(I) Super Key – An attribute or a combination of attribute that is used to identify the records uniquely is known as Super Key. A table can have many Super Keys. E.g. of Super Key ID ID, Name ID, Address ID, Department_ID ID, Salary Name, Address Name, Address, Department_ID So on as any combination which … Read more
Every RDBMS is a DBMS, but the opposite is not true: RDBMS is a DBMS which is based on the relational model, but not every DBMS must be relational. However, since RDBMS are most common, sometimes the term DBMS is used to denote a DBMS which is NOT relational. It depends on the context.
Let’s start with the definition of a wide column database. Its architecture uses (a) persistent, sparse matrix, multi-dimensional mapping (row-value, column-value, and timestamp) in a tabular format meant for massive scalability (over and above the petabyte scale). A relational database is designed to maintain the relationship between the entity and the columns that describe the … Read more