Hi Galeeb :

Let me clear out your queries regarding Batch :

1. Batches are used to perform a certain action on objects when the nuber of records are greater and can not be handled through a script Or if we want to perform a certain action on records after a particulat interval of time.
2. Batch divides the number of records into chunks and perform action accordingly. 
3. In the start method of your batch you will query all the required records related to an Object.In your case you have 200 records.

          Example : Start Method :
          global Database.QueryLocator start(Database.BatchableContext BC){
              return Database.getQueryLocator('Select id from Contact'); //Suppose this query returns 200 revcords.
          }

     4. In Execute Method you will perform the action whic you want to do on the records.

         Example : Execute Method :
        // Execute Logic global
        void execute(Database.BatchableContext BC, List<sObject>scope){
            // Logic to be Executed batch wise
           delete scope;// Suppose you are deleting your records.
         }
     
      5. At last we have finish method which is used to track that whether a batch is run successfully or  not. We can send a mail this method to               the user informing him about the error/success.

Syntax to divide Batch records into chunks.

ExampleBatchClass b = new ExampleBatchClass();
//Parameters of ExecuteBatch(context,BatchSize)
database.executebatch(b,10);

In the above example 10 is the number of records processed in a single chunk.
So if you have 200 records than there will be 20 batches processed.

Since batch is used to perform task in chunks so any which should be commited to Database should be done within the chunks.
If any record in a batch is failed than all the records of that batch is also failed.

Please let me know if you need more information on this.

Regards,
Abhishek