When executing SQL query in PHP, no errors are shown but no data can be seen in the database. how to check?
If you’re not seeing any errors in your PHP script when executing an SQL query, but you’re also not seeing any data changes in your database, there are several things you can check to troubleshoot the issue:
- Database Connection: Make sure your PHP script is connected to the correct database. Check the connection parameters, such as the hostname, username, password, and database name. Incorrect connection parameters could result in your queries not affecting the intended database.
- Error Reporting: Even though you might not see errors directly in your script, you can enable error reporting in PHP to display any potential errors that might be occurring. Use the following lines at the beginning of your PHP script:
error_reporting(E_ALL);
This will help you see if there are any syntax or runtime errors in your script that could be preventing the query from executing properly.
ini_set('display_errors', '1');
- Query Execution: Check whether your SQL query is being executed successfully. You can use the
mysqli_query()
function in PHP to execute your query and then check for errors usingmysqli_error()
$query = "YOUR_SQL_QUERY_HERE";
This will help you identify if there's an issue with the query itself.
$result = mysqli_query($connection, $query);
if (!$result) {
die("Query failed: " . mysqli_error($connection));
}- Data Manipulation: If you’re executing an SQL query that modifies data (INSERT, UPDATE, DELETE), make sure that you’re committing the changes to the database. For example, if you’re using the InnoDB storage engine, you need to explicitly commit the changes by running
mysqli_commit($connection)
after executing the query. - Transaction Management: If you’re using transactions, ensure that you’re starting and committing/rolling back transactions properly. If you don’t commit your changes within a transaction, they won’t be saved to the database.
- Check the Affected Rows: After executing an INSERT, UPDATE, or DELETE query, you can check the number of affected rows using the mysqli_affected_rows() function. If it returns 0, it means that the query did not actually affect any rows.
- Check for Auto-Commit Settings: Depending on the configuration of your database driver and connection, auto-commit might be enabled, causing changes to be committed immediately after each query. If you’re expecting to use transactions, make sure auto-commit is disabled.
- Check Database Logs: Check your database logs for any error messages or warnings related to the queries you’re executing. These logs can provide valuable information about what might be going wrong.
By systematically checking these points, you should be able to identify the source of the issue and determine why your data changes are not being reflected in the database.