Learning PHP Data Objects: A Beginner's Guide to PHP Data Objects, Database Connection Abstraction Library for PHP 5

Learning PHP Data Objects: A Beginner's Guide to PHP Data Objects, Database Connection Abstraction Library for PHP 5

Dennis Popel

Language: English

Pages: 116

ISBN: 2:00097487

Format: PDF / Kindle (mobi) / ePub

This book starts with an overview of PHP Data Objects (PDO), followed by getting started with PDO. Then it covers error handling, prepared statements, and handling rowsets, before covering advanced uses of PDO and an example of its use in an MVC application. Finally an appendix covers the new object-oriented features of PHP 5. This book will guide you through the data layer abstraction objects in PHP. PHP developers who need to use PDO for data abstraction.

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using exceptions. Every failed call to any of the PDO or PDOStatement methods will throw an exception. As we have previously noted, PDO uses the silent mode, by default. To switch to a desired error handling mode, we have to specify it by calling PDO::setAttribute() method. Each of the error handling modes is specified by the following constants, which are defined in the PDO class: PDO::ERRMODE_SILENT - the silent strategy. PDO::ERRMODE_WARNING - the warning strategy. PDO::ERRMODE_EXCEPTION -

$stmt->bindValue(':first', $author['firstName']); $stmt->bindValue(':last', $author['lastName']); $stmt->bindValue(':bio', $author['bio']); $stmt->execute(); } As you can see, in both cases we don't supply anything in the call to PDOStatement::execute(). Again, as with unbound statements, if you don't bind a value for every placeholder, the call to PDOStatement::execute() will fail, leading to an exception. PDO can also bind result set columns to PHP variables for SELECT queries. These

there is no error. // We can return back to books listing header("Location: books.php"); exit; } catch(PDOException $e) { $warnings[] = 'Duplicate ISBN entered. Please correct'; } As we can see, the part that constructs the query is very long. With a prepared statement, this code snippet can be rewritten as follows: if(@$book['id']) { $sql = "UPDATE books SET title=?, author=?, isbn=?, publisher=? year=?, summary=? WHERE id=$book[id]"; } else { $sql = "INSERT INTO books(title, author, isbn,

fails and throws an exception, we will not be able to call any methods on the $conn variable (this will lead to a fatal error—calling member functions on non-objects are fatal errors.) Since all pages in our application call the showFooter() method function, this change will be visible everywhere: MySQL Buffered Queries If you are working with a MySQL database only, then you may want to employ MySQL's PDO driver buffered query mode. When the connection is set to the buffered query

overwrite the ID column value selected from the books table. Other methods in the Book class rely on the value in the id field being correct and may lead to severe data corruption if this value is incorrect. Another file that we should now modify is authors.php:

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