PHP MySQL学习

1、数据库连接

<?php$con = mysqli_connect('127.0.0.1', 'root', 'abc123456');//检查连接是否成功if (!$link){    //注意mysqli_connect_error()新特性    die('Unable to connect!'). mysqli_connect_error();}else{    echo "OK!<br>";}

2、选择数据库

mysqli_select_db()函数

<?php$dbs = mysqli_select_db($link,"ceshi");if($dbs){echo "数据库选择成功";}

3、新建数据库

语法：CREATE DATABASE db_name

<?phpif(mysqli_query($link,"CREATE DATABASE mmydb")){   echo "Database created";}

4、在数据库中建立表

语法：CREATE TABLE table_name

例如：建立一个名为Person的表

<?php$sql = "CREATE TABLE Person(Firstname varchar(15),Lastname varchar(15),Age int)";

5、向表中增添数据

用mysqli_query函数

语法：INSERT INTO table_name

例如：

<?phpmysqli_query($link,"INSERT INTO Person (Firstname, Lastname, Age)VALUES ('Peter','Gr',15)");mysqli_query($link,"INSERT INTO Person (Firstname, Lastname, Age)VALUES ('Glenn','Kl',10)");mysqli_query($link,"INSERT INTO Person (Firstname, Lastname, Age)VALUES ('Hello','Mo',9)");

6、更新数据

用mysqli_query函数

语法：UPDATE table_name SET ...WHERE ...

例如：

mysqli_query($link, "UPDATE Person SET Age = 22 WHERE Firstname='Hello' AND Lastname =  'Mo'");

7、查找

用mysqli_query函数
需要用到mysql的select语句

例如：

<?php$result = mysqli_query($link, "SELECT * FROM Person WHERE Firstname = 'Glenn'");while($row = mysqli_fetch_array($result)){    echo $row[0] . " " . $row[1]." ".$row[2];    echo "<br>";}
输出结果为 Glenn Kl 10

注：

mysqli_fetch_array()是通过数组的方式显示

mysqli_fetch_assoc()是通过键值，关联数组的显示方式
<?php$result = mysqli_query($link, "SELECT * FROM Person WHERE Firstname = 'Glenn'");while($row = mysqli_fetch_assoc($result)){    echo $row['Firstname'] . " " . $row['Lastname']." ".$row['Age'];    echo "<br>";}

8、删除数据

用mysqli_query函数
语法：DELETE FROM table_name WHERE ...

mysqli_query($link, "DELETE FROM Person WHERE Firstname = 'Glenn'");