[Amarkant]

In developer console , go to open -objects- objectname- select the fields using shift button on keyboard - click on Query button present at the bottom of same screen. You can see query form with all fields in query editor of sales force.

[Amarkant]

Similar to the SQL rollback. Used to rollback the DML Transactions performed on the database in a single transaction sequence.

For more details go through following link    Transaction control in Salesforce

[Amarkant]

MAP<ID,Opportunity> os = new MAP<Id,Opportunity>([Select ID from Opportunity]);
SET<ID> keys = os.keyset();
String s = 'SELECT RecordTypeId, COUNT(Id) os FROM Opportunity Where Id IN ';
s+=':keys GROUP BY RecordTypeId';
AggregateResult[] ars = Database.query(s);
System.debug(ars[0].get('RecordTypeId'));

[Amarkant]

'after undelete' trigger is available in Salesforce but for limited set of objects.

Following is the list of objects on which after undelete will work :

Account
Asset
Campaign
Case
Contact
ContentDocument
Contract
Custom objects
Event
Lead
Opportunity
Product
Solution
Task

The after undelete trigger events only run on top object. For example, if you delete an Account, an Opportunity may also be deleted. When you recover the Account from the Recycle Bin, the Opportunity is also recovered. If there is an after undelete trigger associated with both the Account and the Opportunity, only the Account after undelete trigger event executes.

[Amarkant]

To achieve this you can fetch all the records present in your list view in apex and update that. You will get more help search for StandardSetController methods.

[Amarkant]

Do you want to update the all records present in the object or just the records present in particular list view from which you are clicking the button ?

[Amarkant]

We can have Integer Iterator to achieve this instead of Query Locator in Batch Apex.

[Amarkant]

What is you exact scenario ?

One thing you can do to achieve this, start the next batch in finish method of first batch.

[Amarkant]

In case of junction object, child object always inherits the security settings from his PRIMARY MASTER object. The object included in first master detail relationship is becomes the primary master object.