Question - What is a lookup table in database? where can we use these type of table?
Answer -
Lookup tables are like constraints which hold a value. The content in the lookup tables dosen't change often, hence refered as lookup (reference).
Example : Countries table
Countries are not added on regular bases hence one can consider the table as a lookup table. As and when needed in some other table the countries information can be fetched base on PK - Country-Code column. Eg - Emp_Per_Info.