Evaluation Of A Good Relational Database Essay

1521 Words Apr 23rd, 2015 null Page
In order to have a good relational database and to avoid unnecessary data in your database systems you are required to perform normalisation. According to Rob et al., (2008) Normalization is a process for evaluating and correcting table structures to minimize data redundancies, thereby reducing the likelihood of data anomalies. √
Normalisation helps us to structure our database tables effectively in order to improve the performance of the database systems. Once you have a good structured table, it makes easier and more efficient when you retrieve data from the database. √
The main role of normalisation could be also described as removing duplication from the database system. For example if a name of a person appeared in more than one table (unnormalised) and you are aiming to amend the name of this particular person you will need to access each table where this name exist. In this case amending a data could be a long process. Also if you have to retrieve the data for the person above you need to go to all the tables where this person exists and this will lead to poor performance of the database system. √
Another example, Let say you have a table called Borough where you have the data about each Borough in London. In year time the government decided to combine Lambeth borough with Southwork borough. Therefore, you were asked to take out Lambeth from the table borough.
In this case how are you going to change the value in Borough table (one big table) referring to…

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