Why Am I Getting the 'Fatal error: Uncaught exception 'mysqli_sql_exception' with message 'No index used in query/prepared statement'' Error in MySQL?

"Fatal error: Uncaught exception 'mysqli_sql_exception' with message 'No index used in query/prepared statement'" Explained

Introduction

When executing database queries, you may encounter the error "Fatal error: Uncaught exception 'mysqli_sql_exception' with message 'No index used in query/prepared statement'". This article aims to elucidate the underlying causes and provide solutions for this error.

PHP Code Evaluation

$mysql = new mysqli(DB_SERVER, DB_USER, DB_PASSWORD, DB_NAME) or die('There was a problem connecting to the database');
if (mysqli_connect_errno()) {
    printf("DB error: %s", mysqli_connect_error());
    exit();
}

$get_emp_list = $mysql->prepare("SELECT id, name FROM calc");
if(!$get_emp_list){
    echo "prepare failed\n";
    echo "error: ", $mysql->error, "\n";
    return;
}
$get_emp_list->execute();
$get_emp_list->bind_result($id, $emp_list);

Error Analysis

The error message indicates that an index is missing in the query or prepared statement. In this case, the MySQL table "calc" does not have an index on the "id" and "name" columns.

Solutions

Adjust mysqli_report Setting

The mysqli_report() function can be used to control the severity of warnings and errors reported by MySQL. By setting mysqli_report(MYSQLI_REPORT_OFF) or mysqli_report(MYSQLI_REPORT_ERROR), you can disable warnings and only report errors, which will avoid the fatal error in this case.

mysqli_report(MYSQLI_REPORT_OFF);

Implement Error Handling

Another solution is to implement error handling using try{} and catch() blocks. This allows you to catch and handle errors and warnings that occur during database operations.

try {
    $get_emp_list = $mysql->prepare("SELECT id, name FROM calc");
    if(!$get_emp_list){
        throw new Exception("Prepare failed");
    }
    $get_emp_list->execute();
    $get_emp_list->bind_result($id, $emp_list);
} catch (Exception $e) {
    echo "Error occurred: " . $e->getMessage() . "\n";
}

Create Indexes on Table

To address the underlying index issue, you should create indexes on the table to optimize query performance.

CREATE INDEX idx_emp_id ON calc (id);
CREATE INDEX idx_emp_name ON calc (name);

By implementing these solutions, you can resolve the "Fatal error: Uncaught exception 'mysqli_sql_exception' with message 'No index used in query/prepared statement'" error and improve the performance of your database operations.

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