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

Define shadow paging, Define shadow paging. An alternative to log-based...

Define shadow paging. An alternative to log-based crash recovery method is shadow paging. This technique requires fewer disk accesses than do the log-based methods.

File manager-database management system, File Manager File manager ha...

File Manager File manager handles the allocation of space on disk storage. It starts and maintains the list of structures and indices described in the internal schema that is

To delete a particular column in a relation which command, To delete a part...

To delete a particular column in a relation which command is used ? To delete a particular column in a relation ALTER command is used.

Improve efficiency of database, Smart Alex Catering Sevice (SACS) is a comp...

Smart Alex Catering Sevice (SACS) is a company offering top class catering staff  for prestigious events.  The company employs approximately 200 hourly paid contact staff - chefs,

Update operations, The Update Operations : Update operations are used fo...

The Update Operations : Update operations are used for altering database values. The constraint violations faced by this operation are logically the similar as the problem faced

Convert erd to rdm model, Regional Gardens has many nurseries, including Wa...

Regional Gardens has many nurseries, including Wagga Wagga, Bathurst, Albury, Orange, and Dubbo. Each nursery is known by its campus code, eg WW, B, A, O and D respectively. Additi

Project, the of super market system done in database

the of super market system done in database

Explain concept of inheritance with support of example, Explain concept of ...

Explain concept of inheritance with support of suitable example. Inheritance Inheritance is one of milestone of object-oriented programming language as it allows a creati

What are the various properties of relational tables, What are the various ...

What are the various properties of Relational tables? Relational tables have 6 properties: 1. Each row is unique. 2. Column values are of the same kind. 3. Values are

Explain consistency model , Explain in detail the consistency model of the ...

Explain in detail the consistency model of the distributed file system you studied (GFS or AFS). Present the consistency model chosen and how it was achieved through design. Clarit

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