PLEASE READ THE QUESTION CAREFULLY. It is not usual silly "my code doesn't work!!!" question.
When I run this code with intended error
try {
$sth = $dbh->prepare("SELECT id FROM users WHERE name INN(?,?) ");
$sth->execute(array("I'm","d'Artagnan"));
} catch (PDOException $e) {
echo $e->getMessage();
}
I get this error message
You have an error in your SQL syntax ... near 'INN('I\'m','d\'Artagnan')' at line 1
But I thought for years that query and data being sent to the server separately and never interfere. Thus I have some questions (though I doubt anyone got an answer...)
Where does it get such a familiar string representation - quoted and escaped? Is it being made especially to report an error or is it a part of actual query?
How does it work in real? Does it substitute a placeholder with data or not?
Is there a way to get whole query, not only little bit of it, for debugging purposes?
Update
mysqli does it as expected: it throws an error says near 'INN(?,?)'
try adding
$dbh->setAttribute( PDO::ATTR_EMULATE_PREPARES, false );
;)
I'm not sure about all the details, but I will try to answer.
The quotation happens on the database side. The database escapes and sanitizes all values (see bullet 2) it receives so that it gets interpreted correctly.
The moment the error is thrown, the database (in this case MySQL) prints out the query it tried to run. This wouldn't be so helpful if it just showed the prepared part.
No, it doesn't. At preparation time the query gets compiled on the server side. When a query is executed with values, only the values are transmitted. This is pretty much the same as calling PREPARE and EXECUTE on the database directly.
This depends on the database you're using. MySQL for example can log all queries to a log file (check my.cnf settings for that). But you can also use debugDumpParams() on PHP side.
I hope this was a bit helpful.
Related
This question already has answers here:
Getting raw SQL query string from PDO prepared statements
(16 answers)
Closed 6 years ago.
In PHP, when accessing MySQL database with PDO with parametrized query, how can you check the final query (after having replaced all tokens)?
Is there a way to check what gets really executed by the database?
So I think I'll finally answer my own question in order to have a full solution for the record. But have to thank Ben James and Kailash Badu which provided the clues for this.
Short Answer
As mentioned by Ben James: NO.
The full SQL query does not exist on the PHP side, because the query-with-tokens and the parameters are sent separately to the database.
Only on the database side the full query exists.
Even trying to create a function to replace tokens on the PHP side would not guarantee the replacement process is the same as the SQL one (tricky stuff like token-type, bindValue vs bindParam, ...)
Workaround
This is where I elaborate on Kailash Badu's answer.
By logging all SQL queries, we can see what is really run on the server.
With mySQL, this can be done by updating the my.cnf (or my.ini in my case with Wamp server), and adding a line like:
log=[REPLACE_BY_PATH]/[REPLACE_BY_FILE_NAME]
Just do not run this in production!!!
You might be able to use PDOStatement->debugDumpParams. See the PHP documentation .
Using prepared statements with parametrised values is not simply another way to dynamically create a string of SQL. You create a prepared statement at the database, and then send the parameter values alone.
So what is probably sent to the database will be a PREPARE ..., then SET ... and finally EXECUTE ....
You won't be able to get some SQL string like SELECT * FROM ..., even if it would produce equivalent results, because no such query was ever actually sent to the database.
I check Query Log to see the exact query that was executed as prepared statement.
I initially avoided turning on logging to monitor PDO because I thought that it would be a hassle but it is not hard at all. You don't need to reboot MySQL (after 5.1.9):
Execute this SQL in phpMyAdmin or any other environment where you may have high db privileges:
SET GLOBAL general_log = 'ON';
In a terminal, tail your log file. Mine was here:
>sudo tail -f /usr/local/mysql/data/myMacComputerName.log
You can search for your mysql files with this terminal command:
>ps auxww|grep [m]ysqld
I found that PDO escapes everything, so you can't write
$dynamicField = 'userName';
$sql = "SELECT * FROM `example` WHERE `:field` = :value";
$this->statement = $this->db->prepare($sql);
$this->statement->bindValue(':field', $dynamicField);
$this->statement->bindValue(':value', 'mick');
$this->statement->execute();
Because it creates:
SELECT * FROM `example` WHERE `'userName'` = 'mick' ;
Which did not create an error, just an empty result. Instead I needed to use
$sql = "SELECT * FROM `example` WHERE `$dynamicField` = :value";
to get
SELECT * FROM `example` WHERE `userName` = 'mick' ;
When you are done execute:
SET GLOBAL general_log = 'OFF';
or else your logs will get huge.
What I did to print that actual query is a bit complicated but it works :)
In method that assigns variables to my statement I have another variable that looks a bit like this:
$this->fullStmt = str_replace($column, '\'' . str_replace('\'', '\\\'', $param) . '\'', $this->fullStmt);
Where:
$column is my token
$param is the actual value being assigned to token
$this->fullStmt is my print only statement with replaced tokens
What it does is a simply replace tokens with values when the real PDO assignment happens.
I hope I did not confuse you and at least pointed you in right direction.
The easiest way it can be done is by reading mysql execution log file and you can do that in runtime.
There is a nice explanation here:
How to show the last queries executed on MySQL?
I don't believe you can, though I hope that someone will prove me wrong.
I know you can print the query and its toString method will show you the sql without the replacements. That can be handy if you're building complex query strings, but it doesn't give you the full query with values.
I think easiest way to see final query text when you use pdo is to make special error and look error message. I don't know how to do that, but when i make sql error in yii framework that use pdo i could see query text
This question already has answers here:
Getting raw SQL query string from PDO prepared statements
(16 answers)
Closed 6 years ago.
In PHP, when accessing MySQL database with PDO with parametrized query, how can you check the final query (after having replaced all tokens)?
Is there a way to check what gets really executed by the database?
So I think I'll finally answer my own question in order to have a full solution for the record. But have to thank Ben James and Kailash Badu which provided the clues for this.
Short Answer
As mentioned by Ben James: NO.
The full SQL query does not exist on the PHP side, because the query-with-tokens and the parameters are sent separately to the database.
Only on the database side the full query exists.
Even trying to create a function to replace tokens on the PHP side would not guarantee the replacement process is the same as the SQL one (tricky stuff like token-type, bindValue vs bindParam, ...)
Workaround
This is where I elaborate on Kailash Badu's answer.
By logging all SQL queries, we can see what is really run on the server.
With mySQL, this can be done by updating the my.cnf (or my.ini in my case with Wamp server), and adding a line like:
log=[REPLACE_BY_PATH]/[REPLACE_BY_FILE_NAME]
Just do not run this in production!!!
You might be able to use PDOStatement->debugDumpParams. See the PHP documentation .
Using prepared statements with parametrised values is not simply another way to dynamically create a string of SQL. You create a prepared statement at the database, and then send the parameter values alone.
So what is probably sent to the database will be a PREPARE ..., then SET ... and finally EXECUTE ....
You won't be able to get some SQL string like SELECT * FROM ..., even if it would produce equivalent results, because no such query was ever actually sent to the database.
I check Query Log to see the exact query that was executed as prepared statement.
I initially avoided turning on logging to monitor PDO because I thought that it would be a hassle but it is not hard at all. You don't need to reboot MySQL (after 5.1.9):
Execute this SQL in phpMyAdmin or any other environment where you may have high db privileges:
SET GLOBAL general_log = 'ON';
In a terminal, tail your log file. Mine was here:
>sudo tail -f /usr/local/mysql/data/myMacComputerName.log
You can search for your mysql files with this terminal command:
>ps auxww|grep [m]ysqld
I found that PDO escapes everything, so you can't write
$dynamicField = 'userName';
$sql = "SELECT * FROM `example` WHERE `:field` = :value";
$this->statement = $this->db->prepare($sql);
$this->statement->bindValue(':field', $dynamicField);
$this->statement->bindValue(':value', 'mick');
$this->statement->execute();
Because it creates:
SELECT * FROM `example` WHERE `'userName'` = 'mick' ;
Which did not create an error, just an empty result. Instead I needed to use
$sql = "SELECT * FROM `example` WHERE `$dynamicField` = :value";
to get
SELECT * FROM `example` WHERE `userName` = 'mick' ;
When you are done execute:
SET GLOBAL general_log = 'OFF';
or else your logs will get huge.
What I did to print that actual query is a bit complicated but it works :)
In method that assigns variables to my statement I have another variable that looks a bit like this:
$this->fullStmt = str_replace($column, '\'' . str_replace('\'', '\\\'', $param) . '\'', $this->fullStmt);
Where:
$column is my token
$param is the actual value being assigned to token
$this->fullStmt is my print only statement with replaced tokens
What it does is a simply replace tokens with values when the real PDO assignment happens.
I hope I did not confuse you and at least pointed you in right direction.
The easiest way it can be done is by reading mysql execution log file and you can do that in runtime.
There is a nice explanation here:
How to show the last queries executed on MySQL?
I don't believe you can, though I hope that someone will prove me wrong.
I know you can print the query and its toString method will show you the sql without the replacements. That can be handy if you're building complex query strings, but it doesn't give you the full query with values.
I think easiest way to see final query text when you use pdo is to make special error and look error message. I don't know how to do that, but when i make sql error in yii framework that use pdo i could see query text
Hopefully someone will be able to help me because I've been banging my head against the wall all night trying to solve this little problem.
I want to insert data into a database using PDO (which I am admittedly not the most knowledgeable about). I am using a statement that I have used many times in the past, but for some reason this time it's not working. The statement is as follows:
$userID = "Johnny5";
$sql = "INSERT INTO user_info(user_id) VALUES(:user-id)";
if($stmt = $this->_db->prepare($sql))
{
$stmt->bindParam(":user-id", $userID, PDO::PARAM_STR);
$stmt->execute();
$stmt->closeCursor();
return TRUE;
} else {
return FALSE;
}
But unfortunately this is always returning TRUE without ever entering anything into my database. I have tried every combination changes to the statement that I could think of, but I am still at a loss.
I hope someone out there can point out a really simple error that I have made.
Also, placing single quote marks around the parameter :user-id in the $sql string is the only way that I can get anything to appear into the database, but that obviously doesn't enter in any actual data into the database.
EDIT
I have also changed the PDO parameter types from PDO::PARAM_STR to PDO::PARAM_INT but have still had no luck.
After further investigation, execute() is returning FALSE.
Solution
Thanks to everyone for their guidance. #Nabeel was correct in saying not to use placeholders in PDO parameters.
Don't use dashes in your SQL statements.
Make this:
:user-id
as this:
:userid
$userId is a string in this code, yet you say it's in int by defining PDO::PARAM_INT. Try replacing it with PDO::PARAM_STRING or try setting $userId to a number(1 for example)
If something fails, then there most certainly was an error. First you need to find out which statement fails by checking their return values (always read about every command you use in the PHP Manual first).
If you've located which command failed, use PDOStatement->errorInfo to find out more about the concrete error.
That information should help you to solve your issue.
Update: And if you want to deal with Exceptions (as Pekka suggested): How to squeeze error message out of PDO?
I have a complex query that gets executed like this:
if ($stmt = $dbi->prepare($pt_query)) {
$stmt->bind_param('ssssssssi', $snome,$scognome,$ssocieta,$svia,$slocalita,$sprovincia,$scap,$stelefono,$sfax,$uid);
$stmt->execute();
echo $dbi->error;
$stmt->close();
} else {
printf("Error -> %s\n", $dbi->error);
}
This thing is failing without any error, it simply doesn't update the database. Since there is a ton of data that gets treated before this thing I would like to know if there is any way to show the actual query that mysqli is executing in order to understand where the problem is.
Thank you.
If your statement is failing, you should check $stmt->error (as opposed to $dbi->error). As far as getting the actual text of the query: it's not possible. When using prepared statements, the library is using a special protocol that doesn't generate an actual query string for each ->execute() call.
You could turn on logging on the MySQL DB itself, ie. add a log=logfile line to my.ini.
Refer to the MySQL documentation for more information if needed.
Based on the PHP mysql website there is no actual way of doing it. But you may try this function as it gives you errors in your query.
Here's a tool I found that may help MySQLi Prepare Statement checker
This question already has answers here:
Getting raw SQL query string from PDO prepared statements
(16 answers)
Closed 6 years ago.
In PHP, when accessing MySQL database with PDO with parametrized query, how can you check the final query (after having replaced all tokens)?
Is there a way to check what gets really executed by the database?
So I think I'll finally answer my own question in order to have a full solution for the record. But have to thank Ben James and Kailash Badu which provided the clues for this.
Short Answer
As mentioned by Ben James: NO.
The full SQL query does not exist on the PHP side, because the query-with-tokens and the parameters are sent separately to the database.
Only on the database side the full query exists.
Even trying to create a function to replace tokens on the PHP side would not guarantee the replacement process is the same as the SQL one (tricky stuff like token-type, bindValue vs bindParam, ...)
Workaround
This is where I elaborate on Kailash Badu's answer.
By logging all SQL queries, we can see what is really run on the server.
With mySQL, this can be done by updating the my.cnf (or my.ini in my case with Wamp server), and adding a line like:
log=[REPLACE_BY_PATH]/[REPLACE_BY_FILE_NAME]
Just do not run this in production!!!
You might be able to use PDOStatement->debugDumpParams. See the PHP documentation .
Using prepared statements with parametrised values is not simply another way to dynamically create a string of SQL. You create a prepared statement at the database, and then send the parameter values alone.
So what is probably sent to the database will be a PREPARE ..., then SET ... and finally EXECUTE ....
You won't be able to get some SQL string like SELECT * FROM ..., even if it would produce equivalent results, because no such query was ever actually sent to the database.
I check Query Log to see the exact query that was executed as prepared statement.
I initially avoided turning on logging to monitor PDO because I thought that it would be a hassle but it is not hard at all. You don't need to reboot MySQL (after 5.1.9):
Execute this SQL in phpMyAdmin or any other environment where you may have high db privileges:
SET GLOBAL general_log = 'ON';
In a terminal, tail your log file. Mine was here:
>sudo tail -f /usr/local/mysql/data/myMacComputerName.log
You can search for your mysql files with this terminal command:
>ps auxww|grep [m]ysqld
I found that PDO escapes everything, so you can't write
$dynamicField = 'userName';
$sql = "SELECT * FROM `example` WHERE `:field` = :value";
$this->statement = $this->db->prepare($sql);
$this->statement->bindValue(':field', $dynamicField);
$this->statement->bindValue(':value', 'mick');
$this->statement->execute();
Because it creates:
SELECT * FROM `example` WHERE `'userName'` = 'mick' ;
Which did not create an error, just an empty result. Instead I needed to use
$sql = "SELECT * FROM `example` WHERE `$dynamicField` = :value";
to get
SELECT * FROM `example` WHERE `userName` = 'mick' ;
When you are done execute:
SET GLOBAL general_log = 'OFF';
or else your logs will get huge.
What I did to print that actual query is a bit complicated but it works :)
In method that assigns variables to my statement I have another variable that looks a bit like this:
$this->fullStmt = str_replace($column, '\'' . str_replace('\'', '\\\'', $param) . '\'', $this->fullStmt);
Where:
$column is my token
$param is the actual value being assigned to token
$this->fullStmt is my print only statement with replaced tokens
What it does is a simply replace tokens with values when the real PDO assignment happens.
I hope I did not confuse you and at least pointed you in right direction.
The easiest way it can be done is by reading mysql execution log file and you can do that in runtime.
There is a nice explanation here:
How to show the last queries executed on MySQL?
I don't believe you can, though I hope that someone will prove me wrong.
I know you can print the query and its toString method will show you the sql without the replacements. That can be handy if you're building complex query strings, but it doesn't give you the full query with values.
I think easiest way to see final query text when you use pdo is to make special error and look error message. I don't know how to do that, but when i make sql error in yii framework that use pdo i could see query text