PHP mysqli code to update data

This article is created to describe the way to update or modify specific data using PHP mysqli script. These are the two approaches, that can be used to update any specific or all data in the database:

• Using PHP mysqli object-oriented script
• Using PHP mysqli procedural script

Whatever the approach we choose to update the data, we need to follow these simple steps:

• Open a connection to the database.
• Write an SQL statement regarding the data modification.
• Initialize the written SQL statement to a variable.
• Use this variable to perform the query against the database to modify particular data.
• Close the database connection.

The SQL statement to update specific data is:

UPDATE tableName
SET column1=value1, column2=value2, column3=value3, ..., columnN=valueN
WHERE particularColumn=particularValue;

Be careful when updating the data. The WHERE clause is used when we need to update particular records.

Be careful when omitting the WHERE clause; update all records in the table.

Update data using PHP mysqli Object-Oriented Script

Follow the example given below to update particular data (a record or row) using a PHP mysqli object-oriented script. In this example, I am going to update the age of a record whose id is 3.

<?php
   $servername = "localhost";
   $username = "root";
   $password = "";
   $dbname = "codescracker";
   
   $conn = new mysqli($servername, $username, $password, $dbname);
   
   if($conn->connect_errno)
   {
      echo "Connection to the database failed!<BR>";
      echo "Reason: ", $conn->connect_error;
      exit();
   }
   
   $sql = "UPDATE customer SET age='40' WHERE id=3";
   
   $result = $conn->query($sql);
   if($result)
   {
      echo "Data updated successfully.";
      
      // block of code to process further...
   }
   else
   {
      echo "Error occurred while updating the record!<BR>";
      echo "Reason: ", $conn->error;
   }
   $conn->close();
?>

Before executing the above PHP script, here is a snapshot of the table customer:

Here is the output produced by the above PHP example on updating the record using a PHP mysqli object-oriented script:

And following is the snapshot of the table named "student" after executing the above PHP script:

Note: The mysqli() function is used to open a connection to the MySQL database server in object-oriented style.

Note: The new keyword is used to create a new object.

Note: The connect_errno is used to get or return the error code (if any) from the last connect call in object-oriented style.

Note: The connect_error is used to get the error description (if any) from the last connection in object-oriented style.

Note: The exit() function is used to terminate the execution of the current PHP script.

Note: The query() function is used to perform queries on the MySQL database in object-oriented style.

Note: The error is used to return the description of the error (if any) from the most recent function call in object-oriented style.

Note: The close() function is used to close an opened connection in object-oriented style.

Note: If you remove the WHERE clause from the above PHP script, then the age column of all rows will be set to 40.

The above example can also be written as:

<?php
   $conn = new mysqli("localhost", "root", "", "codescracker");
   
   if(!$conn->connect_errno)
   {
      if($conn->query("UPDATE customer SET age='40' WHERE id=3"))
         echo "Data updated successfully.";
   }
   $conn->close();
?>

Update data using PHP mysqli procedural script

To update data using a PHP mysqli procedural script, follow the example given below:

<?php
   $conn = mysqli_connect("localhost", "root", "", "codescracker");
   
   if(!mysqli_connect_errno())
   {
      $sql = "UPDATE customer SET age='42' WHERE id=3";
      
      if(mysqli_query($conn, $sql))
         echo "Data updated successfully.";
      else
      {
         echo "Error occurred while updating the record!<BR>";
         echo "Reason: ", mysqli_error($conn);
      }
   }
   mysqli_close($conn);
?>

Note: The mysqli_connect() function is used to open a connection to the MySQL database server in procedural style.

Note: The mysqli_connect_errno() function is used to get or return the error code (if any) from the last connect call in procedural style.

Note: The mysqli_query() function is used to perform queries on the MySQL database in procedural style.

Note: The mysqli_error() function is used to return the description of the error (if any) from the most recent function call in procedural style.

Note: The mysqli_close() function is used to close an opened connection to the MySQL database in procedural style.

PHP mysqli Object-Oriented: Update Multiple Columns

To update multiple columns at once, everything will be the same as done in the section Update Data using PHP mysqli Object-Oriented Script, except the SQL statement. That is, to update two columns, say age and email, use the following SQL statement:

$sql = "UPDATE customer SET age='42', email='newmail@xyz.com' WHERE id=3";

And to update more columns, say three columns, use the following SQL statement:

$sql = "UPDATE customer SET name='Lucas', age='42', email='newmail@xyz.com' WHERE id=3";

Here is the complete PHP mysqli script to update multiple columns at once:

<?php
   $conn = new mysqli("localhost", "root", "", "codescracker");
   
   if(!$conn->connect_errno)
   {
      $sql = "UPDATE customer SET name='Lucas', age='42', email='newmail@xyz.com' WHERE id=3";
      
      if($conn->query($sql))
         echo "Data updated successfully.";
      else
      {
         echo "Error occurred while updating the record!<BR>";
         echo "Reason: ", $conn->error;
      }
   }
   $conn->close();
?>

PHP mysqli Procedural: Update Multiple Columns

<?php
   $conn = mysqli_connect("localhost", "root", "", "codescracker");
   
   if(!mysqli_connect_errno())
   {
      $sql = "UPDATE customer SET name='Lucas', age='42', email='newmail@xyz.com' WHERE id=3";
      
      if(mysqli_query($conn, $sql))
         echo "Data updated successfully.";
      else
      {
         echo "Error occurred while updating the record!<BR>";
         echo "Reason: ", mysqli_error($conn);
      }
   }
   mysqli_close($conn);
?>

PHP mysqli: Update All Rows at Once

To update all rows using the PHP mysqli script, all the processes will be the same, except that you will remove or omit the WHERE clause. That is, to update all rows with particular columns, use this similar SQL statement:

$sql = "UPDATE customer SET email='newmail@xyz.com'";

And to update all rows with multiple columns, use this similar SQL statement:

$sql = "UPDATE customer SET name='Lucas', age='42', email='newmail@xyz.com'";

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