Hi Sriram,
Time Constraint 1 and 2, more or less, behaves the same way...
Below self explanatory SAP help text can help..
For the entire time that the employee works at the enterprise, exactly one valid infotype record must exist. The validity periods of the individual records must not overlap. If a new record is created, the system automatically uses the start date of the new record as the delimitation date of the old record. Gaps are only allowed between the employee’s entry date and the start date of the first record.Time constraint 1 must be used for all of the infotypes containing information that must be available at all times. This is particularly true of personal and organizational assignment data.If a record is delimited because of time constraint 1, the system displays an appropriate message.
No more than one valid record can exist at any one time. Records with constraint 2 must not overlap. Their existence is not obligatory. If a new record is created, the system automatically delimits the previous record, if one exists.
If a record is delimited because of time constraint 2, the system displays an appropriate message.
Hope this helps.
Regards
Kumarpal