Examples to explain php data access, examples to explain php data

Examples to explain php data access, examples to explain php data_PHP tutorial

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Release： 2016-07-12 08:52:34

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Examples to explain php data access, examples to explain php data

The examples in this article share two php data access methods for you to compare and analyze The similarities and differences between the two methods are finally provided with a small exercise for everyone. The specific content is as follows

Method 1: Outdated, just for understanding

1. Create a connection (establish a channel)

$db=mysql_connect("localhost","root","123"); //The brackets are "server address", "username", "password"

2. Choose which database to operate

mysql_select_db("mydb","$db");

3. Write sql statement

$sql="select * from Info";

4. Execute sql statement

$result=mysql_query($sql); //query means query

5. Get data from the result set ($result)

$row=mysql_fetch_row($result);  //每执行一次读取一行数据

$row1=mysql_fentch_row($result);  //执行第二条数据

var_dump($row);

//读取全部数据用循环：

while($row=mysql_fetch_row($result))

{

　　var_dump($row);　　

}

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Method 2: Object-oriented

1. Create a connection object:

$db=new MySQLi("localhost","root","123","mydb") //The contents in brackets are "server address", "user name", "password", "database name" ”

2. Determine whether the connection is wrong:

2.1 mysqli_connect_error(); //Represents a connection error

2.2

if(mysqli_connect_erroe())

{

echo "Connection failed!";

exit(); //Exit the program

}

2.3 !mysqli_connect_error or die ("Connection failed!"); //The front of "or" means the connection is correct, and the back means the connection failed

3. Write sql statement:

$sql="select * from nation";

4. Execute sql statement: if the execution is successful, return the result set object, if the execution fails, return false

$result=$db->query($sql);

5. Read data from the result set and first determine whether there is data

if($result)

{

　　//返回一行数据的索引数组，每次执行返回一条数据

 　　var_dump($result->fetch_row()); 

　　while($row=$result->fetch_row)

　　{

　　　　var_dump($row);

　　}

　　//返回一行数据的关联数组，每次执行返回一条数据

　　var_dump($result->fetch_row()); 

　　//通过二维数组返回所有数据

　　var_dump($result->fetch_all());

　　//以对象的方式返回一行数据

　　var_dump($result->fetch_object());

}

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Exercise:

1. Display the nation table on the page in the form of a drop-down menu

$db=new MySQLi("localhost","root","","mydb");

!mysqli_connection_erroe() or die ("连接失败！");

$sql="select*from nation";

$result=$db->query($sql);

if($result)

{

　　$att=$result->fetch_all();

　　echo "<select>";

　　foreach ($att as $value)

　　{

　　　　echo "<option value='{$value[0]}'>{$value[1]}</option>";

　　}

　　echo "</select>";

}

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2. Check out the Info table and display it in table form

$db=new MySQLi("localhost","root","","mydb");

!mysqli_connecton_error() or die("连接失败！");

$sql="select * from info";

$result=$bd->query($sql);

if($result)

{

$att=$result->fetch_all();

echo "<table border='1' width='100%' cellpadding='0' cellspacing='0'>";

echo "<tr><td>代号</td><td>姓名</td><td>性别</td><td>民族</td><td>生日</td></tr>";

foreach ($att as $value)

{

 echo "<tr>

<td>{$value[0]}</td>

<td>{$value[1]}</td>

<td>{$value[2]}</td>

<td>{$value[3]}</td>

<td>{$value[4]}</td>

</tr>";

}

echo "</table>";

}

 

//也可以用for循环

if($result)
{
　　$arr=$result->fetch_all();
　　echo "<table border='1' width='100%' cellpadding='0' cellspacing='0'>";
　　echo "<tr><td>Code</td><td>Name</td><td>Sex</td><td>Nation</td><td>Birthday</td></tr>";
　　for($i=0;$i<count($arr);$i++)
　　{
　　　　echo "<tr>
　　　　<td>{$arr[$i][0]}</td>
　　　　<td>{$arr[$i][1]}</td>
　　　　<td>{$arr[$i][2]}</td>
　　　　<td>{$arr[$i][3]}</td>
　　　　<td>{$arr[$i][4]}</td> 
　　　　</tr>";
　　}
　　echo "</table>";
}

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The above is the entire content of this article. I hope it will be helpful to everyone in learning PHP programming.