Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Define the Query optimisation
The query parser commonly generates a standard initial tree to correspond to an SQL query, with no doing any optimization. Such type of a canonical query tree denotes a relational algebra expression that is extremely inefficient if executed directly. A query commonly has many possible execution strategies, and the process of choosing a appropriate one for processing a query is termed as query optimization. The major guidelines that are applied throughout query optimization are:
a. Combine a cascade of selections
b. Combine a cascade of projections
c. Commute selection and projection
d. Commuting selection with join / cartesian product Commuting projection with join or cartesian product
e. Commute projection with set operations
f. Commute selection with set operations
What are the advantages of creating a table from existing table?
State as Location within a Program In this traditional approach, location of control inside a program totally defines the program state. Any finite state machine may be implem
What is a transaction ? The Transaction is a unit of data processing. For instance, many of the transactions at a bank may be withdrawal or deposit of money; transfer of money f
Give the forms of triggers? The triggering event can be insert or delete. For updated the trigger can state columns. The referencing old row as clause The referencing
What is Nested Trigger? A trigger can also having INSERT, UPDATE and DELETE logic within itself, so when the trigger is fired because of data modification it can also cause ano
Write a short note on built in function in QBE? Built in function in QBE: QBE involves various built in functions like AVG, MAX,MIN,SUM and CNT. We must prefix these operator
wrie a report on whether a BSc n information systems develops the skills required by employers in Database administration
Higher Normal Forms Is there more normal forms beyond BCNF? Yes, though, these normal forms are not based on the concept of functional dependence. More normalisation is needed if
What is data model? Explain object based and record based data models? Ans: A data model is an abstract model in which describes how data is represented and accessed. (i)
What are the functions of an accumulator? The accumulator is the register associated with the ALU operations and sometimes I/O operations. It is an integral part of ALU. It hol
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd