any batch apex scenarios in Salesforce?

Hello Uppada kishore,

We use batch apex for bulk processing. Let's say you want to update thousands to accounts on a regular basis or (even if just one time) and real time update is not a MUST HAVE requirement. You know how you are bound by governor limits for all the retrievals , updates , inserts.

Batch class has much wider governor limits . Its an async operation and you can run a nightliy job and process all these records without hitting limits.

Examples :
I used batch class for a scenario where I had to send email to all contract owners 15 days before payment due date. There were thousands of contracts and at one time there could be many contract owners meeting this criteria. Also, apart from sending email, I had to update a flag on contract. So, I schedules a daily nightly batch job for this.