OO Classes and MySQL

madhavr

im currently working on something using normal straightforward procedural php and mysql.

i have been thinking about using OO but i am struggling to see how OO will work with mysql in terms of how things are represented.

at the moment i just work with data from the database which is fine. what i think OO requires me to do is to read the data from the databse put it into an object and then use that object when doing the data manipulation etc. im not sure if im right.

for those that dont get what i am saying let me give an example ....

say we have a table called account which contains account details for a customer. in a procedural world we might just read and manipulate the data as required without too much fuss. in OO terms i think i need to create an instance of the class Account then feed the relevent data from the database into this instance.

what i think this would mean is alot of creating of objects when working with data and destroying of objects once the data from the instance has been update into the database.

i need someone to really help me clarify this understanding because at the moment it looks alot of hard work to me. dont get me wrong i know there are obvious advantages to OO like inheritance but the work to get data back and forth from object to database seems much.

anyway let me know what you people think. thanks.

saronoff

Basically, if you're doing a lot of passing via URL or using sessions, classes can work to encapsulate all the data into one object so its easier to pass, store in a cookie, or store in a session variable.

However, if you're only using data and then throwing it away because you won't need it again then classes don't really make sense for you. You'd be better off writing some functions that manipulate data and leave the classes out for now.

For the most part OO is the way to go but in a lot of cases it just adds overhead and headache.

If you've deemed it necessary to use classes you will need to figure out your data members and your member functions. Data members usually correspond, in a database environment, to the columns in the database. Member functions are just functions that operate on the data stored in the class.

PHP.net is a good reference for OO in PHP and there are some good books on the subject if you want to look more into it.

NeonZ

Check out the article at http://www.zend.com/zend/art/mistake1.php

There's a section that talks about OO. Though the article could be considered old, the technology discussion should still be valid.

--MartinZ

shmert

I've just finished writing 2 separate database persistence layers. One in java, one in PHP. Once you get over the initial works of creating the class, it can really simplify working with the database, and provide some really nice consistent functionality.

Here's a rough framework for a simpler persistence layer. I maybe got a little carried away writing this, better just send it before I do anything else...

madhavr

hi guys thanks for the response. i guess my problem is that i started out with a small project with designs drawn up in uml class diagrams but i find myself questioning the use of OO at all. but am wondering whether UML was necessary at all.

i have used ERDs for the database design which makes sense but am not sure about the representation of entities in OO php.