hi

Finally i am replying to my own  post 

1) Datamodel Vs Datamapping
 
LDM and PDM means Logical Data Model and Physical Datamodel. LDM is at the manager and above  level which contains the detailed pictures of the tables, their columns (Ex Emplyee Identification Number) and how they are connected to each other.PDM is at the lower level which contains the tables and their columns in a short form(ex:Emp_Id),their datatypes and not null/null condition. Both of them are pertaining to the database.

2) Data mapping can be explained with the following example:
For Ex: Say we have two tables. Department with columns Dept_Id,Dept_Name and Employee with columns Emp_Id,Emp_Name and Dept_Id.
This is pertaining to ETL not reporting. From source, when we are loading these to the target, which column is matching to what is called data mapping. First,Department table has to be feeded, then employee table. So, the source needs to map with the Dept_ID column in the Department table and the same Dept_ID should be mapped to the one in the employee table. Because both of them should be same. Hope i am clear. In case of any questions, please shoot them unhesistantly.

Thanks & Regards
Sowjanya