query and see what happens. Another thing, make sure that you are searching for your inserted record correctly, if you are using a search query because of the number of records make sure the WHERE condition is right, that has burned me a few times.
EDIT
Missing symbol around names maybe. I have to run all my MySQL queries like
`nameOfThing`
instead of just nameOfThing
$param = "xyzxyz";
$param1 = "sdfdfg";
$sql = "INSERT INTO `trail` (`User_Name`, `Quiz_ID`) VALUES ('".$param."','".$param1."')";
$result = $mysql->query($sql);
if($result)
echo "successful";
else
echo mysql->error;
if(mysql->errno==0)
echo "successful"
else
echo mysql->error;
FYI, you are inserting $param1 twice.
You also don't have a ';' after echo "successful".
I'd suggest you clean up the code example, and try things again, and let us know.
Things to clean up
$sql = "INSERT INTO trail (User_Name, Quiz_ID) VALUES ('$param','$param1')";
You don't need to concatenate the variables in a string concatenate, you can interpolate. However, you actually should use PDO with a prepared statement to avoid the potential for SQL injection.
Add that missing ;
put that first check of if(mysql->errno==0) in (unless you are going to switch to PDO for this stuff).
Fix mysql->error to be mysql->error()
Maybe some other things from the comments.
Well, if the following code produce no error and shows 1 affected row, most likely you are looking for the result in the wrong database.
ini_set('display_errors', 1);
error_reporting(E_ALL);
$sql = "INSERT INTO trail (User_Name, Quiz_ID) VALUES ('testing','1')";
$mysql->query($sql);
var_dump($mysql->error,$mysql->affected_rows);
My tables were InnoDB tables and when i changed my tables to MyISAM the insert worked fine. Well i have never encountered this problem before. Well that did the trick for the time being.
If i want to use InnoDB engine for transactions? How can i get php to be able to insert values in InnoDB table? Any one got any suggestion? And i am using WAMP server and the MySQL is version 5.5.24. And i did change the InnoDB conf in my.ini but that did not seem to work either?
try this
$param = "xyzxyz";
$param1 = "sdfdfg";
$sql = "INSERT INTO trail (User_Name, Quiz_ID) VALUES ('".$param."','".$param1."')"; $result = $mysql_query($sql); if($result){ echo "successful";} else { echo " not successful;}
Im getting to grips with the basics of PDO.
However Im trying to get the id of the inserted row, Im using:
$query = $system->db->prepare("INSERT INTO {$this->_table} (name,description) VALUES (:name,:description)");
$query->execute(array('name'=>$name,'description'=>$description));
The tutorials I have come across are regarding transactions, however I am not using transactions!
You're probably looking for lastInsertId. "Returns the ID of the last inserted row or sequence value".
$insertedId = $system->db->lastInsertId() ;
Pay attention when using transactions.
If you call lastInsertedId after you call commit, lastInsertedId will return 0 instead of the id.
Call lastInsertedId right after execute, but before commit.
$this->db->beginTransaction();
$this->stmt->execute();
$id = $this->db->lastInsertId();
$this->db->commit();
Well thats pretty much it.
This is my query:
$query = 'ALTER TABLE permissions ADD '.$name.' INT NOT NULL DEFAULT \'0\'';
Where $name is already checked to exist with only lower case alpha letters, and not more than 20 length. Im just starting this out with very simple names.
The next 4 lines of code after that one are:
if($stmt = $db -> prepare($query))
{
$success = $stmt -> execute();
$stmt -> close();
if(!$success)
echo 'ERROR: Unsuccessful query: ',$db->error,PHP_EOL;
}
And I get back, every time
ERROR: Unsuccessful query:
And no error message. Is there a way to get more error messages so I can see what is failing? I can add new columns through phpmyadmin, but that really doesnt help me at all.
The $db is fine, i do lots of stuff before and after this one section. It is only adding new column to the table that fails.
side question: prepare() rejected my query every time when i tried to make those 2 variables, the $name and the 0 value as ? ? prepared statement values. Thats why they are in the real query and not bound later. If i could change that too I would like that.
Try to replace;
$db->error to $stmt->error
And put this before the close().
worth checking you're not trying to use a column or table name that is 'reserved'. for example you cant have a col called 'lon' or 'host'