1nf 2nf 3nf and bcnf in database normalization pdf
File Name: 1nf 2nf 3nf and bcnf in database normalization .zip
The added advantage of getting an organized package of data that helps in a performance boost is also a very notable use of normalization. At the end of this article, you will be given a free pdf copy of all these Normalization forms.
Primary Key - A primary key is a column or columns in a table that uniquely identifies the rows in that table. The value placed in primary key columns must be unique for each row : no duplicates can be tolerated. In addition, nulls are not allowed in primary key columns. Foreign Key - Foreign keys are columns that point to primary key columns. E Table "office" not in first normal form, because in this table many data field contain multiple values, so it is require to convert into first normal form.
Database Normalization is a technique of organizing the data in the database. Normalization is a systematic approach of decomposing tables to eliminate data redundancy repetition and undesirable characteristics like Insertion, Update and Deletion Anomalies. It is a multi-step process that puts data into tabular form, removing duplicated data from the relation tables. The video below will give you a good overview of Database Normalization. If you want you can skip the video, as the concept is covered in detail, below the video. If a table is not properly normalized and have data redundancy then it will not only eat up extra memory space but will also make it difficult to handle and update the database, without facing data loss. Insertion, Updation and Deletion Anomalies are very frequent if database is not normalized.
What is Normalization in SQL and what are its types?
Recall that a primary key can be made up of multiple columns. As Chris said in his response:. Say you have a table containing courses that are taken in a certain semester, and you have the following data:. This is not in 2NF , because the fourth column does not rely upon the entire key - but only a part of it. The course name is dependent on the Course's ID, but has nothing to do with which semester it's taken in. Thus, as you can see, we have duplicate information - several rows telling us that IT is programming, and IT is Databases.
Prerequisite — Database normalization and functional dependency concept. Normalization is the process of minimizing redundancy from a relation or set of relations. Redundancy in relation may cause insertion, deletion and updation anomalies. So, it helps to minimize the redundancy in relations. Normal forms are used to eliminate or reduce redundancy in database tables.