Complete Guide: Denormalization in Database (DBMS)
Complete Guide: Denormalization in Database (DBMS), Techniques, Advantages, Disadvantages and why it is used: Do you know how many different ways are there to design a database? What will do if you want to optimize the database, so its performance gets a boost? If not, then this article is specially made for you. Here, we will talk about the denormalization in databases. You will get complete information about this technique for restoring the database and improve the performance.
Complete Guide: Denormalization in Database (DBMS), Techniques, Advantages, Disadvantages
What exactly denormalization is?
Denormalization can define as the technique used for normalizing the existing database for giving a boost to the performance. The approach is to make an addition of redundant data where it needed the most. There are many extra attributes used in a present table along with adding new tables. Furthermore, the instances of existing tables also created in this technique. The main motive for this strategy is to minimize the running time of chosen queries so that the queries start getting better access to the data.
What are the major database denormalization techniques?
There are plenty of techniques through which the database can be denormalized. We have explained about each of them in brief below:
- Storing derivable information
This technique is perfect to follow if you want to execute calculation repeatedly while queries. The derived calculation needs to be stored in the master table if there are detail records in it. They are perfect to use if you require derivable values more frequently or you don’t prefer to alter source values regularly.
- Moving data fields into a supertype
In this type of technique, the data fields of all the subtypes are moved into supertypes. The new model looks completely different from the normalized model. The subtypes are completely removed from the data fields using this technique.
- Using hardcore values
This technique is perfect to use if there are reference table along with consistent records. There will be no need to join the tables for getting the reference values. You need to check out the constraint for validating values with this technique. You have to rewrite a new value each time in the table.
- Copying data field from an entity
In this technique, there is no removal of the entity performed by the user. Instead, the data fields copied from one entity to another. This technique consumes very less time and boosts the retrieval speed.
Why should denormalization need to be used in the database?
It is important that you should have proper knowledge about why this technique needed to be used and when. Let’s talk about the situations where the denormalization technique should be adopted.
- Maintaining History
There is no doubt that the data changes over the time making the requirement to store valid values during the creation of the record. Some of you might be thinking what these changes can be. For instance, the first & last name of an individual can change, or modification even occurs in the business address of a client. The past data can’t be recreated correctly if the latest details don’t get added.
This problem can eliminate by making an addition of a table having the history of these modifications. In that case, denormalization can turn out to be very handy and make the process less complicated.
- Making query performance better
Many queries use the multiple tables for accessing the data that used on a regular basis. For example, you have to join five tables for returning the name of clients and items delivered to them. Lots of tables along the path may have a large quantity of data. In that scenario, the customer_id attribute should be added directly to the items_sold table.
- Facilitating reporting
Plenty of applications demand analytical and statistical details. However, there is lots of time consumed in creating reports using live data that affect the overall performance negatively. At that time, it will be wise to use the denormalization process for saving analytical details instead of calculating this data many times.
What are the major advantages of denormalization?
There are plenty of advantages offered by the denormalization in the database. You might have already understood it by checking the things mentioned above. Let’s allow to tell you about them in detail below:
- Retrieving data
The users have to join very fewer tables that boost up the process and make it less time-consuming. It can be very handy while storing the data.
- Tables reduction
There are many instances where the number of tables gets reduced by using denormalization.
What are the drawbacks of denormalization in the database?
There is a great chance that you may be thinking on why one should go for denormalizing or not. After reading this article till now, you should have assumed that it is the ideal method for boosting the performance of the database. However, there is some drawbacks associated with this technique about which you need to stay aware. We have written about each of them in detail below:
- Possible data anomalies
The amount of data needed to get modified increased during the process of denormalization. That’s why you have to check out about all the cases of duplicate data carefully. There is a requirement to utilize stored procedures, triggers, and transactions for avoiding data anomalies.
- Affecting other operation’s speed
The denormalization affects the speed of many other operations like data insertion, deletion, and modification. It is not common, but a complex query can slow down the complete system. It may be a reason to worry for some programmers and organizations.
- Additional storage space
A large amount of data needs to be duplicated during the denormalization process in the database. It results in demanding more storage space than normal.
- Extra coding
The selected queries modified in this process that no doubt brings plenty of advantages. However, you have to pay its price in the form of extra coding. Additionally, you have to make an update in the values of new attributes that added to the present records. You need a little bit of extra coding for that purpose.
- Extra documentation
It is very important to document all the steps in the denormalization process. Furthermore, the rules have to be revised if any modification in the database design happened later. It will result in increasing the documentation process.
Things to keep in mind during the denormalization process
Denormalization is a very complicated process that demands pretty serious effort and expertise. That’s why it is important that you should follow the below mentioned tips for performing this task adequately.
- Always target those components in the database that you want to boost. You should avoid trying denormalizing the complete database.
- You should have adequate learning about the logical design of the application to have a complete idea about the components affected greatly by the denormalization.
- Knowing the data storage techniques will be a plus point. It will help in picking you the most relevant one.
- The modification of data in the application needs to be analyzed carefully. The reason behind it is that the maintenance of the database’s integrity becomes difficult if data changes too frequently.
We suggest you don’t rely on the denormalization process too much and only going for it when the database requires performing better at some tasks. Creating a clean and highly defined normalized database can be greatly beneficial for a longer run. There is a need to stay pretty careful during the denormalization process as it is important to document all the modifications in the database.