Native PHP operation database addition, deletion, modification and query

Step one: Create a database and create a data table in the database. Of course, there can be many data tables in a database. Here I will create a table to store the students' personal names and grades.

Recommended mysql video tutorials: "mysql tutorial"

Idea: Connect to the server—>Create database—>Connect to database—>Create data Table

Script: Create database and data table

"; } else { echo "数据库创建失败: " . mysql_error()."
"; } //连接数据库studentinfo $sele=mysql_select_db( 'studentinfo' ); if(!$sele){ die("连接数据库失败: ".mysql_error());//连接数据库失败退出程序 } // 创建数据表命名为student，主键为id(不为空整型)，变量名为name(255位不为空字符串)，变量名为chinese(4位不为空整型) // 变量名为english(4位不为空整型)，变量名为math(4位不为空整型) $sql_table = "CREATE TABLE student( ". "id INT NOT NULL AUTO_INCREMENT, ". "name CHAR(255) NOT NULL, ". "chinese INT(4) NOT NULL, ". "english INT(4) NOT NULL, ". "math INT(4) NOT NULL, ". "PRIMARY KEY ( id )); "; $retval = mysql_query( $sql_table, $conn ); if(! $retval ){ echo '数据表创建失败: ' . mysql_error()."
"; }else{ echo "数据表创建成功
"; } mysql_query('set names utf8'); mysql_close($conn);//关闭连接 ?>

Now you can see the new database studentinfo and data table student

in phpMyAdmin

Step 2: Add student information data (increase) in the student data table of the studentinfo database

Idea: Connect to the server->Connect to the database->Insert specified data into the data table

Note: Because the previous PHP has already created a server connection and connected to the database, the following code omits the connection establishment part and writes function statements directly.

function addtabel_data(){ //多维数组 $datas=array( array("name"=>"测试猫","chinese"=>100,"english"=>100,"math"=>100), array("name"=>"测试狗","chinese"=>99,"english"=>99,"math"=>99), array("name"=>"测试虎","chinese"=>98,"english"=>98,"math"=>98) ); for($i=0;$i0){ echo "添加数据成功
"; }else{ echo "添加数据失败
"; } } addtabel_data();//调用

When running php, I found that adding data failed. Why? Because a string with Chinese characters is passed in the name, and the name sorting rule defined in the student table is not utf-8? ? ?

It’s okay. We can modify the sorting rules with one click. After modifying it ourselves

, run it again. The data is added successfully and It is found that there is data in the table

Step 3: Query one or more specified pieces of information in the student table of the studentinfo database according to the query conditions (check)

Idea: Connect to the server -> Connect to the database -> Query the data table data according to the conditions

function selecttable_data($name){ $res=mysql_query("select * from student where name='$name'");//根据name来查询student数据 // $res=mysql_query("select * from student where name='$name' and chinese='$chinese'");//多条件查询连接符and // $res=mysql_query("select * from student");//查询student表里所有数据 // $res=mysql_query("select * from student limit 0,2“);//限制前面第1到2条数据 if($res&&mysql_num_rows($res)){ while($sql=mysql_fetch_assoc($res)){ $arr[]=$sql; } echo json_encode($arr,JSON_UNESCAPED_UNICODE);//把数据(数组嵌套json类型)转换为字符串输出，这个ajax拿数据经常用 }else{ echo "找不到该数据
"; } } selecttable_data("测试猫");//查询name为测试猫

Step 4: According to the modification conditions, the student in the studentinfo database Modify the specified data in the table (change)

Idea: Connect to the server->Connect to the database->Modify the specified data in the data table according to the conditions

function updatetabel_data($name,$chinese){ mysql_query("update student set chinese='$chinese' where name='$name'");//修改student表里为$name的chinese数据修改为$chinese $res=mysql_affected_rows();//返回影响行 if($res>0){ echo "修改成功
"; }else{ echo "修改失败
"; } } updatetabel_data("测试虎",90);//把测试虎的语文成绩修改为90分

Test Tiger Chinese score has changed from 98 Modify to 90

Step 5: Delete the specified data in the student table of the studentinfo database according to the deletion conditions (delete)

Idea: Connection Server—>Connect to the database—>Delete the specified data in the data table based on conditions

function deletetable_data($name){ mysql_query("delete from student where name='$name'");//删除student表里为$name的整条数据 $res=mysql_affected_rows();//返回影响行 if($res>0){ echo "删除成功
"; }else{ echo "删除失败
"; } } deletetable_data('测试虎');//删除name为测试虎这条数据

##Test Tiger This data has been deleted