From 614d65c3b76dad6a5d3fe23dacb34400e59eb6f3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E6=A2=81=E6=B5=A9?= <1599724449@qq.com> Date: Mon, 23 May 2022 14:49:10 +0800 Subject: [PATCH] php --- ...02\345\270\270\345\244\204\347\220\206.md" | 4 - "\346\242\201\346\265\251/20220523-mysql.md" | 194 ++++++++++++++++++ 2 files changed, 194 insertions(+), 4 deletions(-) create mode 100644 "\346\242\201\346\265\251/20220523-mysql.md" diff --git "a/\346\242\201\346\265\251/20220518-\346\226\207\344\273\266\344\270\212\344\274\240\345\222\214\345\274\202\345\270\270\345\244\204\347\220\206.md" "b/\346\242\201\346\265\251/20220518-\346\226\207\344\273\266\344\270\212\344\274\240\345\222\214\345\274\202\345\270\270\345\244\204\347\220\206.md" index 234e2b0..788c8dd 100644 --- "a/\346\242\201\346\265\251/20220518-\346\226\207\344\273\266\344\270\212\344\274\240\345\222\214\345\274\202\345\270\270\345\244\204\347\220\206.md" +++ "b/\346\242\201\346\265\251/20220518-\346\226\207\344\273\266\344\270\212\344\274\240\345\222\214\345\274\202\345\270\270\345\244\204\347\220\206.md" @@ -222,11 +222,7 @@ $_COOKIE-> 用于绘画控制 $_ENY-> 服务器端环境变量 -**调错** -显示错误代码 - -$_ERROR() # 作业 diff --git "a/\346\242\201\346\265\251/20220523-mysql.md" "b/\346\242\201\346\265\251/20220523-mysql.md" new file mode 100644 index 0000000..f1ed0c6 --- /dev/null +++ "b/\346\242\201\346\265\251/20220523-mysql.md" @@ -0,0 +1,194 @@ +# PHP操作MySQL + +### 1、掌握php访问数据库的基本步骤 + +**连接数据库服务器** + +**选择数据库** + +​ 连接mysql服务器同时选择数据库 + +​ mysqli_connect(host服务器地址,username用户名，password密码，dbname数据库名称，port端口，socket) + +```php +$conn = mysqli_connect('localhost','lh','123456','student'); +//变量未知，用var_dump来查看， +var_dump($conn); +//或者用if返回对象或错误 +if($conn){ + echo "连接成功"; +}else{ + die("连接失败，错误".mysqli_connect_error()); +} +``` + + + +​ 连接mysql服务器，再连接数据库 + +​ mysqli_connect(host服务器地址,username用户名，password密码) + +​ mysqli_select_db($link,db_name) + +```php +error_reporting(E_ALL ^ E_WARNING);//^表示排除，隐藏所有错误，除了warning警告 +$a = mysqli_connect('localhost','lh','123456'); +if(!$a){ + die("连接失败，错误".mysqli_connect_error()); +} +$b = mysqli_select_db($a,'student'); +if(!$b){ + die("连接数据库失败，错误".mysqli_error($a)); +} +echo "数据库连接成功"; +``` + + + +## 2、掌握MySQL扩展函数 + +**执行sql语句** + +增，删，改，查 + +$mysqli_query() + +```mysql +增 +insert into `student` (`name`) values('值'); +删 +delete from `student` where `id`=2; +改 +update `studnet` set `name` = '值' where <条件>; +查 +select * from `student`; +``` + + + +```php +增 +$sql = "insert into `student<表名>`(`name<字段名>`) values('值')"; +//$result = mysqli_query($conn,$sql); +//if($result){ +// echo "添加成功"; +//}else{ +// echo "添加失败"; +//} +删 +$sql ="delete from `student` where `id`=2"; +//$result = mysqli_query($a,$sql) or die("执行错误".mysqli_error($a)); +//if($result){ +// echo "删除成功"; +//}else{ +// echo "删除失败"; +//} +改 +$sql = "update `student` set `name` ='值' where <条件>"; + +``` + +```php + + +$num = mysqli_affected_rows($a);//返回最近一次query操作受影响的行数，0表示没有受影响的行数，-1表示返回错误，>0表示受影响的行数 + +if($num==0){ + +echo "没有对应数据"; + +}else if($num<0){ + +die("程序失败"); + +}else{ + echo "成功，删除了".$num."行"; +} + + +``` + +**处理结果集** + +```php + +查 +$sql = "select * from `student`"; +$result = mysqli_query($a,$sql) or die("执行错误".mysqli_error($a)); +//返回一个二维数组 +$all_res =mysqli_fetch_all($result); +//返回一行数组，包含索引和关联数组，每次之显示一行，要显示多行要用循环 +$all_res =mysqli_fetch_array($result); +//以关联数组为形式返回一行，每次自动下一行 +$all_res =mysqli_fetch_assoc($result); +//以索引数组为形式返回一行，每次自动下一行 +$all_res =mysqli_fetch_row($result); +//以对象为形式返回一行，每次自动下一行 +$all_res =mysqli_fetch_object($result); + +``` + + + +**关闭连接** + +```php +mysqli_close($conn); +``` + + + + + +# 作业 + +```mysql +create database studentt charset utf8; +use studentt; +create table user( + id int primary key auto_increment, + name varchar(20) not null, + score decimal not null +); +``` + +```php +"; +$b = mysqli_select_db($a,'studentt'); +if(!$b){ + die("连接数据库失败，错误".mysqli_error($a)); +} +echo "数据库连接成功"; +echo "
"; +mysqli_query($a,"set names utf8"); +//增加 +$sql_zj = "insert into `user`(`name`,`score`) values('陈小龙','98.5'),('吴大虫','75.5'),('陈得胜','66')"; +$res_zj = mysqli_query($a,$sql_zj) or die("添加数据失败！错误为：".mysqli_error($a)); + +//删除 +$sql_sc = "delete from `user` where `id`>3"; +$res_sc = mysqli_query($a,$sql_sc) or die("删除数据失败！错误为：".mysqli_error($a)); +//修改 +$sql_xg = "update `user` set `name` = '陈胜' where `id`=3"; +$res_xg = mysqli_query($a,$sql_xg) or die("修改数据失败！错误为：".mysqli_error($a)); +//查询 +$sql_cx = "select * from `user`"; +$res_cx = mysqli_query($a,$sql_cx) or die("执行错误".mysqli_error($a)); +$all_res =mysqli_fetch_assoc($res_cx); +//打印结果 +while($c=mysqli_fetch_assoc($res_cx)){ + echo $c['id']."|".$c['name']."|".$c['score']."
"; +} +``` + + + -- Gitee