search
HomeBackend DevelopmentPHP TutorialMysqli operates the database, mysqli operates the database_PHP tutorial

Mysqli operates the database, mysqli operates the database

Every time you use mysql_connect to connect to the database, you will be prompted:

<span>1</span> Deprecated: <span>mysql_connect</span>(): The <span>mysql</span> extension is deprecated and will be removed in the future: <span>use</span> mysqli or PDO instead in E:\wamp\www\myquote\includes\<span>mysql_connect</span>.php on line 5

As a man with high demands and perfection, I really can’t stand this reminder. You can't even hide from him - only by solving the little stone in his heart can it be broken

Then first learn to use Mysqli to operate the database:

1.  When interacting with a Mysql database, the connection must be established first and the connection must be disconnected last. This includes connecting to the server and selecting a database, and finally closing the connection. As with almost all features of MySQL, this can be accomplished using an object-oriented approach or a procedural approach.

1.1 Create a Mysqli object

<span>1</span> <?<span>php
</span><span>2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span>3</span> ?>

1.2 Host, user, password, database connected to Mysql

<span>1</span> <?<span>php
</span><span>2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span>3</span> <span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span>4</span> ?>

1.3 Create a Mysqli object for connection parameters

<span>1</span> <?<span>php
</span><span>2</span> <span>$mysqli</span>=<span>new</span> mysqli('localhost','root','admin','test');<span>//</span><span>实例化mysqli
</span><span>3</span> <span>//$mysqli->connect('localhost','root','admin','test');</span>
<span>4</span> ?>

1.4 Change the default connection database

<span>1</span> <?<span>php
</span><span>2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span>3</span> <span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span>4</span> <span>$mysqli</span>->select_db('abc');<span>//</span><span>更换连接默认的数据库为abc数据库</span>
<span>5</span> <span>$mysqli</span>->close();<span>//</span><span>别忘了关闭你的"小资源";</span>
<span>6</span> ?>

2Handling connection errors

2.1 If the MySQL database cannot be connected, it is unlikely that the page will continue to do its intended job, so be sure to monitor connection errors and react accordingly. The Mysqli extension contains many features that can be used to capture error information, such as the mysqli_connect_errno() and mysqli_connect_error() methods.

<span>1</span> <span>mysqli_connect_errno</span><span>()函数返回链接数据库返回的错误号。
</span><span>2</span> <span>mysqli_connect_error</span><span>()函数返回连接数据库返回的错误代码。</span>

How to use:

<span> 1</span> <?<span>php
</span><span> 2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span> 3</span> <span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span> 4</span> <span>if</span>(<span>mysqli_connect_error</span><span>()){
</span><span> 5</span>     <span>echo</span>'数据库连接错误,错误信息是.'.<span>mysqli_connect_error</span><span>();
</span><span> 6</span>     <span>exit</span><span>();
</span><span> 7</span> }<span>else</span><span>{
</span><span> 8</span>     <span>echo</span> '数据库连接成功'<span>;
</span><span> 9</span> <span>}
</span><span>10</span> <span>$mysqli</span>->close();<span>//</span><span>别忘了关闭你的"小资源";</span>
<span>11</span> ?>

A process-oriented method is used here to determine whether the database connection is successful. So why not use object-oriented method to judge? My understanding is that before judging whether the database connection is successful, you must first prove whether the object you want to instantiate is available. . Therefore, a process-oriented approach is used to judge. (If there is something wrong, you can discuss it together. I am also a scumbag in elementary school)

2.2 mysqli_error——Returns database operation error information. mysqli_errno——Return database operation error code

<span> 1</span> <?<span>php
</span><span> 2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span> 3</span> <span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span> 4</span> <span>if</span>(<span>mysqli_connect_error</span><span>()){
</span><span> 5</span>     <span>echo</span>'数据库连接错误,错误信息是.'.<span>mysqli_connect_error</span><span>();
</span><span> 6</span>     <span>exit</span><span>();
</span><span> 7</span> }<span>else</span><span>{
</span><span> 8</span>     <span>echo</span> '数据库连接成功<br/>'<span>;
</span><span> 9</span> <span>}
</span><span>10</span> <span>if</span> (!<span>$mysqli</span>->query("SET a=1")) {<span>//</span><span>$mysqli->query()执行sql语句</span>
<span>11</span>     <span>echo</span> "错误信息是: ".<span>$mysqli</span>->error.'<br/>'<span>;
</span><span>12</span>     <span>echo</span> "错误代码是: ".<span>$mysqli</span>-><span>errno;
</span><span>13</span> <span>}
</span><span>14</span> <span>$mysqli</span>->close();<span>//</span><span>别忘了关闭你的"小资源";</span>
<span>15</span> ?>

Output:

Database connection successful
The error message is: Unknown system variable 'a'
The error code is: 1193

3 Interact with the database.

① The vast majority of queries are related to creation (Creation), retrieval (Retrieval), update (Update) and deletion (Deletion) tasks. These tasks are collectively called CRUD.

② Obtaining data Most of the work of web page programs is to obtain and format the requested data. To do this, you need to send a SELECT query to the database, then iteratively process the results, output each row to the browser, and output it according to your own requirements.

<span> 1</span> <?<span>php
</span><span> 2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span> 3</span> <span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span> 4</span> <span>if</span>(<span>mysqli_connect_error</span><span>()){
</span><span> 5</span>     <span>exit</span>('数据库连接错误,错误信息是.'.<span>mysqli_connect_error</span><span>());
</span><span> 6</span> <span>}
</span><span> 7</span> <span>$mysqli</span>->set_charset("UTF8");<span>//</span><span>设置数据库编码</span>
<span> 8</span> <span>$sql</span>='select * from user';<span>//</span><span>创建一句SQL语句</span>
<span> 9</span> <span>$result</span>=<span>$mysqli</span>->query(<span>$sql</span>);<span>//</span><span>执行sql语句把结果集赋给$result</span>
<span>10</span> <span>print_r</span>(<span>$result</span>->fetch_row());<span>//</span><span>将结果集的第一行输出</span>
<span>11</span> <span>$result</span>->free();<span>//</span><span>释放查询内存(销毁)</span>
<span>12</span> <span>$mysqli</span>->close();<span>//</span><span>别忘了关闭你的"小资源";</span>
<span>13</span> ?>

Output:

Array ( [0] => 1 [1] => Akita Jia [2] => 123456 )

3.1 Parsing query results

Once the query has been executed and the result set has been prepared, it is time to parse the resulting rows. You can use multiple methods to get the fields in each row. Which method you choose mainly comes down to personal preference, because only the method of referencing the fields differs.

3.1.1 Put the result set into an object. Since you may use the object-oriented syntax of mysqli, you can completely manage the results in an object-oriented way. Fruit set.

This can be done using the fetch_object() method.

<span> 1</span> <?<span>php
</span><span> 2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span> 3</span> <span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span> 4</span> <span>if</span>(<span>mysqli_connect_error</span><span>()){
</span><span> 5</span>     <span>exit</span>('数据库连接错误,错误信息是.'.<span>mysqli_connect_error</span><span>());
</span><span> 6</span> <span>}
</span><span> 7</span> <span>$mysqli</span>->set_charset("UTF8");<span>//</span><span>设置数据库编码</span>
<span> 8</span> <span>$sql</span>='select * from user';<span>//</span><span>创建一句SQL语句</span>
<span> 9</span> <span>$result</span>=<span>$mysqli</span>->query(<span>$sql</span>);<span>//</span><span>执行sql语句把结果集赋给$result</span>
<span>10</span> <span>/*</span>
<span>11</span> <span>$row = $result->fetch_object();//将结果集包装成对象
</span><span>12</span> <span>echo $row->user;//输出对象中的一个字段(属性)
</span><span>13</span> <span>*/</span>
<span>14</span> <span>while</span> (!!<span>$row</span> = <span>$result</span>->fetch_object()){<span>//</span><span>//遍历所有的用户名称</span>
<span>15</span> <span>echo</span> <span>$row</span>->user."<br>"<span>;
</span><span>16</span> <span>var_dump</span>(<span>$row</span><span>);
</span><span>17</span> <span>}
</span><span>18</span> <span>$result</span>->free();<span>//</span><span>释放查询内存(销毁)</span>
<span>19</span> <span>$mysqli</span>->close();<span>//</span><span>别忘了关闭你的"小资源";</span>
<span>20</span> ?>

Output:

Akita Kazuo

object(stdClass)#3 (3) { ["id"]=> string(1) "1" ["user"]=> string(9) "Akita Ka" ["psw"]= > string(6) "123456" }
Andy Lau

object(stdClass)#4 (3) { ["id"]=> string(1) "2" ["user"]=> string(9) "Andy Lau" ["psw"]=> ; string(6) "654321" }

3.1.2 Using indexed arrays and associative arrays fetch_array();

<span> 1</span> <?<span>php
</span><span> 2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span> 3</span> <span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span> 4</span> <span>if</span>(<span>mysqli_connect_error</span><span>()){
</span><span> 5</span>     <span>exit</span>('数据库连接错误,错误信息是.'.<span>mysqli_connect_error</span><span>());
</span><span> 6</span> <span>}
</span><span> 7</span> <span>$mysqli</span>->set_charset("UTF8");<span>//</span><span>设置数据库编码</span>
<span> 8</span> <span>$sql</span>='select * from user';<span>//</span><span>创建一句SQL语句</span>
<span> 9</span> <span>$result</span>=<span>$mysqli</span>->query(<span>$sql</span>);<span>//</span><span>执行sql语句把结果集赋给$result</span>
<span>10</span> 
<span>11</span> <span>$row</span> = <span>$result</span>->fetch_array();<span>//</span><span>将结果集包装成数组(索引+关联)</span>
<span>12</span> <span>echo</span> <span>$row</span>[1].'<br/>';<span>//</span><span>输出下标是1的字段(属性)</span>
<span>13</span> <span>var_dump</span>(<span>$row</span><span>);
</span><span>14</span> <span>/*</span>
<span>15</span> <span>while (!!$row = $result->fetch_array()){//遍历全部
</span><span>16</span> <span>echo $row[1]."<br/>";
</span><span>17</span> <span>}</span><span>*/</span>
<span>18</span> 
<span>19</span> <span>$result</span>->free();<span>//</span><span>释放查询内存(销毁)</span>
<span>20</span> <span>$mysqli</span>->close();<span>//</span><span>别忘了关闭你的"小资源";</span>
<span>21</span> ?>

Output:

Akita Yoshi
array(6) { [0]=> string(1) "1" ["id"]=> string(1) "1" [1]=> string(9 ) "Akita Ka" ["user"]=> string(9) "Akita Ka" [2]=> string(6) "123456" ["psw"]=> string(6) "123456" }

3.1.3 Using index array fetch_row();

<span> 1</span> <?<span>php
</span><span> 2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span> 3</span> <span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span> 4</span> <span>if</span>(<span>mysqli_connect_error</span><span>()){
</span><span> 5</span>     <span>exit</span>('数据库连接错误,错误信息是.'.<span>mysqli_connect_error</span><span>());
</span><span> 6</span> <span>}
</span><span> 7</span> <span>$mysqli</span>->set_charset("UTF8");<span>//</span><span>设置数据库编码</span>
<span> 8</span> <span>$sql</span>='select * from user';<span>//</span><span>创建一句SQL语句</span>
<span> 9</span> <span>$result</span>=<span>$mysqli</span>->query(<span>$sql</span>);<span>//</span><span>执行sql语句把结果集赋给$result</span>
<span>10</span> <span>$row</span> = <span>$result</span>->fetch_row();<span>//</span><span>将结果集包装成索引数组</span>
<span>11</span> <span>echo</span> <span>$row</span>[2<span>];
</span><span>12</span> <span>$result</span>->free();<span>//</span><span>释放查询内存(销毁)</span>
<span>13</span> <span>$mysqli</span>->close();<span>//</span><span>别忘了关闭你的"小资源";</span>
<span>14</span> ?>

Output:

123456

3.1.4 Using associative arrays fetch_assoc();

<span> 1</span> <?<span>php
</span><span> 2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span> 3</span> <span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span> 4</span> <span>if</span>(<span>mysqli_connect_error</span><span>()){
</span><span> 5</span>     <span>exit</span>('数据库连接错误,错误信息是.'.<span>mysqli_connect_error</span><span>());
</span><span> 6</span> <span>}
</span><span> 7</span> <span>$mysqli</span>->set_charset("UTF8");<span>//</span><span>设置数据库编码</span>
<span> 8</span> <span>$sql</span>='select * from user';<span>//</span><span>创建一句SQL语句</span>
<span> 9</span> <span>$result</span>=<span>$mysqli</span>->query(<span>$sql</span>);<span>//</span><span>执行sql语句把结果集赋给$result</span>
<span>10</span> <span>$row</span> = <span>$result</span>->fetch_assoc();<span>//</span><span>将结果集包装成关联数组</span>
<span>11</span> <span>echo</span> <span>$row</span>['psw'<span>];
</span><span>12</span> <span>$result</span>->free();<span>//</span><span>释放查询内存(销毁)</span>
<span>13</span> <span>$mysqli</span>->close();<span>//</span><span>别忘了关闭你的"小资源";</span>
<span>14</span> ?>

Output:

123456

4 Determine the selected rows and affected rows

Usually you want to be able to determine the number of rows returned by the SELECT query, or be affected by INSERT, UPDATE or DELET queries the number of rows affected by .

We can use the num_rows and affected_rows two attributes

<span> 1</span> <?<span>php
</span><span> 2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span> 3</span> <span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span> 4</span> <span>if</span>(<span>mysqli_connect_error</span><span>()){
</span><span> 5</span>     <span>exit</span>('数据库连接错误,错误信息是.'.<span>mysqli_connect_error</span><span>());
</span><span> 6</span> <span>}
</span><span> 7</span> <span>$mysqli</span>->set_charset("UTF8");<span>//</span><span>设置数据库编码</span>
<span> 8</span> <span>$sql</span>='select * from user';<span>//</span><span>创建一句SQL语句</span>
<span> 9</span> <span>$result</span>=<span>$mysqli</span>->query(<span>$sql</span>);<span>//</span><span>执行sql语句把结果集赋给$result</span>
<span>10</span> <span>echo</span> <span>$result</span>->num_rows;<span>//</span><span>当使用查询时,想了解SELECT查询了多少行,可以使用num_rows。</span>
<span>11</span> <span>echo</span>"<br/>"<span>;
</span><span>12</span> <span>echo</span> <span>$mysqli</span>->affected_rows;<span>//</span><span>当使用查询时,想了解SELECT、INSERT、UPDATE、DELETE查询时影响的行数,可以使用affected_rows;注意,它是$mysqli下的属性</span>
<span>13</span> <span>$result</span>->free();<span>//</span><span>释放查询内存(销毁)</span>
<span>14</span> <span>$mysqli</span>->close();<span>//</span><span>别忘了关闭你的"小资源";</span>
<span>15</span> ?>

Output:

2
2

5  移动指针的操作和获取字段

  当你并不想从第一条数据开始获取,或者并不想从第一个字段获取,你可以使用数据指针移动或者字段指针移动的方式调整到恰当的位置。当然,你还可以获取字段的名称及其相关的属性

  

<span> 1</span> <?<span>php
</span><span> 2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span> 3</span> <span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span> 4</span> <span>if</span>(<span>mysqli_connect_error</span><span>()){
</span><span> 5</span>     <span>exit</span>('数据库连接错误,错误信息是.'.<span>mysqli_connect_error</span><span>());
</span><span> 6</span> <span>}
</span><span> 7</span> <span>$mysqli</span>->set_charset("UTF8");<span>//</span><span>设置数据库编码</span>
<span> 8</span> <span>$sql</span>='select * from user';<span>//</span><span>创建一句SQL语句</span>
<span> 9</span> <span>$result</span>=<span>$mysqli</span>->query(<span>$sql</span>);<span>//</span><span>执行sql语句把结果集赋给$result</span>
<span>10</span> <span>echo</span> <span>$result</span>->field_count;<span>//</span><span>计算有多少条字段</span>
<span>11</span> <span>echo</span>"<br/>";<span>//</span><span>输出 3</span>
<span>12</span> <span>$field</span> = <span>$result</span>->fetch_field();<span>//</span><span>获取字段的名称</span>
<span>13</span> <span>echo</span> <span>$field</span>->name;<span>//</span><span>输出id</span>
<span>14</span> <span>echo</span> '<br/>'<span>;
</span><span>15</span> <span>while</span> (!!<span>$field</span> = <span>$result</span>->fetch_field()) {<span>//</span><span>遍历字段</span>
<span>16</span> <span>echo</span> <span>$field</span>->name.'<br />'<span>;
</span><span>17</span> <span>}
</span><span>18</span> <span>$result</span>->free();<span>//</span><span>释放查询内存(销毁)</span>
<span>19</span> <span>$mysqli</span>->close();<span>//</span><span>别忘了关闭你的"小资源";</span>
<span>20</span> ?>

 

 

输出:

3
id
user
psw

5.1

<?<span>php
</span><span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span>if</span>(<span>mysqli_connect_error</span><span>()){
    </span><span>exit</span>('数据库连接错误,错误信息是.'.<span>mysqli_connect_error</span><span>());
}
</span><span>$mysqli</span>->set_charset("UTF8");<span>//</span><span>设置数据库编码</span>
<span>$sql</span>='select * from user';<span>//</span><span>创建一句SQL语句</span>
<span>$result</span>=<span>$mysqli</span>->query(<span>$sql</span>);<span>//</span><span>执行sql语句把结果集赋给$result</span>
<span>print_r</span>(<span>$result</span>->fetch_fields());<span>//</span><span>一次性取得字段数组</span>
<span>$result</span>->free();<span>//</span><span>释放查询内存(销毁)</span>
<span>$mysqli</span>->close();<span>//</span><span>别忘了关闭你的"小资源";</span>
?>

 

 

输出:

<span> 1</span> <span>Array</span>
<span> 2</span> <span>(
</span><span> 3</span>     [0] => stdClass <span>Object</span>
<span> 4</span> <span>        (
</span><span> 5</span>             [name] =><span> id
</span><span> 6</span>             [orgname] =><span> id
</span><span> 7</span>             [table] =><span> user
</span><span> 8</span>             [orgtable] =><span> user
</span><span> 9</span>             [def] => 
<span>10</span>             [db] =><span> test
</span><span>11</span>             [catalog] =><span> def
</span><span>12</span>             [max_length] => 1
<span>13</span>             [length] => 11
<span>14</span>             [charsetnr] => 63
<span>15</span>             [flags] => 49667
<span>16</span>             [type] => 3
<span>17</span>             [decimals] => 0
<span>18</span> <span>        )
</span><span>19</span> 
<span>20</span>     [1] => stdClass <span>Object</span>
<span>21</span> <span>        (
</span><span>22</span>             [name] =><span> user
</span><span>23</span>             [orgname] =><span> user
</span><span>24</span>             [table] =><span> user
</span><span>25</span>             [orgtable] =><span> user
</span><span>26</span>             [def] => 
<span>27</span>             [db] =><span> test
</span><span>28</span>             [catalog] =><span> def
</span><span>29</span>             [max_length] => 9
<span>30</span>             [length] => 765
<span>31</span>             [charsetnr] => 33
<span>32</span>             [flags] => 4097
<span>33</span>             [type] => 253
<span>34</span>             [decimals] => 0
<span>35</span> <span>        )
</span><span>36</span> 
<span>37</span>     [2] => stdClass <span>Object</span>
<span>38</span> <span>        (
</span><span>39</span>             [name] =><span> psw
</span><span>40</span>             [orgname] =><span> psw
</span><span>41</span>             [table] =><span> user
</span><span>42</span>             [orgtable] =><span> user
</span><span>43</span>             [def] => 
<span>44</span>             [db] =><span> test
</span><span>45</span>             [catalog] =><span> def
</span><span>46</span>             [max_length] => 6
<span>47</span>             [length] => 765
<span>48</span>             [charsetnr] => 33
<span>49</span>             [flags] => 4097
<span>50</span>             [type] => 253
<span>51</span>             [decimals] => 0
<span>52</span> <span>        )
</span><span>53</span> 
<span>54</span> )

 

5.2  

<span>1</span> <span>$result</span>->data_seek(1);<span>//</span><span>移动数据指针</span>
<span>2</span> <span>$result</span>->field_seek(1);<span>//</span><span>移动字段指针</span>

 

 6  执行多条SQL语句

  有的时候,我们需要在一张页面上同时执行多条SQL语句,之前的方法就是分别创建多个结果集然后使用。但这样资源消耗很大,也不利于管理。 PHP提供了执行多条SQL语句的方法$mysqli->multi_query();

<span> 1</span> <?<span>php
</span><span> 2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span> 3</span> <span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span> 4</span> <span>if</span>(<span>mysqli_connect_error</span><span>()){
</span><span> 5</span>     <span>exit</span>('数据库连接错误,错误信息是.'.<span>mysqli_connect_error</span><span>());
</span><span> 6</span> <span>}
</span><span> 7</span> <span>$mysqli</span>->set_charset("UTF8");<span>//</span><span>设置数据库编码
</span><span> 8</span> <span>//创建多条SQL语句</span>
<span> 9</span> <span>$sql</span> .= "SELECT * FROM user;"<span>;
</span><span>10</span> <span>$sql</span> .= "SELECT * FROM photo;"<span>;
</span><span>11</span> <span>$sql</span> .= "SELECT * FROM article"<span>;
</span><span>12</span> <span>if</span> (<span>$mysqli</span>->multi_query(<span>$sql</span>)) {<span>//</span><span>开始执行多条SQL语句</span>
<span>13</span> <span>$result</span> = <span>$mysqli</span>-><span>store_result();
</span><span>14</span> <span>print_r</span>(<span>$result</span>->fetch_array());<span>//</span><span>开始获取第一条SQL语句的结果集</span>
<span>15</span> <span>$mysqli</span>->next_result();<span>//</span><span>将结果集指针移到下一个</span>
<span>16</span> <span>$result</span> = <span>$mysqli</span>-><span>store_result();
</span><span>17</span> <span>print_r</span>(<span>$result</span>-><span>fetch_array());
</span><span>18</span> <span>$mysqli</span>-><span>next_result();
</span><span>19</span> <span>$result</span> = <span>$mysqli</span>-><span>store_result();
</span><span>20</span> <span>print_r</span>(<span>$result</span>-><span>fetch_array());
</span><span>21</span> } <span>else</span><span> {
</span><span>22</span> <span>echo</span> 'sql语句有误!'<span>;
</span><span>23</span> <span>}
</span><span>24</span> <span>$result</span>->free();<span>//</span><span>释放查询内存(销毁)</span>
<span>25</span> <span>$mysqli</span>->close();<span>//</span><span>别忘了关闭你的"小资源";</span>
<span>26</span> ?>

 

7  执行数据库事务

事务(transaction)是作为整个一个单元的一组有序的数据库操作。如果一组中的所有操作都成功,则认为事务成功,即使只有一个失败操作,事务也不成功。如果所有操作成功完成,事务则提交(commit),其修改将作用于所有其他数据库进程。如果一个操作失败,则事务将回滚(roll back),该事务所有操作的影响都将取消。首先,您的MySQL是InnoDB或BDB引擎的一种,一般来说,你安装了AppServ的集成包,你选择InnoDB的引擎的数据库即可。如果你建立的表不是InnoDB,可以在phpmyadmin里修改

<span> 1</span> <?<span>php
</span><span> 2</span> <span>$mysqli</span>=<span>new</span> mysqli();<span>//</span><span>实例化mysqli</span>
<span> 3</span> <span>$mysqli</span>->connect('localhost','root','admin','test'<span>);
</span><span> 4</span> <span>if</span>(<span>mysqli_connect_error</span><span>()){
</span><span> 5</span>     <span>exit</span>('数据库连接错误,错误信息是.'.<span>mysqli_connect_error</span><span>());
</span><span> 6</span> <span>}
</span><span> 7</span> <span>$mysqli</span>->set_charset("UTF8");<span>//</span><span>设置数据库编码
</span><span> 8</span> <span>//首先你必须关闭自动提交数据</span>
<span> 9</span> <span>$mysqli</span>->autocommit(<span>false</span><span>);
</span><span>10</span> <span>//</span><span>创建一个SQL语句,必须同时运行成功,不能出现一个成功,一个失败</span>
<span>11</span> <span>$sql</span> .= "UPDATE `friend` SET state=state+5 WHERE id=1;"<span>;
</span><span>12</span> <span>$sql</span> .= "UPDATE `flower` SET tg_flower=flower-5 WHERE id=1;"<span>;
</span><span>13</span> <span>//</span><span>执行两条SQL语句</span>
<span>14</span> <span>if</span> (<span>$mysqli</span>->multi_query(<span>$sql</span><span>)) {
</span><span>15</span> <span>//</span><span>获取第一条SQL一影响的行数</span>
<span>16</span> <span>$success</span> = <span>$mysqli</span>->affected_rows == 1 ? <span>true</span> : <span>false</span><span>;
</span><span>17</span> <span>//</span><span>下移,第二条SQL</span>
<span>18</span> <span>$mysqli</span>-><span>next_result();
</span><span>19</span> <span>//</span><span>获取第二条SQL影响的行数</span>
<span>20</span> <span>$success2</span> = <span>$mysqli</span>->affected_rows == 1 ? <span>true</span> : <span>false</span><span>;
</span><span>21</span> <span>//</span><span>判断是否都正常通过了,两个SQL</span>
<span>22</span> <span>if</span> (<span>$success</span> && <span>$success2</span><span>) {
</span><span>23</span> <span>$mysqli</span>-><span>commit();
</span><span>24</span> <span>echo</span> '完美提交!'<span>;
</span><span>25</span> } <span>else</span><span> {
</span><span>26</span> <span>$mysqli</span>-><span>rollback();
</span><span>27</span> <span>echo</span> '程序出现异常!'<span>;}
</span><span>28</span> } <span>else</span><span> {
</span><span>29</span> <span>echo</span> "SQL语句有误:".<span>$mysqli</span>->errno.<span>$mysqli</span>-><span>error;
</span><span>30</span> <span>}
</span><span>31</span> <span>//</span><span>最后还必须开启自动提交</span>
<span>32</span> <span>$mysqli</span>->autocommit(<span>true</span><span>);
</span><span>33</span> <span>$result</span>->free();<span>//</span><span>释放查询内存(销毁)</span>
<span>34</span> <span>$mysqli</span>->close();<span>//</span><span>别忘了关闭你的"小资源";</span>
<span>35</span> ?>

 

www.bkjia.comtruehttp://www.bkjia.com/PHPjc/1133578.htmlTechArticleMysqli 操作数据库,mysqli操作数据库 每次用到mysql_connect连接数据库的时候都会提示: 1 Deprecated: mysql_connect (): The mysql extension is deprecated an...
Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
PHP and Python: Different Paradigms ExplainedPHP and Python: Different Paradigms ExplainedApr 18, 2025 am 12:26 AM

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP and Python: A Deep Dive into Their HistoryPHP and Python: A Deep Dive into Their HistoryApr 18, 2025 am 12:25 AM

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

Choosing Between PHP and Python: A GuideChoosing Between PHP and Python: A GuideApr 18, 2025 am 12:24 AM

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP and Frameworks: Modernizing the LanguagePHP and Frameworks: Modernizing the LanguageApr 18, 2025 am 12:14 AM

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHP's Impact: Web Development and BeyondPHP's Impact: Web Development and BeyondApr 18, 2025 am 12:10 AM

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

How does PHP type hinting work, including scalar types, return types, union types, and nullable types?How does PHP type hinting work, including scalar types, return types, union types, and nullable types?Apr 17, 2025 am 12:25 AM

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values ​​and handle functions that may return null values.

How does PHP handle object cloning (clone keyword) and the __clone magic method?How does PHP handle object cloning (clone keyword) and the __clone magic method?Apr 17, 2025 am 12:24 AM

In PHP, use the clone keyword to create a copy of the object and customize the cloning behavior through the \_\_clone magic method. 1. Use the clone keyword to make a shallow copy, cloning the object's properties but not the object's properties. 2. The \_\_clone method can deeply copy nested objects to avoid shallow copying problems. 3. Pay attention to avoid circular references and performance problems in cloning, and optimize cloning operations to improve efficiency.

PHP vs. Python: Use Cases and ApplicationsPHP vs. Python: Use Cases and ApplicationsApr 17, 2025 am 12:23 AM

PHP is suitable for web development and content management systems, and Python is suitable for data science, machine learning and automation scripts. 1.PHP performs well in building fast and scalable websites and applications and is commonly used in CMS such as WordPress. 2. Python has performed outstandingly in the fields of data science and machine learning, with rich libraries such as NumPy and TensorFlow.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
1 months agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. Best Graphic Settings
1 months agoBy尊渡假赌尊渡假赌尊渡假赌
Will R.E.P.O. Have Crossplay?
1 months agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Safe Exam Browser

Safe Exam Browser

Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

WebStorm Mac version

WebStorm Mac version

Useful JavaScript development tools

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

Integrate Eclipse with SAP NetWeaver application server.

MinGW - Minimalist GNU for Windows

MinGW - Minimalist GNU for Windows

This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

Atom editor mac version download

Atom editor mac version download

The most popular open source editor