Example of separated storage and logic

Database.sol

contract Database{
    mapping(uint => uint) public _data;
    mapping(address => bool) _owners;
    
    function Database(address[] owners){   //Called once at creation, pass in initial owners
        for(uint i; i<owners.length; i++){
            _owners[owners[i]]=true;
        }
    }
    
    function setData(uint id, uint data) public returns (bool){
        if(_owners[msg.sender]){
            _data[id] = data;
            return true;
        }
        
        return false;
    }
    
    function changeOwners(address owner, bool permission) public returns(bool){
        if(_owners[msg.sender]){
            _owners[owner] = permission;
            return true;
        }
        
        return false;
    }
}

example.js

var owners = [eth.accounts[0]];/* Initial owners*/ ;

/* First time - initialize the database  */

var databaseContract = web3.eth.contract([{"constant":true,"inputs":[{"name":"","type":"uint256"}],"name":"_data","outputs":[{"name":"","type":"uint256"}],"type":"function"},{"constant":false,"inputs":[{"name":"id","type":"uint256"},{"name":"data","type":"uint256"}],"name":"setData","outputs":[{"name":"","type":"bool"}],"type":"function"},{"constant":false,"inputs":[{"name":"owner","type":"address"},{"name":"permission","type":"bool"}],"name":"changeOwners","outputs":[{"name":"","type":"bool"}],"type":"function"},{"inputs":[{"name":"owners","type":"address[]"}],"type":"constructor"}]);
var database = databaseContract.new(
   owners,
   {
     from: web3.eth.accounts[0], 
     data: '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', 
     gas: 1000000
   }
 )
 
 /* --------------- To add logic contracts ----------------- */
 
 var data = database.address; /* Address of database */ ;

var logicContract = web3.eth.contract([{"constant":false,"inputs":[{"name":"newContract","type":"address"}],"name":"update","outputs":[],"type":"function"},{"constant":false,"inputs":[],"name":"example","outputs":[],"type":"function"},{"inputs":[{"name":"data","type":"address"}],"type":"constructor"}]);
var logic = logicContract.new(
   data, // This is where the address gets passed in
   {
     from: web3.eth.accounts[0], 
     data: '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', 
     gas: 1000000
   })
   
   // To update the permissions in the database (first wait for logic to be mined)
   database.changeOwners(logic.address, true,{from:eth.accounts[0],gas:100000});
   
   //Or if there already is a logic contract
   oldLogic.update(logic.address, {from:eth.accounts[0],gas:100000});
   
   

Logic.sol

contract Database{
    function _data(uint id) public constant returns (uint data);
    function setData(uint id, uint data) public returns (bool);
    function changeOwners(address owner, bool permission) public returns(bool);
}

contract Logic{
    Database database;
    
    function Logic (address data){
        database = Database(data);
    }
    
    // Logic here
    
    function update(address newContract) public {
        database.changeOwners(newContract,true); // Give new contract write permissions
        database.changeOwners(this,false); // Revokes it's own permissions 
    }
    
    function example(){
        uint foo = database._data(1337); // get data
        database.setData(1337,1234); // set data
    }
}

I am wondering, what's the difference between the two Database contracts, and why do you define it twice?

edit, nevermind, rereading everything sometimes help.