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Detailed explanation of PHP7 database connection and addition, deletion, query and modification (mysqli method)

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Release: 2023-02-17 18:00:02
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## 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;





mysqli方法实现连接数据库,及增删查改

"; } else{ echo "数据库连接失败!
"; } $sql="CREATE DATABASE test"; if (mysqli_query($con,$sql)){ echo "数据库创建成功!
"; }else{ echo "数据库创建失败!
".mysqli_error($con)."
"; } 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,$table)){ echo "数据表创建成功!
"; } else{ echo "数据表创建失败!
".mysqli_error($con)."
"; } $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!
"; $result=$mysqli->query($query); foreach($result as $row){ echo $row["student_id"].'  '; echo $row["student_no"].'  '; echo $row["student_name"]."
"; } } else{ echo "数据插入失败!
".mysqli_error($con)."
"; } 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!
"; $result=$mysqli->query($query); foreach($result as $row){ echo $row["student_id"].'  '; echo $row["student_no"].'  '; echo $row["student_name"]."
"; } } else{ echo "数据更新失败!
".mysqli_error($con)."
"; } 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!
"; $result=$mysqli->query($query); foreach($result as $row){ echo $row["student_id"].'  '; echo $row["student_no"].'  '; echo $row["student_name"]."
"; } } else{ echo "数据删除失败!
".mysqli_error($con)."
"; } mysqli_free_result($del); mysqli_close($con); ?>
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The final effect is as follows:


Detailed explanation of PHP7 database connection and addition, deletion, query and modification (mysqli method) 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;

mysqli方法实现连接数据库,及增删查改
"; } else{ echo "数据库连接失败!
"; } $sql="CREATE DATABASE test"; if (mysqli_query($con,$sql)){ echo "数据库创建成功!
"; }else{ echo "数据库创建失败!
".mysqli_error($con)."
"; } 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,$table)){ echo "数据表创建成功!
"; } else{ echo "数据表创建失败!
".mysqli_error($con)."
"; } $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!
"; $result=$mysqli->query($query); foreach($result as $row){ echo $row["student_id"].'  '; echo $row["student_no"].'  '; echo $row["student_name"]."
"; } } else{ echo "数据插入失败!
".mysqli_error($con)."
"; } 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!
"; $result=$mysqli->query($query); foreach($result as $row){ echo $row["student_id"].'  '; echo $row["student_no"].'  '; echo $row["student_name"]."
"; } } else{ echo "数据更新失败!
".mysqli_error($con)."
"; } 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!
"; $result=$mysqli->query($query); foreach($result as $row){ echo $row["student_id"].'  '; echo $row["student_no"].'  '; echo $row["student_name"]."
"; } } else{ echo "数据删除失败!
".mysqli_error($con)."
"; } mysqli_free_result($del); mysqli_close($con); ?>
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最终效果如下:
Detailed explanation of PHP7 database connection and addition, deletion, query and modification (mysqli method)
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,                 sqlconnect)

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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source:csdn.net
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