Database APIs and Wrappers

MySQL, MySQLi, PDO, PG, OCI, SQLSRV

Ivan YonkovTechnical Trainerhttp://github.com/RoYaLBGSoftware Universityhttp://softuni.bg

Web Development Basics

Table of Contents

1. What is a DB API?

2. Various DB Extensions in PHP

1. Mysql – deprecated

2. Mysqli

3. Pg – Postgre SQL

4. Oci – Oracle

5. PDO – Various DB access interface

3. Using PDO2

Database API

What is Database API?

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Database API is the public interface provided to communicate with certain database. It could be a set of functions, classes and methods which perform actions against the database through a desired language.

Various Database Extensions

Various Database API’s PHP can natively communicate to a lot of databases through its

standard library (yet some extensions are required) MySQL database

Oracle database

Postgre database

SQLite database

MS SQL Server database

Etc…

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MySQL Extension The MySQL Extension is the oldest API for communicating to

MySQL Server It’s been there for more than 15 years (PHP 4.0), marked as

deprecated and removed as of PHP 7.0 Uses standard php global functions prefixed with mysql_ Communicates natively with MySQL and sends plain queries Very vulnerable and error prone

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MySQL Extension (2)

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mysql_connect(“localhost”, “root”, “”, “forum”);

$result = mysql_query(“SELECT * FROM topics”);

while ($row = mysql_fetch_assoc($result)) {echo $row[‘body’] . “<br />”;

}

MySQLi Extension The MySQLi Extension is the de facto PHP’s standard succeedor

of the MySQL extension Provides both Object oriented and Procedural style

OOP way – the mysqli class. Procedural – the mysql_ prefix

Still uses old PHP style method naming (under_scored) Supports a way of parameter binding

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MySQLi Extension (2) [Procedural]

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$conn = mysqli_connect(“localhost”, “root”, “”, “forum”);

$result = mysqli_query($link, “SELECT * FROM topics”);

while ($row = mysqli_fetch_assoc($result) {echo $row[‘body’] . “<br/>”;

}

MySQLi Extension (3) [OOP]

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$mysqli = new mysqli(“localhost”, “root”, “”, “forum”);

$result = $mysqli->query(“SELECT * FROM topics”);

while ($row = $result->fetch_assoc()) {echo $row[‘body’] . “<br/>”;

}

PDO

PDO PDO (PHP Data Objects) like Java Data Objects, provides consistent

interface for accessing different databases through db drivers Has full OOP support Supports prepared statements Good method naming and consistent objects Can reuse code after driver changes if the SQL dialect is the same

One can use the same methods no matter the driver Does not rewrite SQL or missing features

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PDO (2)

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$dbh = new PDO($dsn, $user, $pass);

The DSN is a connection string providing the driver, host and database name if present. MySQL dsn: “mysql:host=localhost;dbname=forum” SQLite dsn

File: “sqlite:/home/royal/databases/sqlite/mysqlitedb.sq3” Memory: “sqlite::memory:”

PDO (3)

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$dbh = new PDO(“mysql:host=localhost;dbname=forum”, “root”, “”

);

PDO (4)

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/** @var \PDOStatement $sth */$id = $_GET[‘id’];$sth = $db->prepare(“SELECT * FROM topics WHERE id = ?”);$sth->bindParam(1, $id, PDO::PARAM_INT);$sth->execute();$topic = $sth->fetch();echo $topic[‘body’];

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Summary

1. What is a DB API?

2. Various DB Extensions in PHP

1. Using mysql_* extension (don’t)

2. Using mysqli_* extension

3. Using PDO

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Questions?

Database APIs and Wrappers

https://softuni.bg/courses/web-development-basics/

License

This course (slides, examples, demos, videos, homework, etc.)is licensed under the "Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International" license

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Attribution: this work may contain portions from "Fundamentals of Computer Programming with C#" book by Svetlin Nakov & Co. under CC-BY-SA license

"C# Part I" course by Telerik Academy under CC-BY-NC-SA license

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