State the two-way associations, Database Management System

Assignment Help:

Two-way Associations

Mostly, associations are travel in both directions, although not usually with same frequency. There are three approaches for the implementation.

  • In bi-directional associations, if one direction association is seldom used, then we should implement it as unidirectional association. Searching can perform reverse association. This way, we can reduce storage and update cost.
  • Implementing it as a bi-directional association using the several techniques discussed in previous sections will turn up as shown in Figure. This approach provides faster access but also requires updating of other attributes in case of any change otherwise the link will become inconsistent.

Implementing it as a separate association object, i.e., independent of any class as shown in Figure. The association object can be implemented using two objects: one in forward direction and the other one in the reverse direction. This cause increases efficiency when hashing is used, instead of attribute pointer.

 

584_two way association.png

  Figure:  Implementation of association as an object


Related Discussions:- State the two-way associations

Apriori algorithm-find all frequent large itemsets, Your friend owns a comp...

Your friend owns a computer store in Yuen Long, selling Desktop and Notebook PCs and other computer peripherals. Having been rather successful with his business there, he decided t

Describe the concept of aggregation, Aggregation Aggregation is strong...

Aggregation Aggregation is stronger form of association. It represents the "has-a" or "part-of" relationship. An aggregation association depicts a complex object which is comp

Reasons for the growing popularity of data mining, Question: Data Minin...

Question: Data Mining is the process of extracting knowledge hidden from large volumes of raw data. (a) Using a suitable example, illustrate how Data Mining can be useful t

Nested relational model, what is Nested relational model? Explain with exam...

what is Nested relational model? Explain with examples.

Client server databases, Client Server Databases- The concept behind the C...

Client Server Databases- The concept behind the Client/Server systems is simultaneous, cooperative processing. It is an approach that presents a one systems view from a user's vie

Explain in detail about collaboration diagrams, Explain in detail about Col...

Explain in detail about Collaboration Diagrams Collaboration diagrams are interaction diagrams which emphasize structural organisation of an object that transmit and receive m

Create a e-r diagram or uml class diagram, We require an advanced system fo...

We require an advanced system for a Sports Centre, you are concerned only with representing the data discussed below about bookings and members. (The complete system may contain ot

What are the advantages of object oriented databases, What are the advantag...

What are the advantages of object oriented databases in comparison with others? Why it is still not widely used? Object oriented designs are coherent, efficient and less prone

Shared lock or read lock, Shared lock or Read Lock It is requested ...

Shared lock or Read Lock It is requested by a transaction that needs to just read the value of data item. A shared lock on a data item does not permit an exclusive lock

Accessing information permissions users, Accessing information about permis...

Accessing information about permissions to all users- Object level permissions: With the use of data dictionary you can see the permissions to user. Let us get the table name fro

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