Define union compatibility, Database Management System

Assignment Help:

Define union compatibility? Explain why INTERSECTION of two relations cannot be performed if they are not union compatible?

Two relations R(A1, A2,-------, An) and S(B1, B2,-----, Bn) are said t union compatible if they have the similar degree n and if dom (A) = dom(B) for all i=1---ni i Intersection needs two relations to be union compatible since or else it is not probable to formulate the criterion as to on what basis will attributes be considered as general.


Related Discussions:- Define union compatibility

Write query to select student from math department, Consider the table stud...

Consider the table student and list names of students in the departments other than maths and computer. SELECT std_name FRM student WHERE dept_name NOT IN (‘Maths','Computer);

Database incident table, The Incident table, with an auto-incrementing in...

The Incident table, with an auto-incrementing incident number, etc, looks like: incident_num reporter date time incide

Developer competent in data cleansing-data scrubbing, Data Scrubbing 70,000...

Data Scrubbing 70,000 records Project Description: We need services of a developer competent in data cleansing/Data scrubbing. Scope: - 70,000 records in CSV format.

What are the ways of obtaining the connection parameters, What are the ways...

What are the ways of obtaining the connection parameters?  Hardwire the parameters into the program. Ask for the parameters interactively. Get the parameters

Define transitive dependencies, What do you understand by transitive depend...

What do you understand by transitive dependencies? Define with an example any two problems that can take place in the database if transitive dependencies are available in the datab

What is E-R model, E-R Model This data model is based on real world th...

E-R Model This data model is based on real world that consists of basic objects named entities and of relationship among these objects. Entities are illustrated in a database

design the logic using looping structure, 1. Design the logic, using a loo...

1. Design the logic, using a looping structure, for a program that outputs every even number from 1 through 25 along with its square and cube. 2. Mr. Sanchez owns 12 apartme

What is database files , The database files accept the actual data and ...

The database files accept the actual data and are typically the biggest in size. Depending on their shape, the tables for all the user operation can go in one database file-but

Mention the various user privileges, Mention the various user privileges ...

Mention the various user privileges All privileges directly granted to the user or role. All privileges granted to roles that have been granted to the user or role.

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