Hi 

Can anyone help me in converting this trigger into calling a batch class.

As it is not sufficient for our bulk loading of 4 millions data.

Here is the trigger:

trigger createacc on Contact (after insert) {
list<Contact > con=[select id,firstname ,lastname from contact where id in:Trigger.newMap.keySet()];
list<account >acc =new list<account>();
list<contact>cc1 =new list<contact>();
for(contact c : con)
{
account a =new account ();

a.name =  c.FirstName != null ? c.FirstName + ' ' + c.LastName : c.LastName;
acc.add(a);

}
insert acc;
for(account a1:acc){
system.debug('---------------------this is id --------------------'+a1.id);
for(contact c : con){
c.accountid=a1.id;
cc1.add(c);
}
}
update cc1;
}

I have a format please update me exact correct code works for my scenario:

trigger insertAccount on Contact (after insert) {
Map<id, Contact> contacts = new Map<id, Contact>();
for (Integer i=0;i<Trigger.new.size();i++) {

contacts.put(Trigger.new[i].Id, Trigger.new[i]);

}
// You can execute batch apex using trigger using below codes
if (contacts.size() > 0) {
Database.executeBatch(new InsertAccounts(contacts));
}
}

global class InsertAccounts implements Database.Batchable<sObject> {
//map of contactid - contact
Map<Id, Contact> contactMap = new Map<Id, Contact>();
global InsertAccounts(Map<Id, Contact> contacts) {
ContactMap = contacts;
}
global Database.QueryLocator start(Database.BatchableContext BC) {
return DataBase.getQueryLocator([SELECT Id,FirstName, LastName,AccountId FROM Contact WHERE accountID IN : contactMap.keySet()]);
}
global void execute(Database.BatchableContext BC,List<Account> scopeAcc) {

for (Integer i=0;i<scopeAcc.size();i++){
scopeAcc.get(i).Area__c=ownerMap.get(scopeAcc.get(i).OwnerId).Team__c;
}
update scopeAcc;
}
global void finish(Database.BatchableContext BC) {
//Send an email to the User after your batch completes
Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
String[] toAddresses = new String[] {'info@theblogreaders.com'};
mail.setToAddresses(toAddresses);
mail.setSubject('Apex Batch Job is done');
mail.setPlainTextBody('The batch Apex Job Processed Successfully');
Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });
}
}