Php Note 1-php Tutorial

Php note 1. Login verification steps:

1. assign values. use $ _ POST to pass the id and password to the loginProcess. php login verification page.

2. create a database connection $ conn = mysql_connect ($ host, $ username, $ password );

3. select the database mysql_select_db (empmanage );

4. define the SQL statement $ SQL = "select password from admin ";

5. execute the SQL statement and obtain the result $ res = mysql_query ($ SQL, $ conn );

6. compare the password (condition statement)

If ($ row = mysql_fetch_assco ($ res )){

If ($ password = $ row ['password']) {

// The verification is successful and you are redirected to the specified page.

Header ("Location: emp. php ");

Exit ();

} Else {

// If verification fails, return to the login page.

Header ("Location: login. php? Error = 1 ");

Exit ();

}

}

7. release the resource mysql_free_result ($ res );

8. close the connection (automatic) mysql_close ($ conn );

2. several PHP writing principles:

1. release resources from where they are generated

2. close the connection

3. stratified thinking ?????? Very important.

4. a function can return only one result.

3. object-oriented programming, which encapsulates common tool classes.

(For details, refer to the php folder)

IV. cookie knowledge points

1. how to create a cookie?

The setcookie () function is used to set the cookie.

Note: The setcookie () function must be locatedBefore the tag.

Syntax:

Setcookie (name, value, expire, path, domain );

Note:

2. how can I retrieve the Cookie value?

The $ _ COOKIE variable of PHP is used to retrieve the cookie value.

For example, in the following example, we use the isset () function to check whether the cookie has been set:

If (isset ($ _ COOKIE ["user"])

Echo "Welcome". $ _ COOKIE ["user"]. "!
"; // Cookie itself is a super Global array;

Else

Echo "cookie does not exist
";

?>

3. if you enter Chinese characters, the browser will Recode urlencode and can also use urldecode for decoding.

Example:

V. Time zone problems

Q: Why is the date () function used in PHP 8 hours different from the current local time?

Method 1:
Date_default_timezone_set ('prc ');
No return value. Now we can use the date function directly.
$ Time = date (Y. "year". m. "month". d. "day". G. "hour". I. "minute ");

Method 2:

In php. ini, modify date. timezone = to date. timezone = "Asia/Shanghai" (or change to date. timezone = PRC), remove the semicolon, and restart Apache.