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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
]};
read-set(T) : Each data items that are read by a transaction T Timestamps : for all transaction T, the start-time and the end time are reserved for all the three phases.
Develop a database broker framework to implement a persistence mechanism for the domain objects involved in the use case dealt with in Question 2. a. Specify the attribute type
Determine the rule that a value of a foreign key should appear as a value of some particular table is called a Ans: Referential constraint. The rule that a value of a fo
Primary Key The primary key is the candidate key that is selected by the database designer as the principal denotes of identifying entities within an entity set. The left candi
define locking in simple language and decribed it
what is correlation in nested query
Desirable Properties Of Decomposition Decomposition is a process of dividing a relation into its projections that will not be disjoint. Please remind the Relational projection
education.
One-to-one relationship: For every 1:1 relationship type R in the ER diagram including two entities E1 and E2 we take one of entities (say E1) preferably with total participatio
Define null values. In some cases a certain entity may not have an applicable value for an attribute or if we do not know the value of an attribute for a certain entity. In the
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