2

Below is a documented code example showing how to use the PDO classes/objects to connect and query your database (and check for errors).

If there are any questions, or you want to see different features, let me know.

UPDATE: I've encountered a problem with PDO and bit fields (MySQL). If you experience any problems with those I suggest changing the column type to TINYINT(1).

Edited by pritaeas

<?php
    // define a variable to switch on/off error messages
    $pdoDebug = true;

    try {
        // connect to your database
        $pdo = new PDO('mysql:dbname=mydatabase;host=localhost', 'myuser', 'mypassword');
    }
    catch (PDOException $exception) {
        // unlike mysql/mysqli, pdo throws an exception when it is unable to connect
        echo '<p>There was an error connecting to the database!</p>';
        if ($pdoDebug) {
            // pdo's exception provides more information than just a message
            // including getFile() and getLine()
            echo $exception->getMessage();
        }
    }

    if ($pdoDebug) {
        // $pdo->query() returns FALSE if there is an error
        // to get more information, the following will enable exceptions
        $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    }

    // create a query that should return a single record
    // the backticks around the table and column names are optional
    // they are required only when a name matches a reserved word (e.g. `date`)
    $query = 'SELECT * FROM `mytable` ORDER BY `mycolumn` LIMIT 1';

    // execute the query
    // query returns FALSE on error, and a result object on success
    try {
        $pdoStatement = $pdo->query($query);
    }
    catch (PDOException $exception) {
        // the query failed and debugging is enabled
        echo "<p>There was an error in query: $query</p>";
        echo $exception->getMessage();
        $pdoStatement = false;
    }

    if ($pdoStatement) {
        // the query was successful
        // get the result (if any)
        // fetchObject returns FALSE if there is no record
        if ($recordObj = $pdoStatement->fetchObject()) {
            // we have a record so now we can use it
            // the columns are properties of the object
            echo $recordObj->mycolumn;
        }
        else {
            echo '<p>No record found.</p>';
        }

        // when you are done with the statement, close it
        $pdoStatement->closeCursor();
    }

    // now get multiple records
    $query = 'SELECT * FROM `mytable` ORDER BY `mycolumn` LIMIT 10';

    try {
        $pdoStatement = $pdo->query($query);
    }
    catch (PDOException $exception) {
        // the query failed and debugging is enabled
        echo "<p>There was an error in query: $query</p>";
        echo $exception->getMessage();
        $pdoStatement = false;
    }

    if ($pdoStatement) {
        // perhaps you want to check if there are any rows available
        if ($pdoStatement->rowCount() == 0) {
            echo '<p>No records found.</p>';
        }
        else {
            while ($recordObj = $pdoStatement->fetchObject()) {
                echo $recordObj->mycolumn;
            }
        }

        $pdoStatement->closeCursor();
    }

    // clean up any objects
    unset($pdoStatement);
    unset($pdo);
?>
2
Contributors
1
Reply
70
Views
5 Years
Discussion Span
Last Post by sammry
Have something to contribute to this discussion? Please be thoughtful, detailed and courteous, and be sure to adhere to our posting rules.