use DBI;
my $jobID = 1;
$dbh = DBI->connect("dbi:mysql:$database:$db_server", $user, $password) or die "Connection ERROR!";
$dbh->do('USE MultiRunScheduler');
$dbh->do('UPDATE Scheduler SET RequestStatus="CANCELED" WHERE ID="$jobID";')
print "Scheduled Jobs deleted";
I'm trying to change the RequestStatus field of a database based on ID but it's not working through the UPDATE statement. It prints out Scheduled Jobs deleted and the entire program runs successfully but it doesn't update the database RequestStatus field. If I remove ID="$jobID" and change it to ID=1 then the RequestStatus entry in the database changes.
Any idea how to get around this?
Perl does not expand variables inside single-quoted strings.
http://perldoc.perl.org/perldata.html#Scalar-value-constructors says in part:
String literals are usually delimited by either single or double quotes. They work much like quotes in the standard Unix shells: double-quoted string literals are subject to backslash and variable substitution; single-quoted strings are not (except for \' and \ ).
Also you should use single-quotes for string delimiters inside your SQL.
So this:
$dbh->do('UPDATE Scheduler SET RequestStatus="CANCELED" WHERE ID="$jobID";')
Should be this:
$dbh->do("UPDATE Scheduler SET RequestStatus='CANCELED' WHERE ID='$jobID'");
If you want to really use best practices, use bind parameters in your SQL instead of putting variables inside strings. Then you don't need to worry about what kind of quotes you use. Even if the parameter is a string type, you don't put the parameter placeholder in quotes in SQL.
Example:
$dbh->do("UPDATE Scheduler SET RequestStatus='CANCELED' WHERE ID=?", undef, $jobID);
Related
The MySQL documentation says that it should be \'. However, both scite and mysql shows that '' works. I saw that and it works. What should I do?
The MySQL documentation you cite actually says a little bit more than you mention. It also says,
A “'” inside a string quoted with “'” may be written as “''”.
(Also, you linked to the MySQL 5.0 version of Table 8.1. Special Character Escape Sequences, and the current version is 5.6 — but the current Table 8.1. Special Character Escape Sequences looks pretty similar.)
I think the Postgres note on the backslash_quote (string) parameter is informative:
This controls whether a quote mark can be represented by \' in a string literal. The preferred, SQL-standard way to represent a quote mark is by doubling it ('') but PostgreSQL has historically also accepted \'. However, use of \' creates security risks...
That says to me that using a doubled single-quote character is a better overall and long-term choice than using a backslash to escape the single-quote.
Now if you also want to add choice of language, choice of SQL database and its non-standard quirks, and choice of query framework to the equation, then you might end up with a different choice. You don't give much information about your constraints.
Standard SQL uses doubled-up quotes; MySQL has to accept that to be reasonably compliant.
'He said, "Don''t!"'
What I believe user2087510 meant was:
name = 'something'
name = name.replace("'", "\\'")
I have also used this with success.
There are three ways I am aware of. The first not being the prettiest and the second being the common way in most programming languages:
Use another single quote: 'I mustn''t sin!'
Use the escape character \ before the single quote': 'I mustn\'t sin!'
Use double quotes to enclose string instead of single quotes: "I mustn't sin!"
just write '' in place of ' i mean two times '
Here's an example:
SELECT * FROM pubs WHERE name LIKE "%John's%"
Just use double quotes to enclose the single quote.
If you insist in using single quotes (and the need to escape the character):
SELECT * FROM pubs WHERE name LIKE '%John\'s%'
Possibly off-topic, but maybe you came here looking for a way to sanitise text input from an HTML form, so that when a user inputs the apostrophe character, it doesn't throw an error when you try to write the text to an SQL-based table in a DB. There are a couple of ways to do this, and you might want to read about SQL injection too.
Here's an example of using prepared statements and bound parameters in PHP:
$input_str = "Here's a string with some apostrophes (')";
// sanitise it before writing to the DB (assumes PDO)
$sql = "INSERT INTO `table` (`note`) VALUES (:note)";
try {
$stmt = $dbh->prepare($sql);
$stmt->bindParam(':note', $input_str, PDO::PARAM_STR);
$stmt->execute();
} catch (PDOException $e) {
return $dbh->errorInfo();
}
return "success";
In the special case where you may want to store your apostrophes using their HTML entity references, PHP has the htmlspecialchars() function which will convert them to '. As the comments indicate, this should not be used as a substitute for proper sanitisation, as per the example given.
Replace the string
value = value.replace(/'/g, "\\'");
where value is your string which is going to store in your Database.
Further,
NPM package for this, you can have look into it
https://www.npmjs.com/package/mysql-apostrophe
I think if you have any data point with apostrophe you can add one apostrophe before the apostrophe
eg. 'This is John's place'
Here MYSQL assumes two sentence 'This is John' 's place'
You can put 'This is John''s place'. I think it should work that way.
In PHP I like using mysqli_real_escape_string() which escapes special characters in a string for use in an SQL statement.
see https://www.php.net/manual/en/mysqli.real-escape-string.php
I'm attempting to get an entry into a database with a single quote in the string. My problem is that it is going into the database with the escape included in the string.
when I run:
$var = "'12 Toyota 4Runner";
$sql=$pdo->prepare("UPDATE $tbl_name SET description=:var WHERE id=:id");
$sql->execute(array(':id' => $id, ':var' => $var));
In my database, the entry will be "\'12 Toyota 4Runner"
Is there a way to remove the '\'?
Yes.
However, PDO has nothing to do with this quote - some other code is adding it.
Either get rid of magic quotes
And take out all the escaping functions from your code, especially from that "all protection function" loved by all the new users.
The MySQL documentation says that it should be \'. However, both scite and mysql shows that '' works. I saw that and it works. What should I do?
The MySQL documentation you cite actually says a little bit more than you mention. It also says,
A “'” inside a string quoted with “'” may be written as “''”.
(Also, you linked to the MySQL 5.0 version of Table 8.1. Special Character Escape Sequences, and the current version is 5.6 — but the current Table 8.1. Special Character Escape Sequences looks pretty similar.)
I think the Postgres note on the backslash_quote (string) parameter is informative:
This controls whether a quote mark can be represented by \' in a string literal. The preferred, SQL-standard way to represent a quote mark is by doubling it ('') but PostgreSQL has historically also accepted \'. However, use of \' creates security risks...
That says to me that using a doubled single-quote character is a better overall and long-term choice than using a backslash to escape the single-quote.
Now if you also want to add choice of language, choice of SQL database and its non-standard quirks, and choice of query framework to the equation, then you might end up with a different choice. You don't give much information about your constraints.
Standard SQL uses doubled-up quotes; MySQL has to accept that to be reasonably compliant.
'He said, "Don''t!"'
What I believe user2087510 meant was:
name = 'something'
name = name.replace("'", "\\'")
I have also used this with success.
There are three ways I am aware of. The first not being the prettiest and the second being the common way in most programming languages:
Use another single quote: 'I mustn''t sin!'
Use the escape character \ before the single quote': 'I mustn\'t sin!'
Use double quotes to enclose string instead of single quotes: "I mustn't sin!"
just write '' in place of ' i mean two times '
Here's an example:
SELECT * FROM pubs WHERE name LIKE "%John's%"
Just use double quotes to enclose the single quote.
If you insist in using single quotes (and the need to escape the character):
SELECT * FROM pubs WHERE name LIKE '%John\'s%'
Possibly off-topic, but maybe you came here looking for a way to sanitise text input from an HTML form, so that when a user inputs the apostrophe character, it doesn't throw an error when you try to write the text to an SQL-based table in a DB. There are a couple of ways to do this, and you might want to read about SQL injection too.
Here's an example of using prepared statements and bound parameters in PHP:
$input_str = "Here's a string with some apostrophes (')";
// sanitise it before writing to the DB (assumes PDO)
$sql = "INSERT INTO `table` (`note`) VALUES (:note)";
try {
$stmt = $dbh->prepare($sql);
$stmt->bindParam(':note', $input_str, PDO::PARAM_STR);
$stmt->execute();
} catch (PDOException $e) {
return $dbh->errorInfo();
}
return "success";
In the special case where you may want to store your apostrophes using their HTML entity references, PHP has the htmlspecialchars() function which will convert them to '. As the comments indicate, this should not be used as a substitute for proper sanitisation, as per the example given.
Replace the string
value = value.replace(/'/g, "\\'");
where value is your string which is going to store in your Database.
Further,
NPM package for this, you can have look into it
https://www.npmjs.com/package/mysql-apostrophe
I think if you have any data point with apostrophe you can add one apostrophe before the apostrophe
eg. 'This is John's place'
Here MYSQL assumes two sentence 'This is John' 's place'
You can put 'This is John''s place'. I think it should work that way.
In PHP I like using mysqli_real_escape_string() which escapes special characters in a string for use in an SQL statement.
see https://www.php.net/manual/en/mysqli.real-escape-string.php
I am going to write a bash script to manipulate user's data on mysql DB.
Here is the problem. I need to pass a variable's value into a Mysql query string:
read USERNAME;
echo "USE drupdb; SELECT uid FROM users WHERE name= '%USERNAME';" > /tmp/query.sql ;
Whatever combinations that I've used (including backslashs befor single-quotes to scape them) did not do the trick. I still get something other than the value of %USERNAME inside the query.sql.
I appreciate your hints.
You need to use $ to dereference a variable. Change %USERNAME to $USERNAME and everything should work fine:
read USERNAME;
echo "USE drupdb; SELECT uid FROM users WHERE name= '$USERNAME';"
I am using MySQL with MATLAB, and I want to get a name from user, and pass it to the table in mySQL, but it is rejecting a variable name in place of string
var_name=input('enter the name:');
mysql('insert into table (name) values (var_name)');
Any suggestions?
FIRST read the comments to this question - you don't want to shoot yourself in the foot with a mysql injection security problem. You have been warned. Now, to solve your current problem, without addressing the security risk of the whole approach when it comes to building SQL queries, read on...
In principle Amro has already posted two solutions for you which work, but since you have not accepted it I'll explain further.
Your problem is that you are not telling MATLAB which parts of your query it should interpret as a literal string, and which parts it should interpret as a variable name. To solve this, you can just end the literal string where appropriate, i.e. after the opening brackets, and then start them again before the closing brackets.
In between those literal strings you want to add the contents of your variables, so you need to tell MATLAB to concat your literal strings with your variables, since the mysql command probably expects the whole query as a single string. So in essence you want to take the string 'insert into table(' and the string saved in the variable name and the string ') values (' and so on and glue them into one big string. Amro and Isaac have shown you two solutions of how to do this without much explanation:
horzcat('insert into table (', name, ') values (', var_name, ')')
uses the function horzcat, while
['insert into table (' name ') values (' var_name ')']
uses the fact that MATLAB treats strings as arrays of characters so that you can just use square brackets to form a large array containing the strings one after the other.
The third solution, offered by Amro, is a bit more sublte:
sprintf('insert into table (%s) values (%s)',name,var_name)
It tells the function sprintf (which is made for that purpose) "take the string which I supply as first parameter and replace occurences of %s with the strings I supply as the following parameters. This last technique is in particular useful if you also need to insert numbers into your string, because sprintf can also convert numbers to string and allows fine control over how they are formatted. You should have a close look at the help page for sprintf to know more :-).
Try this instead:
mysql(['insert into table (' name ') values (' var_name ')']);
or even:
mysql(sprintf('insert into table (%s) values (%s)',name,var_name));
I believe the problem you are having is the same as the one in this other question. It sounds like you want to create a command string that itself contains a ' delimited string, which would require you to escape each ' with another ' when you create your command string (note the first example in this string handling documentation). Note also you may want to use the 's' option for the INPUT function:
var_name = input('Enter the name: ','s'); %# Treats input like a string
commandString = sprintf('insert into table (name) values (''%s'')', var_name);
%# Note the two apostrophes --^
mysql(commandString);
If I were to enter Ken for the input, the string commandString would contain the following:
insert into table (name) values ('Ken')
And of course, as others have already mentioned, beware injection vulnerabilities.