Basic use of PDO

1, database design

create table book(

id int(4) not null primary key auto_increment,

name varchar(255) not null,

author varchar(255) not null)

CHARSET=utf8;

2, insert test data

Database display:

##3. Set the database connection variables

<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2018/3/5 0005
 * Time: 上午 9:23
 */
header("content-type:text/html;charset=utf-8");
//mysql:host:localhost;port=3306;dbname=php;charset=utf-8
$dbms='mysql';
$host='localhost';
$port='3306';
$dbname='php';
$charset='utf-8';
//用户名与密码
$user='root';
$pwd='root';
$dsn="$dbms:host=$host;port=$port;dbname=$dbname;charset=$charset";

4, PDO connects to the database

<?php
try{
    $pdo=new PDO($dsn,$user,$pwd);
}catch (PDOException $exception){
    echo $exception->getMessage().'<br>';
}

5, executes the sql statement and prints

$sql='select *from book';
$result=$pdo->query($sql);
$row=$result->fetchAll();
echo "<pre>";
print_r($row);
echo "</pre>";

In actual operation, sometimes you only need to get the index array. In this case, you only need to change the fetchAll() function. The parameters can be
## Code:

<?php
$row=$result->fetchAll(PDO::FETCH_ASSOC); //获取索引数组

If you want to get the value of the second column of the database, the code is as follows:

<?php
$row=$result->fetchAll(PDO::FETCH_COLUMN,1);//获取第二列的所有值