Examples of PHP data access, examples of PHP data _php tutorial

Examples of PHP data access, examples of PHP data to explain

The example of this article for you to share two ways to access PHP data , we can compare, analyze the similarities and differences between the two ways, and finally provide a small exercise, the specific content as follows

Way One: obsolete, only do understand

1. Making a connection (establishing a channel)

$db =mysql_connect ("localhost", "root", "123"); In parentheses are "server address", "User name", "Password"

2. Select which database to operate

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

3. Write SQL statements

$sql = "SELECT * from Info";

4. Execute SQL statements

$result =mysql_query ($sql); Query has the meaning of inquiry

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

$row =mysql_fetch_row ($result);  Reads one row of data $row1=mysql_fentch_row ($result) per execution;  Executes the second data var_dump ($row);//Read all data with a loop: while ($row =mysql_fetch_row ($result)) {var_dump ($row); }

method Two: Object-oriented

1. Create a Connection object:

$db =new mysqli ("localhost", "root", "123", "mydb")//in parentheses the contents are "server address", "username", "password", "Database name"

2. Determine if the connection is faulty:

2.1 Mysqli_connect_error (); Error on behalf of connection

2.2

if (Mysqli_connect_erroe ())

{

echo "Connection failed!";

Exit (); Exit program

}

2.3!mysqli_connect_error or Die ("Connection failed! "); "or" Before the connection is correct, which means the connection failed

3. Write the SQL statement:

$sql = "SELECT * From Nation";

4. Execute SQL statement: If the execution succeeds in returning the result set object, if the execution fails returns false

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

5. Read the data from the result set, first determine if there is any data

if ($result) {//Returns an indexed array of rows of data, each execution returns a data Var_dump ($result->fetch_row ());　　while ($row = $result->fetch_row) {var_dump ($row); 　　}//Returns an associative array of rows of data, with each execution returning a data var_dump ($result->fetch_row ());　　Returns all data Var_dump ($result->fetch_all ()) through a two-dimensional array; Returns a row of data as an object Var_dump ($result->fetch_object ());}

Practice:

1. The form of the following drop-down menu displays the Nation table on the page

$db =new mysqli ("localhost", "root", "" "," MyDB ");! Mysqli_connection_erroe () or Die ("Connection failed!　　$sql = "Select*from Nation", $result = $db->query ($sql), if ($result) {$att = $result->fetch_all (); echo ""; foreach ($att as $value) {echo '{$value [1]} "; } echo "";}

2. Find out the Info table and display it in tabular form

$db =new mysqli ("localhost", "root", "" "," MyDB ");! Mysqli_connecton_error () or Die ("Connection failed! $sql = "SELECT * from Info", $result = $bd->query ($sql), if ($result) {$att = $result->fetch_all (); echo "
 
 
  
  "; Echo"
  
  "; foreach ($att as $value) {echo" 
   ";} echo " 
  
 
   
 
    
Code
 
    
Name
 
    
Gender
 
    
National
 
    
Birthday
 
   
 
    
{$value [0]}
 
    
{$value [1]}
 
    
{$value [2]}
 
    
{$value [3]}
 
    
{$value [4]}
 
   

 
 
";}　　You can also use the For loop if ($result) {$arr = $result->fetch_all (); echo "
 
  
 　　　　

 
 
 
  
  "; echo "
  
  "; for ($i =0; $i 
   　　　　 
    　　　　 
    　　　　 
    　　　　 
     　　　　 
   "; } echo " 
  
 
   
 
    
Code
 
    
Name
 
    
Sex
 
    
Nation
 
    
Birthday
 
   
 
    
{$arr [$i][0]}
{$arr [$i][1]}
{$arr [$i][2]}
{$arr [$i][3]}
{$arr [$i][4]}

 
 
";}</tr>

The above is the whole content of this article, I hope that you learn PHP programming help.

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