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Detailed explanation of PHP7 database connection and addition, deletion, query and modification (mysqli method)
Detailed explanation of PHP7 database connection and addition, deletion, query and modification (mysqli method)
## Use the mysqli method to achieve the following functions (php7):
1. Connect to the MySQL database server; 2. Create a database named test;
3. Create a data table named "testTable" in the database. The data table contains at least three fields. Field names, types and attributes are customized;
4. Insert three records into the database and query all data in the data table;
5. Modify one of the records and query all data in the data table;
6. Delete one of the records and query all the data in the data table;
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" >
<title>mysqli方法实现连接数据库，及增删查改</title>
</head>
<body>
<?php
$con = @mysqli_connect("localhost","root","15118595615");
if($con){
echo "数据库连接成功！</br>";
}
else{
echo "数据库连接失败！</br>";
}
$sql="CREATE DATABASE test";
if (mysqli_query($con,$sql)){
echo "数据库创建成功!</br>";
}else{
echo "数据库创建失败!</br>".mysqli_error($con)."</br>";
}
mysqli_select_db($con,"test");
$table="CREATE TABLE testTable(
student_id int(11) auto_increment primary key,
student_no char(10) not null unique,
student_name char(20) not null)";
if(mysqli_query($con,$table)){
echo "数据表创建成功!</br>";
}
else{
echo "数据表创建失败!</br>".mysqli_error($con)."</br>";
}
$mysqli=new mysqli("localhost","root","15118595615","test");
$query="select * from testTable";
$insertdatas=mysqli_query($con,"insert into testTable(student_id,student_no,student_name) values('null','20170001','张三')");
mysqli_free_result($insertdatas);
$insertdatas=mysqli_query($con,"insert into testTable(student_id,student_no,student_name) values('null','20170002','李四')");
mysqli_free_result($insertdatas);
$insertdatas=mysqli_query($con,"insert into testTable(student_id,student_no,student_name) values('null','20170003','王五')");
if($insertdatas){
echo "数据插入成功！</br>";
$result=$mysqli->query($query);
foreach($result as $row){
echo $row["student_id"].'  ';
echo $row["student_no"].'  ';
echo $row["student_name"]."</br>";
}
}
else{
echo "数据插入失败！</br>".mysqli_error($con)."</br>";
}
mysqli_free_result($insertdatas);
$up=mysqli_query($con,"update testTable set student_no='20180001' where student_name='张三'");
if($up){
echo "数据更新成功!</br>";
$result=$mysqli->query($query);
foreach($result as $row){
echo $row["student_id"].'  ';
echo $row["student_no"].'  ';
echo $row["student_name"]."</br>";
}
}
else{
echo "数据更新失败!</br>".mysqli_error($con)."</br>";
}
mysqli_free_result($up);
$del=mysqli_query($con,"delete from testTable where student_name='李四'");
if($del){
echo "数据删除成功!</br>";
$result=$mysqli->query($query);
foreach($result as $row){
echo $row["student_id"].'  ';
echo $row["student_no"].'  ';
echo $row["student_name"]."</br>";
}
}
else{
echo "数据删除失败!</br>".mysqli_error($con)."</br>";
}
mysqli_free_result($del);
mysqli_close($con);
?>
</body>
</html>
When writing code Pay attention to some differences between PHP7 and PHP5:
1. PHP7 needs to replace PHP5’s
mysql() with mysqli(); 2. PHP7’s query statement must Written as
mysqli(
c
o
n
n
e
c
t
, ,
Connect,
connect,sql), the writing method of PHP5 is opposite to that of PHP7mysql(
s
q q
l
,
sql,
sql,connect）；
Warm reminder: Be sure to use the mysqli_free_result() function to release resources after each query! Otherwise, an error will be reported and the next query statement cannot be executed! I took a lot of detours when I was a beginner, and I have learned hard lessons. I hope it can help my beginner friends to avoid detours!
用mysqli方法 实现以下功能（php7）：
1、连接MySQL数据库服务器；
2、创建一个名为test的数据库；
3、在该数据库内创建一个名为“testTable”的数据表，数据表至少包含三个字段，字段名字、类型和属性自定；
4、为该数据库插入三条记录，并查询该数据表的所有数据；
5、修改其中的一条记录，并查询该数据表的所有数据；
6、删除其中的一条记录，并查询该数据表的所有数据；
<!DOCTYPE html><html><head><meta charset="UTF-8" ><title>mysqli方法实现连接数据库，及增删查改</title></head><body><?php
$con = @mysqli_connect("localhost","root","15118595615");
if($con){
echo "数据库连接成功！</br>";
}
else{
echo "数据库连接失败！</br>";
}
$sql="CREATE DATABASE test";
if (mysqli_query($con,$sql)){
echo "数据库创建成功!</br>";
}else{
echo "数据库创建失败!</br>".mysqli_error($con)."</br>";
}
mysqli_select_db($con,"test");
$table="CREATE TABLE testTable(
student_id int(11) auto_increment primary key,
student_no char(10) not null unique,
student_name char(20) not null)";
if(mysqli_query($con,$table)){
echo "数据表创建成功!</br>";
}
else{
echo "数据表创建失败!</br>".mysqli_error($con)."</br>";
}
$mysqli=new mysqli("localhost","root","15118595615","test");
$query="select * from testTable";
$insertdatas=mysqli_query($con,"insert into testTable(student_id,student_no,student_name) values('null','20170001','张三')");
mysqli_free_result($insertdatas);
$insertdatas=mysqli_query($con,"insert into testTable(student_id,student_no,student_name) values('null','20170002','李四')");
mysqli_free_result($insertdatas);
$insertdatas=mysqli_query($con,"insert into testTable(student_id,student_no,student_name) values('null','20170003','王五')");
if($insertdatas){
echo "数据插入成功！</br>";
$result=$mysqli->query($query);
foreach($result as $row){
echo $row["student_id"].'  ';
echo $row["student_no"].'  ';
echo $row["student_name"]."</br>";
}
}
else{
echo "数据插入失败！</br>".mysqli_error($con)."</br>";
}
mysqli_free_result($insertdatas);
$up=mysqli_query($con,"update testTable set student_no='20180001' where student_name='张三'");
if($up){
echo "数据更新成功!</br>";
$result=$mysqli->query($query);
foreach($result as $row){
echo $row["student_id"].'  ';
echo $row["student_no"].'  ';
echo $row["student_name"]."</br>";
}
}
else{
echo "数据更新失败!</br>".mysqli_error($con)."</br>";
}
mysqli_free_result($up);
$del=mysqli_query($con,"delete from testTable where student_name='李四'");
if($del){
echo "数据删除成功!</br>";
$result=$mysqli->query($query);
foreach($result as $row){
echo $row["student_id"].'  ';
echo $row["student_no"].'  ';
echo $row["student_name"]."</br>";
}
}
else{
echo "数据删除失败!</br>".mysqli_error($con)."</br>";
}
mysqli_free_result($del);
mysqli_close($con);
?></body></html>最终效果如下：
写代码的时候要注意PHP7和PHP5的一些差别：
1、PHP7要将PHP5的mysql（）换成mysqli（）；
2、PHP7的查询语句要写成mysqli（
c
o
n
n
e
c
t
,
connect,
connect,sql），PHP5的写法和PHP7的相反mysql（
s
q
l
，
sql，
sql，connect）；
温馨提示：
每次查询完之后一定要用mysqli_free_result（）函数释放资源！不然会报错，无法执行下一条查询语句！初学的时候走了不少弯路，血的教训，希望能给初学的朋友帮助，少走弯路！
The above is the detailed content of Detailed explanation of PHP7 database connection and addition, deletion, query and modification (mysqli method). For more information, please follow other related articles on the PHP Chinese website!
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