Questions

A relational database is a digital database based on the relational model of data, a database structured to recognize relations between stored items of information. A software system used to maintain relational databases is a relational database management system.

Computer database in which all data is stored in Relations which (to the user) are tables with rows and columns. Each table is composed of records (called Tuples) and each record is identified by a field (attribute) containing a unique value. Every table shares at least one field with another table in 'one to one,' 'one to many,' or 'many to many' relationships. These relationships allow the database user to access the data in almost an unlimited number of ways, and to combine the tables as building blocks to create complex and very large databases.

a -  at the peak of changes in blood pressure indicates the systiolic pressure.

Wherever on earth we hold a compass, the needle points towards the magnetic North Pole. A compass is a great tool for navigation.

Compass is widely used in aircrafts, ships, military services,...