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Explain Domain calculus
Domain calculus is one of the types of the relational calculus. The formal specification of the domain calculus was planned after the development of the QBE system. Domain calculus has the variables range in excess of single value from domains of attributes. To create a relation degree n for a query result, we should have n domain variables - one for each attribute. An expression of the domain calculus is of the form {X | F(X)}
In which F is a formula on X and X denotes a set of domain variables. The expression characterizes X like F(X) is true.
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Views in relational algebra: 1. Basic expression contains either a) A relation in the database. b) A constant relation. 2. General expressions are madde out of sma
difference between internal schema and external schema in DBMS
In an E-R diagram an entity set is represent by? In an E-R digram entity set is represted by rectangle.
Which is an advantage of view? The Advantages of view is Data security, Derived columns and Hiding of complex queries
These are interactive interfaces, graphical that hide the difficulty of the DBMS and query language behind an intuitive, simple to understand, and convenient interface. This permit
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Natural Join : It is the similar like Equi join except one of the duplicate columns is removed in the result table. The natural join is the most usually used form of join operation
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