## 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!
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！
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