I'm trying to use PHP to connect to SQLite. I created a database by importing a CSV file into the tables for three tables. However, I'm unable to connect using the following code:
$dbhandle = sqlite_open('db/pokedex.db', 0666, $error);
if(!$dbhandle) die ($error);
This returns the following error:
Warning: sqlite_open() [function.sqlite-open]: file is encrypted or is not a database in /pokedex/configpokedexdb-sqlite.php on line 12
file is encrypted or is not a database
Googling told me I might have a version mismatch. Despite finding some SQLite3 mentions in my phpinfo(), I decided it might still be a problem so I tried the following suggested code:
try
{
//connect to SQLite database
$dbhandle = new PDO("sqlite:db/pokedex.db"); //sqlite:VPN0.sqlite
// echo "Handle has been created ...... <br><br>";
}
catch(PDOException $e)
{
echo $e->getMessage();
echo "<br><br>Database -- NOT -- loaded successfully .. ";
die( "<br><br>Query Closed !!! $error");
}
After which I received the following error:
Warning: sqlite_exec() expects parameter 1 to be resource, object given in /home/rawdco81/public_html/pokedex/index-sqlite.php on line 53
Before this, I tried running new PDO("sqlite:VPN0.sqlite"); which was what the site provided, but that was obviously wrong because it didn't point to my .db file at all. You'll see this piece of code in the comments beside the function call.
I'm having a hard time just connecting to the database...What is the proper way to do this?
Also, I'm running PHP Version 5.2.13.
EDITED: I pasted the wrong error message in the wrong place.
Now that I look more closely.., I think you are connecting successfully in the second code segment! You shouldn't be using sqlite_exec in tandem w/ PDO though; those are two different PHP interfaces into SQLite.
The reason the first bit of code bombed is because the legacy library doesn't support PDO v3. The second bit of code is bombing once you try to run sqlite_exec against the PDO object I presume.
I bet if you put a var_dump($dbhandle); after the try/catch you'll see you've got an initialized PDO object.
Just read up on using PDO to run queries and you should be golden!
Related
I'm trying to connect database.
Here's the details of my work:
$con=mysql_connect("localhost", "root","");
mysql_select_db("employees",$con);
if(!$con)
{
die("cant establish database connection".mysql_error());
}
else
{
echo "connection Created";
where in xamp my database,which i created in phpmyadmin in localhost xamp, is on the following directory:
C:\xampp\mysql\data
Here a folder named Employees is created then it has some files in it.
when i run php file to create connection it shows nothing on the screen according to my code it must show :
connection created
now can anyone tell me where im wrong? why its not showing any output?
If that's your whole script, you're missing a closing brace at the end }.
Turn on error display, it will be useful in the future: How do I get PHP errors to display?
Also have a read of this: Why shouldn't I use mysql_* functions in PHP?
My PHP code works well in connecting remote windows system mysql database and returns the output. But, when I'm using the same to connect remote linux system's mysql database, I got the following error:
"mysql_query() expects parameter 2 to be resource, boolean given in
C:\wamp\www\mysqldb.php on line 88"
That line 88 have the following content "$this->resultQur =
mysql_query($query, $this->connID);"
Help me to solve this.
yes. The resource is null in this case. But the same works in windows mysql connection. I got the error only in linux. Need to do any change for linux environment?
While putting "print mysql_error();" i got the following error
"A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond."
The resource you're providing comes from a mysql_connect and that did not succeed!
Put error reporting on
Build some basic error handling in your script
Do not use mysql_* but mysqli_* or even better PDO with parameter binding
Output returned string from mysql_error() after your query. In that way you will see actual error.
$this->resultQur = mysql_query($query, $this->connID);
print mysql_error();
mysql_connect returns a resource on success, but a boolean "false" on error.
Your connection attempt probably failed an so the mysql_query won't be successful.
Try something like the following to see what exactly is causing the error.
mysql_connect(..) or die(mysql_error());
Additionally, it seems that the "old" mysql-library get's deprecated in PHP and it's recommended to switch to a more modern version, eg mysqli or PDO.
1 . Firstly put ini_set(‘display_errors’,1);error_reporting(E_ALL|E_STRICT); in your code at the start of the page
2 . Put Try catch around the query and print the Exception message
try { enter code here }catch (Exception $e) {
echo 'Caught exception: ', $e->getMessage(), "\n";
}
3 . Use PDO then the mysql object for query it's a modern and better approach
Use try catch around the the query and try
I wrote a utility for updating the DB from a list of numbered .sql update files. The utility stores inside the DB the index of the lastAppliedUpdate. When run, it reads lastAppliedUpdate and applies to the db, by order, all the updates folowing lastAppliedUpdate, and then updates the value of lastAppliedUpdate in the db. Basically simple.
The issue: the utility successfully applies the needed updates, but then when trying to store the value of lastAppliedUpdate, an error is encountered:
General error: 2014 Cannot execute queries while other unbuffered queries are active. Consider using PDOStatement::fetchAll(). Alternatively, if your code is only ever going to run against mysql, you may enable query buffering by setting the PDO::MYSQL_ATTR_USE_BUFFERED_QUERY attribute.
Any ideas, what does it mean, and how can be resolved?
Below is the essence of the code. It's a php code within the Yii framework.
foreach ($numericlyIndexedUpdateFiles as $index => $filename)
{
$command = new CDbCommand (Yii::app()->db, file_get_contents ($filename));
$command->execute();
}
$metaData = MDbMetaData::model()->find();
$metaData->lastAppliedUpdate = $index;
if (!$metaData->save()) throw new CException ("Failed to save metadata lastAppliedUpdate.");
// on this line, instead of throwing the exception that my code throws, if any,
// I receive the described above error
mysql version is: 5.1.50, php version is: 5.3
edit: the above code is done inside a transaction, and I want it to.
Check it out
PDO Unbuffered queries
You can also look at the to set PDO:MYSQL_ATTR_USE_BUFFERED_QUERY
http://php.net/manual/en/ref.pdo-mysql.php
The general answer is that you have to retrieve all the results of the previous query before you run another, or find out how to turn off buffered queries in your database abstraction layer.
Since I don't know the syntax to give you with these mysterious classes you're using (not a Yii person), the easy fix solution is to close the connection and reopen it between those two actions.
I am a newbie to both PHP and Wordpress (but do ok in C#), and am struggling to understand the error handling in a custom plugin I am attempting to write. The basics of the plugin is to query an exsiting MSSQL database (note its not the standard MYSQL db...) and return the rows back to the screen. This was working well, but the hosting provider has taken my database offline, which led me to the error handling problem (which I thought was ok).
The following code is failing to connect to the database (as expected), but puts an error onto the screen and stops the page processing. It does not even output the 'or die' error text.
QUESTION: How can I just output a simple "Cant load data" message, and continue on normally?
function generateData()
{
global $post;
if ("$post->post_title" == "Home")
{
try
{
$myServer = "<servername>";
$myUser = "<username>";
$myPass = "<password>";
$myDB = "<dbName>";
//connection to the database
$dbhandle = mssql_connect($myServer, $myUser, $myPass)
or die("Couldn't open database $myDB");
//... query processing here...
}
catch (Exception $e)
{
echo "Cannot load data<br />";
}
}
return $content;
}
Error being generated: (line 31 is $dbhandle = mssql_connect...)
Warning: mssql_connect() [function.mssql-connect]: Unable to connect to server: <servername> in <file path> on line 31
Fatal error: Maximum execution time of 30 seconds exceeded in <file path> on line 31
First of all, if mssql_connect raises a warning when there's a problem, there is not much you can do to avoid it : the only thing you could do is hide it, using the # operator :
if (($dbhandle = #mssql_connect($myServer, $myUser, $myPass)) === false) {
// connection failed
}
Note : you should not die() when a connection error occurs : it'll stop the execution of the whole application, which is most certainly not desired.
The Fatal Error is a second problem (which is probably a consequence of the first one).
Note that you cannot recover from a Fatal Error : it is Fatal. Which means you must avoid it, one way or another.
Here, the error is that your script is working for more than max_execution_time seconds ; as the error is reported on the mssql_connect line, I suppose the script is waiting for the connection to succeed, and it doesn't get etablished in less that 30 seconds.
I don't have an SQL Server database to test, but looking at the Runtime Configuration section of the manual for mssql, I'd say that these look interesting :
name Default value
mssql.connect_timeout "5"
mssql.timeout "60"
You could try changing those,
either in your php.ini file, if you can modify it
or using ini_set() before trying to connect.
In the second case, something like this might do the trick :
ini_set('mssql.connect_timeout', '3');
ini_set('mssql.timeout', '3');
You may also want to look at WP_Error Class for handling your errors in an elegant manner. Note that this is a generic approach & that you will have to handle the particular error detection logic separately. WP_Error will help you in gathering all the errors in one place.
I'm trying to connect to an Oracle DB which is currently offline. When it's online it's not a problem, however, now that it's offline my program is getting hung up on the $connection = oci_connect() line and timing out. How do I simply check the connectio and bail out if it's not there?
Try this (fill in your ip and port):
if ( #fsockopen($db_ip,$db_port ) ) {
//connect to database
} else {
// didn't work
}
This gives you both a manual error, plus will return the actual error.
$connection = oci_connect() or die("Critical Error: Could not connect to database.\n\n". oci_error());
Make sure to test this as hopefully the Oracle error doesn't do something stupid like return the connection string (with your DB password) but I wouldn't assume until you see for yourself.
You could select null from dual.
OK, now I see what your asking, I think.
You want to know how to tell if a database is up before you connect to it?
You can use TNSPING to see if a database is up... ok, maybe that's not 100% accurate but it's a good indicator. go to a command prompt and type TNSPING and hit enter. So then you have to figure out how to call a command line tool from PHP.
Here is what I do in ASP.NET
Dim OracleConn As New OracleConnection(YOUR CONNECTION STRING HERE)
Try
OracleConn.Open()
OracleConn.Close()
Catch ex As Exception
Session("ErrorMessage") = "OracleConn: " & ex.Message
Response.Redirect("AccessDenied.aspx")
End Try
It doesnt necessarily say the DB is offline, but an exception will occur if the connection cannot be opened