How can we hard delete a record using a Apex class/by code in salesforce?

Hi,

Hard delete is done by using DataBase.emptyRecycleBin method in the Batch class. Create a sample Batch class as mentioned below and use DataBase.emptyRecycleBin method in the Batch class.

global class BatchDeletion implements Database.Batchable<sObject>, Schedulable 
{ 
global BatchDeletion()
{
//constuctor 
}

global Database.QueryLocator start(Database.BatchableContext bc)
{
//query to return all expired Case Share records 
return Database.getQueryLocator([Select id from Account where Name=’Test Account12′]);
}

global void execute(SchedulableContext sc) 
{ 
//execute the batch
BatchDeletion deleteCS = new BatchDeletion();
ID batchprocessid = Database.executeBatch(deleteCS);
}

global void execute(Database.BatchableContext BC, list<sObject> scope)
{ 
System.debug(‘## deleting ‘+scope.size()+’ case share recs’);

//delete list of expired Case Share records
delete scope; 
Database.emptyRecycleBin(scope); 
}

global void finish(Database.BatchableContext BC) 
{ 
//no post processing
/* System.debug(‘## Batch Job Finished ##’);
UpdateAccountFields m = new UpdateAccountFields ();
String sch = ’20 30 8 10 2 ?’;
system.schedule(‘Merge Job’, sch, m);*/

}
}

Hope this helps.