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
Let consider the given partial relation EMP. Let us make some sub-queries for them EMPNO ENAME JOB SAL DEPTNO 7566
What are the types of reference?explain it with suitable examples? Object oriented language given the ability to refer the object attribute of the type can be referred to the s
Can a domain, assigned to a data element be changed? Yes. We can do so by just overwriting the entry in the field domain.
What is a records management consultation? Our organization is an authority for disseminating your specific requirements and giving you with a solution to effectively manage yo
What is the use of Union and intersection operation? Union: The result of this operation contains all tuples that are either in r1 or in r2 or in both r1 and r2.Duplicate tuple
Do the 11.1 11.1 Credit Card Use. Consider the following hypothetical bank data on consumers’ use of credit card credit facilities in Table 11.3. Create a small worksheet in Exce
What are the advantages of creating a table from existing table?
What is a relationship called when it is maintained between two entities? A relationship is called Binary relationship when it is maintained between two entities.
Illustrate the view of software architecture A model is a semantically closed abstraction of system composes of elements. It can be visualized using any of the following five v
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
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