Differences between mysqli and MySQL and fetch_row and fetch_array

I. mysqli. dll is an object-based or process-based database that is easy to use. Here we will compare several common operations with MySQL. dll.

1: mysql. dll (which can be understood as a functional method ):

$ Conn = mysql_connect ('localhost', 'user ',
'Password'); // connect to the MySQL database
Mysql_select_db ('data _ base', $ conn );
// Select a database

$ Result = mysql_query ('select * from
Data_base '); // the second optional parameter specifies the connection to be opened.

$ ROW = mysql_fetch_row ($ result) // For simplicity, only one row of data is taken.
Echo $ row [0];
// Output the value of the first field

Mysqli also has a program method, but starts to use the mysqli prefix, and the others are similar. If mysqli operates in a procedural manner, some functions must specify resources, such
Mysqli_query (resource ID, SQL statement), and the resource ID parameters are placed in front, while the resource ID of mysql_query (SQL statement, 'optional ') is put
It can be left unspecified. By default, it is the last opened connection or resource.

2mysqli. dll (Object method ):

$ Conn = new mysqli ('localhost', 'user ',
'Password', 'Data _ base ');
// The connection here is new. The last parameter is to specify the database directly without mysql_select_db ().
// You can also choose not to specify it during the construction, and then
$ Conn-> select_db ('data _ base ')

$ Result = $ Conn-> query ('select * From data_base ');
$ ROW = $ result
-> Fetch_row (); // fetch a row of data
Echo row [0]; // output the value of the first field

Ii. mysql_fetch_row (), mysql_fetch_array ()

The two functions return an array. The difference is that the array returned by the first function only contains values. We can only $ row [0].
$ Row [1], which reads data by the array subscript. The array returned by mysql_fetch_array () contains both the first and key values.
In the correct format, we can read data like this (assume that the database field is
Username, passwd ):

$ Row ['username'], $ row ['passwd']

In addition, if you use ($ row as $ Kay =>
$ Value) to directly obtain the database field name.
What's more, mysqli is a new function library provided by PhP5. (I) indicates improvement and its execution speed is faster.

For example:

<? PHP

// Connect to the local MySQL database and select test as the operating database
$ Mysqli = mysqli_connect ("localhost ",
"Root", "", "test", 3306 );
// Use the mysql_query function to read data from the user table
$ Result =
Mysqli_query ($ mysqli, "select * From userinfo ");
While ($ ROW =
Mysqli_fetch_array ($ result) // read the data content cyclically.
{
?>
<Tr>
<TD
Align = "center" Height = "19"> <? PHP echo $ row ["ID"]?> </TD>
<TD
Align = "center"> <? PHP echo $ row ["name"]?> </TD>
<TD
Align = "center"> <? PHP echo
$ Row ["detail"]?> </TD>
</Tr>
<? PHP
}
// Close the connection to the database
Mysqli_free_result ($ result );
Mysqli_close ($ mysqli );*/
?>