Define the concept of aggregation, Database Management System

Assignment Help:

Define the concept of aggregation.  Give two examples where this concept is useful.

Ans: Aggregation transforms a relationship among the objects into a higher-level object. A new data type known as aggregate is developed which, under specific criteria of "well-definedness," defines aggregation abstractions. Relational databases illustrated as collections of aggregates are structured like a hierarchy of n-ary relations. To keep well-definedness, update operations on such type of databases must keep two invariants. Well-defined relations are different from relations in third normal form. It is displayed that these notions are complementary and both are significant in database design. A top-down method for database design is described that separates decisions concerning aggregate structure from decisions concerning key identification. It is suggested that aggregate types, and other sorts which support real-world abstractions with no introducing Key identification.


Related Discussions:- Define the concept of aggregation

Natural join-table handling, Natural Join : It is the similar like Equi joi...

Natural Join : It is the similar like Equi join except one of the duplicate columns is removed in the result table. The natural join is the most usually used form of join operation

Database tables design and test queries, Load sample data into the database...

Load sample data into the database tables design and test queries to return the following information • All rows and columns for employees • All rows and columns for customers •

Query optimization in database system, Problem : AirwaysCentre, an inte...

Problem : AirwaysCentre, an international airline booking company currently uses a relational database system for their operations, which includes the following relations: P

What are the benefits of prepared statements, What are the benefits of prep...

What are the benefits of prepared statements and place holders? Parameter binding operations automatically handle escaping of characters Encourage Statement reuse

Oracle, comparison of oracle RDBMS with MySQL

comparison of oracle RDBMS with MySQL

Benefits abd drawback of hashed file organisation, Benefits of Hashed file ...

Benefits of Hashed file Organisation 1.      Insertion or search on hash-key is quick. 2.      Best if equality search is required on hash-key. Drawbacks of Hashed file

Describe hashing in dbms, Describe Hashing in DBMS? Hashing: Hashing ...

Describe Hashing in DBMS? Hashing: Hashing is a technique to store data within an array so which storing, searching, inserting and deleting data is fast (in theory it's O(1))

Express the properties of strings, Express the properties of Strings? ...

Express the properties of Strings? Strings can be case sensitive (or not) which can change the outcome of string operations. You can evaluate whole strings \ just part

Sql, Events4Fun is an event management company in Europe with branches in S...

Events4Fun is an event management company in Europe with branches in South America as well. The company is well-known for its efficiency, good-quality services, and affordable char

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