Explain projection operation distribute over union operation, Database Management System

Assignment Help:

Illustrate the statement 'Projection operation distributes over the union operation'. Give an example.   

Ans: ΠL(E1 ∪ E2) = (ΠL(E1)) ∪ (ΠL(E2))  

This says that result acquired by projecting on an attribute set A, after taking union of two relations is similar as union of two relations each of which is a projection of original relations on A.


Related Discussions:- Explain projection operation distribute over union operation

State about the advance object design, ADVANCE OBJECT DESIGN Introduct...

ADVANCE OBJECT DESIGN Introduction Analysis is the initial step of the OMT methodology. It is apprehensive with devising a precise, concise, correct and understandable mo

Define the boyce-codd normal form, Define the Boyce-Codd Normal Form with i...

Define the Boyce-Codd Normal Form with instance and also Compare BCNF and 3NF.  Ans: BCNF: For each functional dependency X->Y in a set F of functional dependencies over relati

Relationship between two tables-strategic decision making, In a job intervi...

In a job interview with a branch manager of a bank that operates in multiple Canadian provinces and the Yukon, you learn that all of the information is captured in real time in a s

Relational operations, Let us now talk about the relational operations: ...

Let us now talk about the relational operations: SELECT The select operation is used to select few specific record from the database based on different criteria, This is a un

What are the storage types, What are the storage types? The storage typ...

What are the storage types? The storage types are: a) Volatile storage b) Nonvolatile storage

Define redo logs, Redo Logs: Any database must have minimum two redo logs....

Redo Logs: Any database must have minimum two redo logs. These are the rules for the database; the redo logs record all modifies to the system objects or user objects. If any type

Incident report to the database, The Form input elements are:           ...

The Form input elements are:             Reporter name                                                text type input             Password

Division operation, To do the division operation R1 ÷ R2, R2 should be a co...

To do the division operation R1 ÷ R2, R2 should be a correct subset of R1. In the following example R1 have attributes A and B and R2 have only attribute B so R2 is a correct subse

Define thomas write rule, Define Thomas write rule Thomas' write rule: ...

Define Thomas write rule Thomas' write rule: The Thomas' write rule is a modification of timestamp-ordering protocol for concurrency control. Assume that transaction T i issue

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd