mysqli的使用

<?php
/**
数据库连接

**/
$conn=mysqli_connect(‘localhost:3306‘,‘root‘,‘root‘);
if(!$conn){
    die("could not connect:".mysqli_error($conn));
}
mysqli_query($conn , "set names utf8");
$sec=mysqli_select_db($conn,‘wc‘);
if(!$sec){
    die("error".mysqli_error($conn));
}
$sql="select * from ss";
$retval=mysqli_query($conn,$sql);
if(!$retval){
    die("无法读取数据：".mysqli_error($conn));
}
print_r($retval);
while($row=mysqli_fetch_array($retval,MYSQLI_ASSOC)){
    echo ‘<br/>‘;
    print_r($row);
    $arr[]=$row;
}
var_dump($arr);
mysqli_free_result($retval);
mysqli_close($conn);
/*3中解析方法
mysqli_fetch_array($retval)查询结果
Array ( [0] => 1 [id] => 1 [1] => 12 [a] => 12 [2] => 34 [b] => 34 [3] => 11 [c] => 11 ) 
Array ( [0] => 2 [id] => 2 [1] => 65 [a] => 65 [2] => 42 [b] => 42 [3] => 16 [c] => 16 ) 
Array ( [0] => 3 [id] => 3 [1] => 91 [a] => 91 [2] => 95 [b] => 95 [3] => 93 [c] => 93 )
mysqli_fetch_array($retval,MYSQLI_ASSOC)
Array ( [id] => 1 [a] => 12 [b] => 34 [c] => 11 ) 
Array ( [id] => 2 [a] => 65 [b] => 42 [c] => 16 ) 
Array ( [id] => 3 [a] => 91 [b] => 95 [c] => 93 )

mysqli_fetch_assoc($retval)查询结果
Array ( [id] => 1 [a] => 12 [b] => 34 [c] => 11 ) 
Array ( [id] => 2 [a] => 65 [b] => 42 [c] => 16 ) 
Array ( [id] => 3 [a] => 91 [b] => 95 [c] => 93 )
//mysqli_fetch_row($retval)
Array ( [0] => 1 [1] => 12 [2] => 34 [3] => 11 ) 
Array ( [0] => 2 [1] => 65 [2] => 42 [3] => 16 ) 
Array ( [0] => 3 [1] => 91 [2] => 95 [3] => 93 )
//mysqli_fetch_field($retval)
stdClass Object ( [name] => id [orgname] => id [table] => ss [orgtable] => ss [def] => [db] => wc [catalog] => def [max_length] => 1 [length] => 11 [charsetnr] => 63 [flags] => 49667 [type] => 3 [decimals] => 0 ) 
stdClass Object ( [name] => a [orgname] => a [table] => ss [orgtable] => ss [def] => [db] => wc [catalog] => def [max_length] => 2 [length] => 11 [charsetnr] => 63 [flags] => 32768 [type] => 3 [decimals] => 0 ) 
stdClass Object ( [name] => b [orgname] => b [table] => ss [orgtable] => ss [def] => [db] => wc [catalog] => def [max_length] => 2 [length] => 11 [charsetnr] => 63 [flags] => 32768 [type] => 3 [decimals] => 0 ) 
stdClass Object ( [name] => c [orgname] => c [table] => ss [orgtable] => ss [def] => [db] => wc [catalog] => def [max_length] => 2 [length] => 11 [charsetnr] => 63 [flags] => 32768 [type] => 3 [decimals] => 0 )
*/