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!
Set Difference
If R1 and R2 are two union compatible relations or relations then result of R3 =R1- R2 is the relation that have only those tuples that are in R1 but not in R2.
Incase, R3 will have tuples such that R3 = {t | R1 ∋ t ∧ t∉R2}.
Example:
R1
X
Y
A1
B1
A7
B7
A2
B2
A4
B4
R2
A
B
A3
B3
R1-R2 =
R2-R1=
Note: -1) Difference operation is not commutative, i.e.,
R1 - R2 ≠ R2 - R1
2) Difference operation is not associative, i. e.,
R1 - (R2 - R3) ≠ (R1 - R2) - R3
Define Aggregate functions and what aggregate functions supported by the MySQL To calculate a summary value from a set of individual values and uses one of the functions known
What is a SELECT operation? The select operation selects tuples that please a given predicate. We use the lowercase letter σ to denote selection.
We are looking to find someone to prepare a database which improves upon the one we are using at present. The present database will be found here: Click on filter options and yo
For the question given below, you are required to submit design and implementation documentation as described over the page. Design, implement (in Java), test and document a set of
Describe the algorithm to draw the dependency graph? Ans: Algorithm to draw Precedence Graph is like this: a. For every transaction T i participating in schedule S, make
A B-tree of order how much children m has maximum ? m has maximum m mchildren in a B tree.
what factors might influence a company to outsource its IT infrascture.
What does the extract statement do in extract datasets? The data is written to virtual memory by extract commands.
Write a short note on QBE? Stands for "Query By Example." QBE is a feature involved along with various database applications which gives user-friendly techniques of running da
What are aggregate functions? And list the aggregate functions supported by SQL? Aggregate functions are functions that take a collection of values as input and return a one va
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: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd