Re: [PHP] Classes vs. functions?
Can someone please explain to me when is a class useful over a set of functions? Almost always. Object oriented programming offers many many advantages (that I cannot get into depth on here). There are a few exceptions where you would not use classes, such as utility functions like max() and min() that would be used generically. The most basic purpose of a class is to define your own 'type' of object. When you create a class you are encapsulating an 'idea' into a set of attributes and behaviors specific to that type. Designing classes not only offers a great way of organizing code but inevitably forces you to think thoroughly about the logical separation of code and to refine more and more towards an idealized type with well defined and sensible behavior. Conversely non-object oriented programming tends to lack in clarity and intended usage, making it difficult and confusing to use, getting exponentially worse for complex problems. Classes have methods (functions) that are designed to work specifically on members of that class or perform operations directly related to it. Plain functions, however, have a tendency to be vague and complicated by argument lists. Furthermore they are easier to be misused and can be prone to latent errors. In the end, it's like driving a car: the engine is neatly hidden under the hood and you don't care or want to know about the internal workings of it. You just want to get in, turn the key and drive. Classes are no different... they provide a simplified user-friendly interface to complex things. It's luxury in programming :) I would suggest getting some books to learn further, and just start using classes. Steven J. Walker Walker Effects www.walkereffects.com [EMAIL PROTECTED] On Monday, June 2, 2003, at 08:31 PM, Vijay Avarachen wrote: I have been mostly using function in my php code, and lately I have been curious about classes. I have a vague idea of classes from my C++ class that I took a few years back. Can someone please explain to me when is a class useful over a set of functions? I have seen very few code with classes, so pretty much always stayed away from it. Thanks, Vijay Avarachen -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Classes vs. functions?
Here is an excellent article describing classes/objects - what they are and are not. http://phpmag.net/itr/online_artikel/psecom,id,284,nodeid,114.html olinux Can someone please explain to me when is a class useful over a set of functions? __ Do you Yahoo!? Yahoo! Calendar - Free online calendar with sync to Outlook(TM). http://calendar.yahoo.com -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Classes vs. Functions
Thank you for your 2 cents I am just learning and appreciate your comments. - Original Message - From: Michael Hall [EMAIL PROTECTED] To: Chris Crane [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Sent: Tuesday, July 16, 2002 11:13 PM Subject: Re: [PHP] Classes vs. Functions There is no simple answer here. I have started using classes where I find I am writing a lot of related functions that share similar parameters. Database connection and queries are a good example. Authentication is another. I have another class that builds forms, because I just hate the tedium of coding HTML forms by hand. It is really just a collection of functions, though, and could work fine as such. I'm still learning/exploring ... I am always guided by the principle that whatever makes less work for me (but achieves the same result) is probably a good thing. IMHO classes are best for more universal code that really can be used in many different places. My functions tend to be more application specific. My 2 cents Michael On Tue, 16 Jul 2002, Chris Crane wrote: Could someone please explain the difference between classes and functions and how to use a class. I write alot of PHP, but I never understood this at all. I use an include statement in many of my pages and include a file with a bunch of functions. For instance, I might have a function called stock(); In the page I am using I include the file that has this function and I call it like this: stock($Sym); I am wondering if I am doing it the wrong way. So I need to better understand classes. What is one, and why would you use it? Thanks. -- n i n t i . c o m php-python-perl-mysql-postgresql Michael Hall [EMAIL PROTECTED] -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] Classes vs. Functions
[snip] Could someone please explain the difference between classes and functions and how to use a class. I write alot of PHP, but I never understood this at all. I use an include statement in many of my pages and include a file with a bunch of functions. For instance, I might have a function called stock(); In the page I am using I include the file that has this function and I call it like this: stock($Sym); I am wondering if I am doing it the wrong way. So I need to better understand classes. What is one, and why would you use it? [/snip] A class is the representation of an object, such as a person, place, or thing. A function is a group of commands that can be called for a specific purpose. function addNumbers() A function can be performed on an object, but an object (the logical extension of class) cannot be performed on a function. Does that help? Jay Cleverly disguised as a responsible adult * * Want to meet other PHP developers * * in your area? Check out: * * http://php.meetup.com/* * No developer is an island ... * * -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] Classes vs. Functions
To add to the below, object classes, can have their own set of functions, called methods. These methods are specific to the function, and ALL functions within a class treat any properties (variables) within the class as global. So if you have a class Car with two properties (Make and Model), then those two properties can be readily accessible to any method within the class. At least I think that's how it works. I'm not all that knowledgeable on the subject :o) Martin Clifford Homepage: http://www.completesource.net Developer's Forums: http://www.completesource.net/forums/ Jay Blanchard [EMAIL PROTECTED] 07/16/02 10:51AM [snip] Could someone please explain the difference between classes and functions and how to use a class. I write alot of PHP, but I never understood this at all. I use an include statement in many of my pages and include a file with a bunch of functions. For instance, I might have a function called stock(); In the page I am using I include the file that has this function and I call it like this: stock($Sym); I am wondering if I am doing it the wrong way. So I need to better understand classes. What is one, and why would you use it? [/snip] A class is the representation of an object, such as a person, place, or thing. A function is a group of commands that can be called for a specific purpose. function addNumbers() A function can be performed on an object, but an object (the logical extension of class) cannot be performed on a function. Does that help? Jay Cleverly disguised as a responsible adult * * Want to meet other PHP developers * * in your area? Check out: * * http://php.meetup.com/* * No developer is an island ... * * -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Classes vs. Functions
It helps a little bit, thank you. Could you provide some code as to what a Class looks like. I am just trying to understand it better and if I see it, it might help. Jay Blanchard [EMAIL PROTECTED] wrote in message 000401c22cd8$54ce9ce0$8102a8c0@niigziuo4ohhdt">news:000401c22cd8$54ce9ce0$8102a8c0@niigziuo4ohhdt... [snip] Could someone please explain the difference between classes and functions and how to use a class. I write alot of PHP, but I never understood this at all. I use an include statement in many of my pages and include a file with a bunch of functions. For instance, I might have a function called stock(); In the page I am using I include the file that has this function and I call it like this: stock($Sym); I am wondering if I am doing it the wrong way. So I need to better understand classes. What is one, and why would you use it? [/snip] A class is the representation of an object, such as a person, place, or thing. A function is a group of commands that can be called for a specific purpose. function addNumbers() A function can be performed on an object, but an object (the logical extension of class) cannot be performed on a function. Does that help? Jay Cleverly disguised as a responsible adult * * Want to meet other PHP developers * * in your area? Check out: * * http://php.meetup.com/* * No developer is an island ... * * -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] Classes vs. Functions
[snip] example? [/snip] http://www.devshed.com/Server_Side/PHP/FormValidatorClass/page1.html Good tutorial Jay * * Want to meet other PHP developers * * in your area? Check out: * * http://php.meetup.com/* * No developer is an island ... * * -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Classes vs. Functions
Here is a sample code (don't take this as gospel... Jay knows more about OOP than I
do, I'm sure!):
class Car {
var $make;
var $model;
function setMake($x) {
$this-make = $x;
}
function setModel($y) {
$this-model = $y;
}
}
$make and $model are the properties of the Car class, and setMake() and setModel() are
the methods of the Car class. You don't actually get an object until make a *new*
one. Like this:
$passat = new Car;
$passat-setMake(Volkswagen);
$passat-setModel(Passat);
This assigns the new object, passat, the properties relating to it's make and model,
using the methods setMake and setModel. I'm sure this is right, but I'm sure I'm
probably wrong (hehe, confused?). I'm also sure someone will correct me if I am! :o)
Martin Clifford
Homepage: http://www.completesource.net
Developer's Forums: http://www.completesource.net/forums/
Chris Crane [EMAIL PROTECTED] 07/16/02 11:06AM
It helps a little bit, thank you. Could you provide some code as to what a
Class looks like. I am just trying to understand it better and if I see it,
it might help.
Jay Blanchard [EMAIL PROTECTED] wrote in message
000401c22cd8$54ce9ce0$8102a8c0@niigziuo4ohhdt">news:000401c22cd8$54ce9ce0$8102a8c0@niigziuo4ohhdt...
[snip]
Could someone please explain the difference between classes and functions
and how to use a class. I write alot of PHP, but I never understood this
at
all. I use an include statement in many of my pages and include a file
with
a bunch of functions. For instance, I might have a function called
stock();
In the page I am using I include the file that has this function and I
call
it like this:
stock($Sym);
I am wondering if I am doing it the wrong way. So I need to better
understand classes. What is one, and why would you use it?
[/snip]
A class is the representation of an object, such as a person, place, or
thing.
A function is a group of commands that can be called for a specific
purpose.
function addNumbers()
A function can be performed on an object, but an object (the logical
extension of class) cannot be performed on a function. Does that help?
Jay
Cleverly disguised as a responsible adult
*
* Want to meet other PHP developers *
* in your area? Check out: *
* http://php.meetup.com/*
* No developer is an island ... *
*
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Classes vs. Functions
This helps quite a bit Thank you.
I am just wondering if I should make classes instead of functions? What
would be the benefit of that? Do you know?
Martin Clifford [EMAIL PROTECTED] wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
Here is a sample code (don't take this as gospel... Jay knows more about OOP
than I do, I'm sure!):
class Car {
var $make;
var $model;
function setMake($x) {
$this-make = $x;
}
function setModel($y) {
$this-model = $y;
}
}
$make and $model are the properties of the Car class, and setMake() and
setModel() are the methods of the Car class. You don't actually get an
object until make a *new* one. Like this:
$passat = new Car;
$passat-setMake(Volkswagen);
$passat-setModel(Passat);
This assigns the new object, passat, the properties relating to it's make
and model, using the methods setMake and setModel. I'm sure this is right,
but I'm sure I'm probably wrong (hehe, confused?). I'm also sure someone
will correct me if I am! :o)
Martin Clifford
Homepage: http://www.completesource.net
Developer's Forums: http://www.completesource.net/forums/
Chris Crane [EMAIL PROTECTED] 07/16/02 11:06AM
It helps a little bit, thank you. Could you provide some code as to what a
Class looks like. I am just trying to understand it better and if I see it,
it might help.
Jay Blanchard [EMAIL PROTECTED] wrote in message
000401c22cd8$54ce9ce0$8102a8c0@niigziuo4ohhdt">news:000401c22cd8$54ce9ce0$8102a8c0@niigziuo4ohhdt...
[snip]
Could someone please explain the difference between classes and functions
and how to use a class. I write alot of PHP, but I never understood this
at
all. I use an include statement in many of my pages and include a file
with
a bunch of functions. For instance, I might have a function called
stock();
In the page I am using I include the file that has this function and I
call
it like this:
stock($Sym);
I am wondering if I am doing it the wrong way. So I need to better
understand classes. What is one, and why would you use it?
[/snip]
A class is the representation of an object, such as a person, place, or
thing.
A function is a group of commands that can be called for a specific
purpose.
function addNumbers()
A function can be performed on an object, but an object (the logical
extension of class) cannot be performed on a function. Does that help?
Jay
Cleverly disguised as a responsible adult
*
* Want to meet other PHP developers *
* in your area? Check out: *
* http://php.meetup.com/*
* No developer is an island ... *
*
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] Classes vs. Functions
$this-numberrows; $x++) {
$this-result[$x] = mysql_fetch_row($this-qry);
}
} else {
//echo([Error:] Retrieving data);
return false;
}
return true;
}
}
function insertquery() {
global $TRUE, $FALSE;
if ($this-dbconnection == $FALSE) {
$this-opendbconnection();
}
$this-qry = mysql_query($this-sql);
if (!$this-qry) {
return false;
} else {
return true;
}
}
function deletequery() {
global $TRUE, $FALSE;
if ($this-dbconnection == $FALSE) {
$this-opendbconnection();
}
$this-qry = mysql_query($this-sql);
if (!$this-qry) {
return false;
} else {
return true;
}
}
function updatequery() {
global $TRUE, $FALSE;
if ($this-dbconnection == $FALSE) {
$this-opendbconnection();
}
$this-qry = mysql_query($this-sql);
if (!$this-qry) {
return false;
} else {
return true;
}
}
}
?
And now in any .php file you include this .obj file and use it as follows.
$db1 = new mysqldb(); // create a new instance of the mysql object.
// You can create as many as you want and
the great thing is
// that each instances vars will contain
there own data.
$sql = Insert into ...;
$db1-setTransactionSwitch(true);
$db1-begin(); //this will begin a transaction (InnoDb or BDB tables
are required for this)
$db1-setsql($sql); //set the objects $sql variable.
if (!$db1-insertquery()) //now call the method that does
all the work so
$db1-setTransactionSwitch(false); //you don't have to recode it.
If it fails roolback.
if($db1-getTransactionSwitch()==false);{
$db1-rollback();
}else{
$db1-commit();
}
Classes allow you to have multple instances of an object containing
seperate info, makes it easier to keep track of.
Hope this helps,
Steve.
-Original Message-
From: Chris Crane [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, July 16, 2002 11:07 AM
To: [EMAIL PROTECTED]
Subject: Re: [PHP] Classes vs. Functions
It helps a little bit, thank you. Could you provide some code as to what a
Class looks like. I am just trying to understand it better and if I see it,
it might help.
Jay Blanchard [EMAIL PROTECTED] wrote in message
000401c22cd8$54ce9ce0$8102a8c0@niigziuo4ohhdt">news:000401c22cd8$54ce9ce0$8102a8c0@niigziuo4ohhdt...
[snip]
Could someone please explain the difference between classes and functions
and how to use a class. I write alot of PHP, but I never understood this
at
all. I use an include statement in many of my pages and include a file
with
a bunch of functions. For instance, I might have a function called
stock();
In the page I am using I include the file that has this function and I
call
it like this:
stock($Sym);
I am wondering if I am doing it the wrong way. So I need to better
understand classes. What is one, and why would you use it?
[/snip]
A class is the representation of an object, such as a person, place, or
thing.
A function is a group of commands that can be called for a specific
purpose.
function addNumbers()
A function can be performed on an object, but an object (the logical
extension of class) cannot be performed on a function. Does that help?
Jay
Cleverly disguised as a responsible adult
*
* Want to meet other PHP developers *
* in your area? Check out: *
* http://php.meetup.com/*
* No developer is an island ... *
*
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] Classes vs. Functions
[snip] This helps quite a bit Thank you. I am just wondering if I should make classes instead of functions? What would be the benefit of that? Do you know? [/snip] You should keep classes and functions seperate in your thought process, they are not the same and not meant to do or be the same thing. Here is a good thought process to apply to classes... 1. Is this an object? If the answer is no, you do not need a class. 2. Do I need to do something (have an action or set of actions performed), perhaps over and over again? If the answer is yes, this is a function. A method is a function that applies to a specific class of objects. If you created a class and methods for each item you code would be bloated, slow, and hard to maintain. Do not think of functions and classes in the same light, you will make yourself more confused. One is definitely not the other. Jay * * Want to meet other PHP developers * * in your area? Check out: * * http://php.meetup.com/* * No developer is an island ... * * -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Classes vs. Functions
I'm still trying to figure that out, but the fog is clearing slowly but steadily :o)
From what I've heard on this and other lists, it's all a matter of preference.
Obviously those that come from an object-oriented environment (Java, etc), will lean
toward this method, while others stay with the procedural side of things (using
functions). It's all a matter of preference, and just yet I haven't decided which is
more useful :o)
Good luck!
Martin Clifford
Homepage: http://www.completesource.net
Developer's Forums: http://www.completesource.net/forums/
Chris Crane [EMAIL PROTECTED] 07/16/02 11:19AM
This helps quite a bit Thank you.
I am just wondering if I should make classes instead of functions? What
would be the benefit of that? Do you know?
Martin Clifford [EMAIL PROTECTED] wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
Here is a sample code (don't take this as gospel... Jay knows more about OOP
than I do, I'm sure!):
class Car {
var $make;
var $model;
function setMake($x) {
$this-make = $x;
}
function setModel($y) {
$this-model = $y;
}
}
$make and $model are the properties of the Car class, and setMake() and
setModel() are the methods of the Car class. You don't actually get an
object until make a *new* one. Like this:
$passat = new Car;
$passat-setMake(Volkswagen);
$passat-setModel(Passat);
This assigns the new object, passat, the properties relating to it's make
and model, using the methods setMake and setModel. I'm sure this is right,
but I'm sure I'm probably wrong (hehe, confused?). I'm also sure someone
will correct me if I am! :o)
Martin Clifford
Homepage: http://www.completesource.net
Developer's Forums: http://www.completesource.net/forums/
Chris Crane [EMAIL PROTECTED] 07/16/02 11:06AM
It helps a little bit, thank you. Could you provide some code as to what a
Class looks like. I am just trying to understand it better and if I see it,
it might help.
Jay Blanchard [EMAIL PROTECTED] wrote in message
000401c22cd8$54ce9ce0$8102a8c0@niigziuo4ohhdt">news:000401c22cd8$54ce9ce0$8102a8c0@niigziuo4ohhdt...
[snip]
Could someone please explain the difference between classes and functions
and how to use a class. I write alot of PHP, but I never understood this
at
all. I use an include statement in many of my pages and include a file
with
a bunch of functions. For instance, I might have a function called
stock();
In the page I am using I include the file that has this function and I
call
it like this:
stock($Sym);
I am wondering if I am doing it the wrong way. So I need to better
understand classes. What is one, and why would you use it?
[/snip]
A class is the representation of an object, such as a person, place, or
thing.
A function is a group of commands that can be called for a specific
purpose.
function addNumbers()
A function can be performed on an object, but an object (the logical
extension of class) cannot be performed on a function. Does that help?
Jay
Cleverly disguised as a responsible adult
*
* Want to meet other PHP developers *
* in your area? Check out: *
* http://php.meetup.com/*
* No developer is an island ... *
*
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Classes vs. Functions
thanks Jay. Jay Blanchard [EMAIL PROTECTED] wrote in message 000e01c22cdd$0d0c7530$8102a8c0@niigziuo4ohhdt">news:000e01c22cdd$0d0c7530$8102a8c0@niigziuo4ohhdt... [snip] This helps quite a bit Thank you. I am just wondering if I should make classes instead of functions? What would be the benefit of that? Do you know? [/snip] You should keep classes and functions seperate in your thought process, they are not the same and not meant to do or be the same thing. Here is a good thought process to apply to classes... 1. Is this an object? If the answer is no, you do not need a class. 2. Do I need to do something (have an action or set of actions performed), perhaps over and over again? If the answer is yes, this is a function. A method is a function that applies to a specific class of objects. If you created a class and methods for each item you code would be bloated, slow, and hard to maintain. Do not think of functions and classes in the same light, you will make yourself more confused. One is definitely not the other. Jay * * Want to meet other PHP developers * * in your area? Check out: * * http://php.meetup.com/* * No developer is an island ... * * -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Classes vs. Functions
Is there an advantage to Classes vs. Functions? Jay Blanchard [EMAIL PROTECTED] wrote in message 000c01c22cdb$11485c10$8102a8c0@niigziuo4ohhdt">news:000c01c22cdb$11485c10$8102a8c0@niigziuo4ohhdt... [snip] example? [/snip] http://www.devshed.com/Server_Side/PHP/FormValidatorClass/page1.html Good tutorial Jay * * Want to meet other PHP developers * * in your area? Check out: * * http://php.meetup.com/* * No developer is an island ... * * -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Classes vs. Functions
urn true;
}
}
function selectquery() {
global $TRUE, $FALSE;
if ($this-dbconnection == $FALSE) {
$this-opendbconnection();
}
$this-qry = mysql_query($this-sql);
if (!$this-qry) {
return false;
} else {
$this-numberrows = mysql_num_rows($this-qry);
if ($this-numberrows 0) {
for($x = 0; $x $this-numberrows; $x++) {
$this-result[$x] = mysql_fetch_row($this-qry);
}
} else {
//echo([Error:] Retrieving data);
return false;
}
return true;
}
}
function insertquery() {
global $TRUE, $FALSE;
if ($this-dbconnection == $FALSE) {
$this-opendbconnection();
}
$this-qry = mysql_query($this-sql);
if (!$this-qry) {
return false;
} else {
return true;
}
}
function deletequery() {
global $TRUE, $FALSE;
if ($this-dbconnection == $FALSE) {
$this-opendbconnection();
}
$this-qry = mysql_query($this-sql);
if (!$this-qry) {
return false;
} else {
return true;
}
}
function updatequery() {
global $TRUE, $FALSE;
if ($this-dbconnection == $FALSE) {
$this-opendbconnection();
}
$this-qry = mysql_query($this-sql);
if (!$this-qry) {
return false;
} else {
return true;
}
}
}
?
And now in any .php file you include this .obj file and use it as follows.
$db1 = new mysqldb(); // create a new instance of the mysql object.
// You can create as many as you want and
the great thing is
// that each instances vars will contain
there own data.
$sql = Insert into ...;
$db1-setTransactionSwitch(true);
$db1-begin(); //this will begin a transaction (InnoDb or BDB tables
are required for this)
$db1-setsql($sql); //set the objects $sql variable.
if (!$db1-insertquery()) //now call the method that
does
all the work so
$db1-setTransactionSwitch(false); //you don't have to recode
it.
If it fails roolback.
if($db1-getTransactionSwitch()==false);{
$db1-rollback();
}else{
$db1-commit();
}
Classes allow you to have multple instances of an object containing
seperate info, makes it easier to keep track of.
Hope this helps,
Steve.
-Original Message-
From: Chris Crane [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, July 16, 2002 11:07 AM
To: [EMAIL PROTECTED]
Subject: Re: [PHP] Classes vs. Functions
It helps a little bit, thank you. Could you provide some code as to what a
Class looks like. I am just trying to understand it better and if I see
it,
it might help.
Jay Blanchard [EMAIL PROTECTED] wrote in message
000401c22cd8$54ce9ce0$8102a8c0@niigziuo4ohhdt">news:000401c22cd8$54ce9ce0$8102a8c0@niigziuo4ohhdt...
[snip]
Could someone please explain the difference between classes and
functions
and how to use a class. I write alot of PHP, but I never understood this
at
all. I use an include statement in many of my pages and include a file
with
a bunch of functions. For instance, I might have a function called
stock();
In the page I am using I include the file that has this function and I
call
it like this:
stock($Sym);
I am wondering if I am doing it the wrong way. So I need to better
understand classes. What is one, and why would you use it?
[/snip]
A class is the representation of an object, such as a person, place, or
thing.
A function is a group of commands that can be called for a specific
purpose.
function addNumbers()
A function can be performed on an object, but an object (the logical
extension of class) cannot be performed on a function. Does that help?
Jay
Cleverly disguised as a responsible adult
*
* Want to meet other PHP developers *
* in your area? Check out: *
* http://php.meetup.com/*
* No developer is an island ... *
*
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] Classes vs. Functions
Yes any vars used in a class have to be defined ahead. Then just write quick
set and get mothods to change them.
And the important thing to remember is $db1-Host; retrieved with
$db1-getHost(); for example contains seperate data then $db2-$Host;
Good luck.
-Original Message-
From: Chris Crane [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, July 16, 2002 11:40 AM
To: [EMAIL PROTECTED]
Subject: Re: [PHP] Classes vs. Functions
Wow...this is pretty cool.
Do you HAVE to declareall your varibles ahead of time?
Steve Bradwell [EMAIL PROTECTED] wrote in message
57A1618E7109D311A97D0008C7EBB3A1010C8258@KITCHENER">news:57A1618E7109D311A97D0008C7EBB3A1010C8258@KITCHENER...
Classes are great for code reusability, I heavily use a MySQL object or
class to make all my conections to a mysql database now and I have
included
methods for Transactions.
Its a long one but its the class I use the most and is a great example of
what they are good for.
?
class mysqldb { //so here define the name of the class.
//set up the object, these are the variables that are accessible by
each
instance you create
// of an object.
var $host;
var $db;
var $dbuser;
var $dbpassword;
var $sql;
var $numberrows;
var $dbopenstatus;
var $dbconnection;
var $qry;
var $result;
var $TransactionSwitch;
/*
Use these functions to get and set the values of this object's
variables. This is good OO practice, as it means that datatype
checking can be completed and errors raised accordingly.
*/
// Property Get Set these methods are used set class vars and to
retrieve them.
function gethost() {
return $this-dbhost;
}
function sethost($req_host) {
$this-dbhost = $req_host;
}
function getdb() {
return $this-db;
}
function setdb($req_db) {
$this-db = $req_db;
}
function getdbuser() {
return $this-dbuser;
}
function setdbuser($req_user) {
$this-dbuser = $req_user;
}
function getdbpassword() {
return $this-dbpassword;
}
function setdbpassword($req_password) {
$this-dbpassword = $req_password;
}
function getsql() {
return $this-sql;
}
function setsql($req_sql) {
$this-sql = $req_sql;
}
function getnumberrows() {
return $this-numberrows;
}
function setnumberrows($req_numberresults) {
$this-numberesults = $req_numberresults;
}
function setdbconnection($req_dbconnection) {
$this-dbconnection = $req_connection;
}
function getdbconnection() {
return $this-dbconnection;
}
function setTransactionSwitch($switch) {
$this-TransactionSwitch = $switch;
}
function getTransactionSwitch() {
return $this-TransactionSwitch;
}
/*
This is the constructor for the object. In this case I have set
the initial values of a number of the object properties to those
values declared in the global constants.inc. By doing this, I
only need to change the values of these properties for specific
operations, which we will not need to do throughout this example
*/
function mysqldb() {
global $HOST, $DB, $WEBUSER, $WEBPASSWORD;
global $TRUE, $FALSE;
$this-sethost($HOST);
$this-setdb($DB);
$this-setdbuser($WEBUSER);
$this-setdbpassword($WEBPASSWORD);
$this-setdbconnection($FALSE);
}
/*
These are the methods for the object. They provide for opening a
connection to the database, closing a connection and executing a
SELECT query. Of course, these can be expanded upon to allow for
INSERT's, UPDATE's and DELETE's etc...
*/
function opendbconnection() {
global $TRUE, $FALSE;
$this-dbconnection = mysql_connect($this-dbhost,
$this-dbuser, $this-dbpassword);
if ($this-dbconnection == $TRUE) {
$this-db = mysql_select_db($this-db);
$this-setdbconnection($TRUE);
} else {
$this-setdbconnection($FALSE);
return false;
}
return true;
}
function closedbconnection() {
if ($this-dbconnection = $TRUE) {
mysql_close($this-dbconnection);
}
}
function begin( ) {
if ($this-dbconnection == $FALSE) {
$this-opendbconnection();
}
$this-setsql(BEGIN);
$this-qry = mysql_query($this-sql);
if (!$this-qry) {
return false;
} else {
return true;
}
}
function rollback( ) {
if ($this-dbconnection == $FALSE) {
$this-opendbconnection();
}
$this-setsql(ROLLBACK);
$this-qry = mysql_query($
Re: [PHP] Classes vs. Functions
ðÒÉ×ÅÔ!
Martin Clifford wrote:
Could someone please explain the difference between classes and functions
and how to use a class.
Well, that's a 1 billion $$ question. I don't think one can fully grasp
that difference by reading an email. I strongly suggest you to buy
yourself a book about OOP and have a go at it. That is, if you really
care about knowing.
Whether you should like OOP or not is a religious matter, so I will not
enter the field. OOP has its pluses and its minuses. It's a technique,
not an ultimate truth, although it is often presented as such. And as
any technique, it can do wonders and it can do plain bull**t when not
properly used.
Nowadays 100% of my work is OOP based, but I worked some 15 years on
functions and I cannot blame those who keep working that way. There are
reasons for doing it and reason for not to do it. Get yourself a good
clear book, then make a decision.
ÐÏËÁ
áÌØÂÅÒÔÏ
ëÉÅ×
-_=}{=_-@-_=}{=_--_=}{=_-@-_=}{=_--_=}{=_-@-_=}{=_--_=}{=_-
LoRd, CaN yOu HeAr Me, LiKe I'm HeArInG yOu?
lOrD i'M sHiNiNg...
YoU kNoW I AlMoSt LoSt My MiNd, BuT nOw I'm HoMe AnD fReE
tHe TeSt, YeS iT iS
ThE tEsT, yEs It Is
tHe TeSt, YeS iT iS
ThE tEsT, yEs It Is...
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] Classes vs. Functions
Martin Clifford wrote: Could someone please explain the difference between classes and functions and how to use a class. Whether you should like OOP or not is a religious matter, so I will not enter the field. OOP has its pluses and its minuses. It's a technique, not an ultimate truth, although it is often presented as such. And as any technique, it can do wonders and it can do plain bull**t when not properly used. Nowadays 100% of my work is OOP based, but I worked some 15 years on functions and I cannot blame those who keep working that way. There are reasons for doing it and reason for not to do it. Get yourself a good clear book, then make a decision. [snip] I have to agree here. IMO, there are benefits in using classes over functions, and there's benefits in using functions over classes. Once you get to know oop a little better, you should be able to determine which is better is any given situation. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Classes vs. Functions
On 17 Jul 2002 at 12:43, Michael Hall wrote: There is no simple answer here. I have started using classes where I find I am writing a lot of related functions that share similar parameters. Database connection and queries are a good example. Authentication is another. Yeah. I have another class that builds forms, because I just hate the tedium of coding HTML forms by hand. It is really just a collection of functions, though, and could work fine as such. This is a gray area imho. I'd leave all html to the person who cares what it looks like, not what it does. I usually also use a code generator to create html and their forms but they are a separate layer. I use templates, wish a lot more php people would as well although I've seen some weird stuff where in this one bb they store templates in the database. That's interesting. I'm still learning/exploring ... I am always guided by the principle that whatever makes less work for me (but achieves the same result) is probably a good thing. IMHO classes are best for more universal code that really can be used in many different places. My functions tend to be more application specific. Yeah, can't say too much more than that. There is the style of coding where one application is completely independent of another. Then you begin to realize, gee ... I could just cut and paste this code. And then there's always the funny repetion of the exact same code every 30 lines or so (depending on memory of programmer I guesss). Eventually you begin to realize gee ... could I put this stuff in a library. A CLASS after all is just a collection of functions with a data model. But ... there is modular and then there is OO imho. I'm a die hard modular programmer who is trying to think in a more OO way. But of course when you just gotta get something done, do it. The value in spending a bit more time going the modular/OO route is that your application will be easier to evolve and debug. Peter-- http://www.readbrazil.com/ Answering Your Questions About Brazil -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] Classes vs. Functions
[snip] A CLASS after all is just a collection of functions with a data model. But ... there is modular and then there is OO imho. [snip] A class is more than just a bunch of functions that have been placed together. If you want to do that, then you might as well just throw them all into the same include file and that's it. There's no added benefit in wrapping a class around them. Agreed, a class can be used to simulate the C-style struct, or to collect a bunch of functions, but the real power of classes is when you start to model the real world objects (ie, methods and properties, not just functions and variables.) I'm not saying to go all OO (or all procedule, I use both...), just that when used correctly, they can be really helpful. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
