Should I instantiate new objects for all different interactions?

Question

Im having a hard time grasping this concepts of objects and how they should interact/exist.

Should I for instance have different objects (well, maybee I mean connections to the database here if there is any difference) for interactions with my database whenever they are not related?

Lets say I have one object that index.php uses to get and display content from the database and another object that a user use to add/remove things in the database. We can say that the objects are all of the class dbinteract which holds all the functions for messing about with the database.

Or should I maybee divide the classes into something like: dbconnection, dbdisplay, dbinsertion, dbmodification where I send the dbconnection to the other objects?

I feel like im missing something very obvious and it's frustrating trying to move forward not knowing where in the thought process im going wrong, I guess im looking for a question as well as a an answer here.

index.php

$connection = new dbconnection();
$displayer = new dbdisplay();

$activeconnection = $connection->connecttodatabase();
$pagetodisplay = $connection->getcontentofpagetodisplay($query);
$displayer->displayPage($activeconnection, $pagetodisplay);

userinsert.php

$inserter = new dbinsert();
$usersdbconnection = new dbconnection();

$inserter->newPost($userdbconnection, $usercredentials, $posttextfromuser);
$usersdbconnection->closedatabaseconnection();

Answer 1

To me, what it seems like you're missing is that object-oriented programming isn't there to make you do extra work following its rules, it's there to make your life easier. If it isn't making your life easier, you're doing it wrong.

Answer 2

sometimes books are better then surfing the net i found this book really useful. the examples lean towards java, but can be applied to any language

http://oreilly.com/catalog/9780596008673/

Answer 3

You seem to be think at the wrong level of abstraction. OOP allows you to think about 'users' and 'articles' instead of 'database connections' and 'pages'.

I'm not sure I understand the problem fully - I think your question is 'which object should be responsible for connecting to the database?'. Creating a connection to the database only needs to be done once. This connection can then be shared between all of the objects. To share the connection you will need to create a class which all other classes that connect to the database can inherit from and a static variable in that class to ensure that only one connection object exists.

In other languages static variables are commonly called class variables.