PHP connections to different databases: MySQL, PostgreSQL, Oracle and more

PHP Connection Database Guide: MySQL: Install the MySQLi extension and create a connection (servername, username, password, dbname). PostgreSQL: Install the PgSQL extension and create a connection (host, dbname, user, password). Oracle: Install Oracle OCI8 extension and create connection (servername, username, password). Practical case: Obtain MySQL data, PostgreSQL query, Oracle OCI8 update record.

PHP Connecting to different databases

Using PHP to connect to different databases is a skill that any web developer must master . This article will guide you on how to use PHP to connect to popular databases like MySQL, PostgreSQL, and Oracle.

Connect to MySQL

Step 1: Install the MySQLi extension

sudo apt-get install php7.2-mysqli

Step 2: Create a connection

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "mydb";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接
if ($conn->connect_error) {
  die("连接失败: " . $conn->connect_error);
}

Connect to PostgreSQL

Step 1: Install PgSQL extension

sudo apt-get install php7.2-pgsql

Step 2: Create connection

$servername = "localhost";
$username = "postgres";
$password = "my_password";
$dbname = "mydb";

// 创建连接
$conn = pg_connect("host=$servername dbname=$dbname user=$username password=$password");

// 检查连接
if (!$conn) {
  die("连接失败: " . pg_last_error($conn));
}

Connect to Oracle

Step 1: Install Oracle OCI8 extension

sudo apt-get install php7.2-oci8

Step 2: Create a connection

$servername = "localhost/orcl";
$username = "oracle_user";
$password = "my_password";

// 创建连接
$conn = oci_connect($username, $password, $servername);

// 检查连接
if (!$conn) {
  $e = oci_error();
  die("连接失败: " . $e['message']);
}

Practical case

Get data from MySQL table

$sql = "SELECT * FROM users";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
  // 输出数据
  while($row = $result->fetch_assoc()) {
    echo "id: " . $row["id"] . " - Name: " . $row["name"] . "<br>";
  }
} else {
  echo "没有数据";
}

Use PostgreSQL query

$sql = "SELECT * FROM users WHERE id > 10";
$result = pg_query($conn, $sql);

if (pg_num_rows($result) > 0) {
  // 输出数据
  while($row = pg_fetch_assoc($result)) {
    echo "id: " . $row["id"] . " - Name: " . $row["name"] . "<br>";
  }
} else {
  echo "没有数据";
}

Use Oracle OCI8 update Record

$sql = "UPDATE users SET name = 'John Doe' WHERE id = 1";
$stmt = oci_parse($conn, $sql);

if (oci_execute($stmt)) {
  echo "记录更新成功";
} else {
  echo "更新记录失败";
}

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