PHP Access database

To access the database steps:

1. Create a Connection object

1 $db = new mysqli ("localhost", "root", "123", "MyDB");

2. Determine if the connection is wrong

1 ! Mysqli_connect_error () or die ("Connection failed! ");

3. Write SQL statements

1 $sql = "SELECT * from Info";

4. Execute SQL statement, query statement if execution succeeds return result set object, if execution fails return false

1 $result = $db->query ($sql);

5. Reading data from the result set

if($result){    Var_dump($result->fetch_row ());//returns an array of rows of data (indexed array)     while($row=$result-Fetch_row ()) {        Var_dump($row); }        Var_dump($result->FETCH_ASSOC ());//returns a row of data (associative array)        $shuju=$result->fetch_all ();//return all data (two-dimensional array)        Var_dump($result->fetch_object ());//returns a row of data (objects)}

Example: Show the National column in the Nation table in the form of a drop-down list

//1. Making Connection Objects$db=NewMysqli ("localhost", "root", "123", "MyDB");//2. Determine if there is an error!Mysqli_connect_error() or die("Connection Failed! ");//3. Write SQL statements$sql= "SELECT * FROM Nation";//4. Execute SQL statements$result=$db->query ($sql);//5. Fetching Dataif($result){    $attr=$result-Fetch_all (); Echo"<select>"; foreach($attr  as $v)        {            Echo"<option value= ' {$v[0]} ' >{$v[1]} </option> "; }            Echo"</select>";}

PHP Access database