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Explain view in RDBMS?
View - A view is a relation (virtual rather than base) and could be used in query expressions, which is, queries can be written by using the view as a relation. Instead, a view is a named table in which is represented, not through its own physically separate stored data, but through its definition in terms of other named tables (base tables or views). The base relations on that a view is based are sometimes known as the existing relations. The definition of a view in a create view statement is stored within the system catalog. The syntax to create a view is:
CREATE [OR REPLACE] VIEW [()] AS
WITH {READ ONLY|CHECK OPTION [CONSTRAINT
]};
Describe the Composite Key Composite Key: Sometimes one key is not enough to uniquely recognize a row. E.g. in a single class Roll is enough to search a student, but in the w
How does a query tree represent a relational algebra expression? Ans: This includes transforming an initial expression (tree) into an equivalent expression (tree) that is
What is system catalog or catalog relation? How is better known as? A RDBMS maintains a explanation of all the data that it contains, information about every relation and index
Define multivalued dependency and 4NF. Ans: Multivalued Dependency - Assume R be a relation schema and let α ⊆ R and β ⊆ R. The multivalued dependency α →→β holds o
Examine about the Behavioural Diagrams The main objective of behavioural diagrams is to visualize, specify, construct and document dynamic aspects of a system. The interactio
State the Object Design for Processing The object design phase comes after analysis and system design phase. The object design phase includes implementation details like as i
the of super market system done in database
Which method of access uses key transformation? A Hash method of access uses key transformation.
Explain Data Sublangauges ? Data sublanguage: In relational database theory, the term sublanguage, first used for this purpose through E. F. Codd in the year of 1970, refers t
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