Thanks.

For SET PF-STATUS check out this link: Dialog Status for Lists

It says:

You set the dialog status for lists in the same way as for normal screens, that is, using the statement

SET PF-STATUS [EXCLUDING |]
[OF PROGRAM ]
[IMMEDIATELY].

This statement sets the status for the current output list. The dialog status must be defined for the current program, unless you have used the OF PROGRAM addition to set a status from another program . The status is active for all subsequent list levels until you set another status. The SY-PFKEY system field always contains the status of the current list.

Using SET PF-STATUS, you can display different user interfaces for different list levels to provide the user with different functions according to the individual requirements. Use SET PF-STATUS SPACE to set the standard list status. This depends on the event blocks in the program, as described above.

The EXCLUDING option allows you to change the appearance and available functions of a status from within the program. This is useful if the individual user interfaces for a range of list levels are very similar. You can define a single global status, and then just deactivate the functions you do not need using EXCLUDING. Specify to deactivate the function code stored in field . Specify to deactivate all function codes stored in the internal table . Field and the lines of table should be defined with reference to the system field SY-UCOMM.

The IMMEDIATELY addition is intended specially for list processing. You use it while creating a detail list within an event block to change the status of the list currently displayed (index SY-LISTI). Without this option, the system changes the status of the current secondary list (SY-LSIND) that is displayed only at the end of the processing block.

For Logical Database check out this link: Using Logical Databases

Don’t think Logical Databases look like real databases. They are just prewritten and ready-to-use database selection programs which can be used with an executable ABAP program. Instead of using complex SELECT statements in your program, if one exists, you can use a logical database.