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What is meant by heuristic optimisation? Discuss the main heuristics that are applied during query optimisation.
Ans: In heuristic optimization, heuristics are employed to reduce the cost of optimization in place of analyzing the number of different plans to make out the optimal plan. For instance, a heuristic optimizer would make use of the rule 'Perform selection operation as early as possible' without finding out whether the cost is reduced by this transformation. Heuristics approach generally assists to reduce the cost but not all the time. The major heuristics that are applied throughout query optimization are:
Removing a Synonym: DROP SYNONYM D30;
Before defines the second type of integrity constraint, viz., Entity Integrity, we should be well-known with the concept of NULL. Mostly, NULL is intended as a basis for dealing
a need some real life examples of database management systems three level of ANSI SPARC architecture life teacher and student ,company and employee or for NGO etc.
Creating views with Replace option : This option is used to alter the definition of the view without recreating and dropping it or regranting object privileges previously granted o
What is Message switching Message switching transmits data units which can be arbitrarily long. Packet switching has a utmost packet size, if any message longer than that, it s
For your chosen project, you need to identify the current problem that you wish your project to solve. Produce a Problem Statement. The Problem Statement should explain the purpo
What is known as heap file organization? In the heap file organization, any record can be placed anywhere in the file where there is space for the record. There is no ordering
The definition of the classes and operation can often be adjusted to increase the amount of inheritance". Justify the above statement. Adjustment of Inheritance The def
Physical Database Design Issues The database design includes the process of logical design with the use of E-R diagram, normalisation, etc., followed by the physical design.
What is a hash index? A hash index organizes the search keys, with their associated pointers, into a hash file structure.
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