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    What's the diff between function isset() and empty()? I was totally confused.

    I create a table with mysql as:
    ---------------------code-
    create table user(
    id int not null auto increment,
    name varchar(64) not null,
    age int null,
    description text null,
    primary key(id),
    index(name)
    );
    ---------------------code+

    The description is set to null in case someone don't like to introduce himself/herself.
    The age is set to null in case someone don't want to tell the other his/her age.

    Then I have a form where user put their information and a PHP file to handle these information.
    Assume the new user input only his/her name, then
    isset($name)==true and empty($name)==false
    isset($age)==true and empty($age)==true
    isset($description)==true and empty($description)==true
    I use following scripts to insert the new user's information:
    -----------------------------code-
    insert into user(name,age,description) values($name,$age,$des)
    -----------------------------code+

    Then I will display the information:
    -----------------------------code-
    $qid = mysql_query("select name,age,description from user where id='$the_user_id'");
    $user = mysql_fetch_object($qid);
    -----------------------------code+

    then, the following two lines are confused me
    -----------------------------code-
    echo "$user->age"; //error: undefind property
    echo "$user->description"; //right
    -----------------------------code+

    I will appreciate if some one can help me !

    another question, see following urls:
    ----------------------------urls-
    domainname/user.php?id=3
    domainname/user.php?id=
    domainname/user.php
    ----------------------------urls+

    What about the variable "$id" in user.php ? I know $id is set and value is 3 according to 1st url.
    It is: isset($id)==true and empty($id)==false

    What about the other two?

    ------------------
    Good Good Study
    Day Day Up

    [This message has been edited by xiaoguiwxd (edited September 18, 2000).]
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    Actually both the functions used for determining wether a variable is set or not.

    if you are using empty() function with a variable,it will check wether it is zero or it not holding a value.. then it will return true.

    eg:

    <?
    $variable=0;

    if(empty($variable)){
    echo "it is working fine and it is empty or zero";
    }
    //it checks for 0 or no values and return 'true'...
    ?>


    second case , if you are using isset() will check again wether the variable is set or not..it is a very regularly using function for checking wether variable is set or not..


    eg:

    <?
    $variable="hello";

    if(isset($variable)){
    echo "yea,variable is set";
    }
    ?>


    empty function will return true if it is not having any value..

    isset function will return true if the variable is set..

    see the manual for more details...

    ------------------
    SR -
    webshiju.com
    www.jobxyz.com-IT Career Portal
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    "The fear of the LORD is the beginning of knowledge..."


    [This message has been edited by Shiju Rajan (edited September 18, 2000).]

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