Question

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In your own word, explain why do designers use Denormalization? What is the limitation of using Denormalization? Name and explain a better alternative approach than Denormalization.

Answer :

to increase performance. In computing, denormalization is the process of trying to improve the read performance of a database, at the expense of losing some write performance, by adding redundant copies of data or by grouping data.^[1][2] It is often motivated by performance or scalability in relational database software needing to carry out very large numbers of read operations. Denormalization differs from the unnormalized form in that denormalization benefits can only be fully realized on a data model that is otherwise normalized.

Denormalization is a database optimization technique in which we add redundant data to one or more tables. This can help us avoid costly joins in a relational database. Note that denormalization does not mean not doing normalization. It is an optimization technique that is applied after doing normalization.

In a traditional normalized database, we store data in separate logical tables and attempt to minimize redundant data. We may strive to have only one copy of each piece of data in database.
For example, in a normalized database, we might have a Courses table and a Teachers table.Each entry in Courses would store the teacherID for a Course but not the teacherName. When we need to retrieve a list of all Courses with the Teacher name, we would do a join between these two tables.
In some ways, this is great; if a teacher changes is or her name, we only have to update the name in one place.
The drawback is that if tables are large, we may spend an unnecessarily long time doing joins on tables.

I have explained each and every part of the first and third question only according to "Chegg guidelines when multiple questions are given then only first question needs to be answered" with the help of statements attached to the answer above.

Answer 1

Ans:One of the main principle behind denormalization is to sort out information in order to diminish repetitive information. On the off chance that you are not needed to store a similar information again and again, you can spare a lot of room. Such association permits the expert to diminish the measure of capacity required, something that was significant when capacity was costly. We learned in the last segment that to utilize denormalized information we needed to advance through a progression of steps that included joining, arranging, and summing up. At the point when speed of questioning the information base (that is, posing an inquiry and requiring a quick reaction) is basic, it might be imperative to store information in different manners. Denormalization is the way toward taking the coherent information model and changing it into an actual model that is productive for the frequently required assignments. These assignments can incorporate report age, however they can likewise mean more effective questions. Complex inquiries, for example, online diagnostic handling (OLAP), just as information mining and information revelation (KDD) measures, can likewise utilize information bases that are denormalized.

1.Disk space: This is normal, as we'll have copy information.

2Anomalies Data: We must be mindful of the way that information currently can be changed in more than one spot. We should change each bit of copy information as needs be. That likewise applies to processed qualities and reports. We can accomplish this by utilizing triggers, exchanges or strategies for all activities that must be finished together.

3.Documentation: We should appropriately report each denormalization decide that we have applied. In the event that we adjust information base plan later, we'll need to take a gander at all our special cases and think about them indeed. Perhaps we needn't bother with them any longer since we've illuminated the issue. Or then again perhaps we have to add to existing denormalization rules. (For instance: We added another quality to the customer table and we need to store its set of experiences esteem along with all that we as of now store. We'll need to change existing denormalization decides to accomplish that).

4.Slowing other tasks: We can expect that we'll hinder information supplement, alteration, and erasure activities. On the off chance that these tasks happen moderately once in a while, this could be an advantage. Essentially, we would separate one moderate select into a bigger number of more slow supplement/update/erase questions. While an extremely intricate select inquiry actually could observably hinder the whole framework, hindering different "more modest" activities ought not harm the ease of use of our application.

5.More coding: Rules 2 and 3 will require extra coding, and yet they will streamline some select inquiries a ton. In case we're denormalizing a current information base we'll need to change these select questions to get the advantages of our work. We'll additionally need to refresh esteems in recently added credits for existing records. This also will require a additional coding.