Q: What are logical databases? What are the advantages/disadvantages of logical databases?

A: LDB consists of logically related tables grouped together – used for reading and processing data.
Advantages

No need of programming for retrieval , meaning for data selection
Easy to use standard user interface, have check completeness of user input.
Disadvantages Fast in case of lesser no. of tables But if the table is in the lowest level of hierarchy, all upper level tables should be read so performance is slower.