How to write batch apex?

Question

I am new to Salesforce. So a help is required from you guyz.

I want to write a Batch Apex, where I want to update some value of Account (lets say Name).

and then from before trigger I have to call this Batch.

How to achieve this??

A help would be very appreciable.

Batch I have written so far

   global class AccUpdate implements Database.batchable<sObject>{ 

   global Database.QueryLocator start(Database.BatchableContext bc) {
    return Database.getQueryLocator('SELECT Id FROM Account');
   }

   global void execute(Database.BatchableContext bc, List<Account> scope) {
       List<Account> Scope1 = [SELECT Id, Name FROM Account];
       for(Account a : scope1){ 
           a.Name = 'Demo Account1'; 
           Scope1.add(a); 
       } 
       update Scope1; 
   }     
   global void finish(Database.BatchableContext info){     
   } 
}

Now I want to write a before trigger and I want to call this batch .

How to do that??

Answer 1

There are many documents available online. few of things are:

http://blogs.developerforce.com/engineering/2013/02/force-com-batch-apex-and-large-data-volumes.html

http://www.salesforce.com/us/developer/docs/apexcode/Content/apex_batch_interface.htm