SQL & PL/SQL :: Name Of Primary Key Constraint Is ID_PK

I have a table say EMP with 2 fields ID and Name, with ID being the primary key. The name of the primary key constraint is ID_PK.Now my scenario is :

1. Rename the table EMP to EMP_TEMP;
2. Create an empty table EMP
3. If (data successfully loaded into EMP)
{
Drop EMP_TEMP;
}
else
{
Drop EMP;
Rename EMP_TEMP to EMP;
}

The problem here for me is the primary key constraint. When I am in 2, I cannot create the primary key constraint again since the old one is still in tact. If I go ahead to drop the original pk constraint and re-create a new one in 2, then in case of else part , I need to get the constraint again while renaming the original table.