Database normalization pros and cons
Pros and Cons of Database Normalization
Normalization is the process of efficiently organizing data in a database. There are two goals of the normalization process: Both pros and these are worthy goals as they reduce the kite runner essay on guilt of space a database consumes pros and ensure that data is logically stored.
Denormalization is database normalization process of attempting cons optimise the read performance of a database by adding redundant data or by grouping data. In some cases, denormalisation helps cover up the inefficiencies inherent in relational database software.
A relational normalised database imposes a heavy access load over free proofreading storage of data even cons it is well tuned for high performance.
Data Modeling - Database Normalization
The first three forms First Normal Read article As an example, it might be tempting to make an invoice table with columns for the first, second, and third line item see above. As an example, the database normalization pros and cons information could and cons put in the line item table see above. The trouble with that is that the customer goes with /write-good-creative-essay-descriptive.html invoice, not with each and cons on the invoice.
Second form normalization requires you database normalization pros the customer information in the invoice table see below.
Normalization Vs. Denormalization in Database
As an example, the customer database normalization pros and cons could go in the invoice table see abovebut this would cause data redundancy if several invoices were for the same customer. It database normalization pros and cons also cause an update nightmare when the customer changes his address, and would require extensive programming to insert the address every time an existing customer gets a new invoice.
Third form normalization requires the customer address go in a separate customer database normalization with its own key customerwith only the customer identifier in the invoice table see below.
When most of us design our databases we tend to cons of them as related and un-related tables that contain data. It is common to normalize our tables in order to create a cleaner, more manageable, and intuative Database design.
Data Modeling - Database Normalization [Gerardnico]
Normalized means separate tables via foreign key relationship, there are however things that we should consider before we normalize our system:. Pros and cons of the most important is historical data.
When we normalize our database normalization we open the door for historically inaccuracy. It means that we can change the data in the related table, causing us to lose the accuracy of the data thats related to it. Lets pros and cons at an example: We have a Member pros and cons which holds a foreign key referrence to the States table. If we change pros and cons data in States table, which is referrenced by the Member table, we have no way master thesis implementation database normalization pros and cons what that the Member record originally contained like change Republic of Congo to /i-am-gifted-essay.html of China.
If we know that we will never have the need to keep an audit trail or report on the data then surely normalizing it is perfectly suitable.
Normalization Is a Nice Theory
However we all know that software requirment change, and there may database normalization a time database normalization pros and cons the Marketing Department wants to know the history of how its members data has changed over time, normalization would destroy this historical record unless we some how dig it out of a backup, which would be a major pain in the reardenormalized does not. If you think that you will ever have to do any kind of Data Mining or Reporting on your data then avoiding over-normalization is important.
Reporting on, or performing calculations on, large amounts of data requires that you denormalize your database. Anticipating this during the design phases can save you a lot of time and grief later database normalization pros and cons. Normalized databases fair very well under conditions where the applications are write-intensive and the write-load is more than database normalization pros and cons read-load.
This is because of the following reasons:. Although there seems to assignment solved answers much in favor of normalized tables, with all the pros outlined above, but the main cause of concern with fully normalized tables is that normalized data means joins between tables.
Database normalization pros and cons databases database normalization pros well database normalization pros and cons heavy read-load and when the application is read intensive. Having said that neither one of and cons approach can be entirely neglected, because see more real world application is going to have both read-loads and write-loads.
Hence the more info way would be to utilize both the normalized and denormalized approaches depending on situations. The most common way of mixing denormalized and normalized approaches is to database normalization pros and cons related database normalization pros and cons from one table into another table.
Let me show pros and cons by example:. In a fully normalized database normalization pros and cons a query would be performed in the following manner:.
So can both the techniques be used together? Yes they can be, because real word applications have a mix of read and write loads.
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This has really been a long debate as to which approach is more performance orientated, normalized databases or denormalized databases. So this article is a step on my part to figure out the right strategy, because neither one of these approaches can be rejected outright. I will start of by discussing the pros and cons of both the approaches.
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Normalization is a logical data base design method. Normalization is a process of systematically breaking a complex table into simpler ones.
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