Delete record on database through PHP button - php

I'm trying to add a delete button on a table row, once the user clicks it, I want it to delete the record on the mysql database and therefore, not show on the table. My problem is when I click the delete button, I get a connection error! message, here's my php code:
<?php
$id = $_GET['id'];
$dbc = mysqli_connect('localhost','user','pass','db') or die('Connection error!');
$query = "DELETE FROM table WHERE id = '$id'";
mysqli_query($dbc, $query) or die('Database error!');
\header('location:datapull.php');
?>
thanks for any help in advance...

Solution:
Step1. Over check: localhost,user,pass and db
Step2: Check privilege of user on your database.
If it does not work, I am over-sure that there is problem in your server. At that case contact with customer support of your server.

Double check your database username, password and database name.
Try this code and reply me with what you are getting.
$id = $_GET['id'];
$dbc = mysqli_connect('localhost','user','pass','db') or die('Connection error!');
//Variables inside single quotes wont work. Change to this
$query = "DELETE FROM table WHERE id = '".$id."'";
mysqli_query($dbc, $query) or die('Database error!');
// Check how many rows is affected. If it is returns 0 it is not working. Else it will return how many rows is deleted.
printf("Records deleted: %d\n", mysqli_affected_rows($dbc));
exit;

Related

Display an int value from SQL database using PHP

I'm busy with a school project where I need to register users. I created the database and added the tables and can add users. What I just can't get right is to display the next available user id in the table.
I'm using php to retrieve the highest value but when I use echo the variable won't show. There is no error, there is no output at all, just the rest of the page.
Here is the code:
<?php
$db = mysqli_connect('localhost', 'root', '', 'design');
$query = "SELECT MAX(userid) AS userid FROM users" or
die(mysql_error());
$highest_id = mysqli_query($db, $query);
echo $highest_id;
?>
The code successfully connects to the database, the column is called userid, it contains int values and there are other columns as well.
All other code in the script runs perfectly, it's just this part that I can't get to work.
I have spent the last two days reading and searching for answers and I am at my wits end. Any help would be appreciated.
Thank you.
could be your table is User and not Userid
$query = "SELECT MAX(userid) AS userid FROM users"
Anyway for fetching you should use eg:
$result = mysqli_query($db, $query);
$row=mysqli_fetch_array($result,MYSQLI_NUM);
echo $row[0];
The mysqli_query returns a general object that contains the results array. You have to use the mysqli_fetch_row.
<?php
$db = mysqli_connect('localhost', 'root', '', 'design');
$query = "SELECT MAX(userid) AS userid FROM userid" or die(mysql_error());
$highest_id_query = mysqli_query($db, $query);
var_dump($highest_id_query); // so you could check the object attributes
//loop results from query
while($row=mysqli_fetch_row($highest_id_query)){
$highest_id = $row['userid'];
echo $highest_id;
}
?>
You could also use the sql statement: SELECT COUNT(*) FROM userid
Be sure to name your tables correctly! SELECT COUNT(*) FROM users

How to get data from a different database and save it to another database

I don't know if this problem of mine is possible. Is it? I have a library system. I add and edit new books in the Catalog Database. In other words, the Catalog Database is for adding/editing books only. I have another Database (not table) for Borrowing Books. I want to store these books, which are viewed through Catalog DB, to Borrowing DB.
I have a snippet for getting data from Catalog DB
error_reporting(0);
$con = mysql_connect("localhost","root","");
mysql_select_db("catalog", $con);
$acc_number=$_GET["acc_number"];
$query="select * from branch where acc_number = '$acc_number'";
$result=mysql_query($query);
while ($row = mysql_fetch_array($result)) {
//echo $row[1];
}
<textarea name="title" disabled><?php echo $row[1];?></textarea>
And a button for the submission (store to borrowing database). If button is clicked, it's where my problem occurs. I just got a blank page after submitting it. Here is my process.php:
$con = mysql_connect("localhost","root","");
mysql_select_db("catalog", $con);
$acc_number = $_POST['acc_number'];
$title = $_POST['title'];
$sql = mysql_query("select * from books where acc_number='$acc_number'");
while($row=mysql_fetch_array($sql)){
$con = mysql_connect("localhost","root","");
mysql_select_db("borrowing", $con);
$query="INSERT INTO borrowers (title) VALUES ('$title')";
mysql_query($query);
if($query){
header("Location:../librarysystem/books.php");
}
}
You need to create two sql connections, one for each DB. Then simply get the data from one DB (perform operations, if required) and write to the second DB.
First, I suggest that you use MYSQLI or DO since MYSQL is deprecated.
These are suggestions not a fix.
Use only one connect function, you don't need two of them just use the same variable $con.
Add some error checks in there to make sure you are connecting properly
$sql = mysql_query("select * from books where acc_number='$acc_number'") or die ("error message here");
For this
$query="INSERT INTO borrowers (title) VALUES ('$title')";
mysql_query($query);
if($query){
header("Location:../librarysystem/books.php");
}
Try
$query=mysql_query("INSERT INTO borrowers (title) VALUES ('$title')") or die("Could not insert...");
if($query){
header("Location:../librarysystem/books.php");
}
You have two approaches for this:
Create two separate DB connections and manipulate data there. Passing $conn as connection to MySQL queries will work.
Use the same database using different DB prefixes. Say for example, for first DB it should be
mb_ (Manage Books)
and
bb_ (Borrow Books)
If I were at your place, I would have preferred second approach.

record won't delete from database

I am trying to delete a record using php from a database. This is supposed to happen when I click a button, no error is displayed and the query appears on the screen but the record remains on the database
phpmyadmin gives me the following code to use: DELETE FROM 'the shop'.'customer' WHERE 'customer'.'CustomerID' = 8
<?php
$host="localhost"; // Host name
$tbl_name="customer"; // Table name
$db_user="root";
$db_pass="";
$connect = mysql_connect("$host", "$db_user", "$db_pass");
$db_name="the_shop"; // Database name
mysql_select_db("$db_name");
if (!$connect)
{
die("MySQL could not connect!");
}
if(isset($_GET['submit2'])){
$db_username = $_GET['username'];
$sql4 = "DELETE FROM 'the_shop'.'customer' WHERE 'customer'.'CustomerID' = 8"
or die('error deleting record');
mysql_query($sql4);
echo $sql4;
}
?>
I know this will only delete the record that has a CustomerID that = 8
my intention is that once this works I will replace CustomerID with Username and the '8' with the relevant variable that will be given a value via a form
any help is appreciated
You are using quotes instead of back tick
$sql4 = "DELETE FROM `the_shop`.`customer` WHERE `customer`.`CustomerID` = 8";
Moreover you don't need back ticks(In this case as you are not using any Reserved keywords here) as well as you are using die() at wrong place
Use this,It is working.
<?php
$host="localhost"; // Host name
$tbl_name="customer"; // Table name
$db_user="root";
$db_pass="";
$connect = mysql_connect("$host", "$db_user", "$db_pass");
$db_name="the_shop"; // Database name
mysql_select_db("$db_name",$connect);
if (!$connect)
{
die("MySQL could not connect!");
}
if(isset($_GET['submit2'])){
$db_username = $_GET['username'];
$sql4 = "DELETE FROM `the_shop`.`customer` WHERE `customer`.`CustomerID` = 8";
mysql_query($sql4,$connect) or die('error deleting record');
echo $sql4;
}
?>
Your statement is not correct. You use quoted instead of back ticks. But you can make your statement easier.
$sql4 = "DELETE FROM customer WHERE CustomerID = 8";
$sql4 = "DELETE FROM `the_shop`.`customer` WHERE `customer`.`CustomerID` = 8"
mysql_query($sql4);or die('error deleting record');
echo $sql4;
You don't need to specify which database to query in your query.
This will suffice:
DELETE FROM customer WHERE CustomerID = 8
The Mysql extension is deprecated. This means that it is no longer supported by PHP and should not be used. Try mysqli or pdo instead.
You can just use this. There is no need for you to specify the database.
delete from customer where CustomerID = 8

mysql_insert_id() not returning a value -

I need to retrieve the auto increment field from my database table. I tried the following but $id is always just empty.
The insert works too.
My table is as follows:
idint(9) NOT NULL auto_increment,
and id is set as primary
What am I doing wrong?
$conn = mysql_connect($host,$username,$password);
mysql_select_db($database, $conn) or die( "Unable to select database");
include "update_activity.php";
updateActivity("logged in", "On Break");
$date = date("m/d/y"); $starttime = time();
$sesh = $_SESSION['fname']." ".$_SESSION['lname'];
$q = "INSERT INTO `breaks` (date, starttime, user) VALUES ('".$date."', '".$starttime."', '".$sesh."')";
$query = mysql_query($q, $conn);
$id = mysql_insert_id($conn);
echo var_dump($id); exit;
edited to show my more recent attempts
Have read all comments given and your replies to each.
Only one of these is possible:
Either the query works properly OR
You are not getting the generated primary key.
Both of these can never be true.
Define, how you know query is working? Do you know the max PK before and after the running query? Is the insert happening from some other place or thread or even other user? the query is working properly from code or from your mysql client?
To diagnose the problem, we have to go though the normal way.
Dump your generated query before calling mysql_query.
Wrap a error checking system around your query call so php can tell you if the query worked or not. I am sure just by these two steps you will realize the root cause of the problem.
error_reporting(E_ALL);
ini_set('display_errors','on');
echo "before calling: $q\n";
$query = mysql_query($q, $conn);
if(!$query)
{
echo "Error:" . mysql_error($conn);
return;
}
echo " generated id:" . mysql_insert_id($conn);
#adelphia as far as i get the idea there is a problem in the query that is executed.
plz check the query properly
Borrow a lead from this code extracted from here:
http://php.net/manual/en/function.mysql-insert-id.php
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');
mysql_query("INSERT INTO mytable (product) values ('kossu')");
printf("Last inserted record has id %d\n", mysql_insert_id());
?>
The problem with your insert query
$q = "INSERT INTO `breaks` (date, starttime, user)
VALUES ('".$date."',
'".$starttime."',
'".$_SESSION['fname'] $_SESSION['lname']."')";
try with this
and main thing you are using most of the deprecated "mysql" things like "mysql_insert_id()"
store the values that u want to pass into an array or variable and pass it in the insert query.
its should work fine then...

insert into mysql problem

i have a field in table opt named confirm of type tinyint. i want to insert value(1) by this statement but it is not working can any one help??
$connect= mysql_connect("localhost","root") or die ("Sorry, Can not connect to database");
mysql_select_db("login") or die (mysql_error());
$user=$_POST['staff'];
echo $user;
$query="SELECT * from users where username='$user' ";
$result=mysql_query($query,$connect) or die(mysql_error());
$row=mysql_fetch_array($result);
$uid=$row['userid'];
echo $uid;
$query="SELECT * from opt where userid='$uid' ";
$result=mysql_query($query,$connect) or die(mysql_error());
$row=mysql_fetch_array($result);
if($row['confirm']==0)
{
$query = "INSERT INTO opt (confirm) values(1)";
echo 'The user selected options has confirmed';
}
?>
You are not executing the query.
add an extra
$result=mysql_query($query,$connect) or die(mysql_error());
after the line
$query = "INSERT INTO opt (confirm) values(1)";
Apart from not executing the "InSERT STATEMENT",
You should probably be using an
"UPDATE OPT SET CONFIRM = '1' WHERE USERID = $user;"
as the row already exists ('cause you managed to select it!).
$query is a variable and there's no reason that it would cause a record to magically get inserted into the opt table.
You need to insert the following line after $query = "...":
mysql_query($query);
Also, I hopethat's not the code you're running in production.
You need to have the following somewhere:
$user = mysql_real_escape_string($user);
Why is not working? what error is throwing?
Check the other fields of the table...

Categories