Podcast
Questions and Answers
What is the main purpose of normalization?
What is the highest normal form that is of practical use?
What is the highest normal form that is mainly of academic interest?
What must a table have in order to satisfy 1NF?
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What is a columnar data store?
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Study Notes
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Normalization is a database design technique that is used to improve the data integrity of a relational database.
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Normalization is a progressive process that must be followed in order to achieve a higher level of normalization.
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Normalization aims to reduce data redundancy and improve data integrity.
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The first step in normalization is to ensure compliance to first normal form.
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The second step in normalization is to ensure second normal form is satisfied.
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Normal forms beyond 4NF are mainly of academic interest, as the problems they exist to solve rarely appear in practice.
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The data in the following example were intentionally designed to contradict most of the normal forms.
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A table must have a primary key to conform to the relational model.
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A table must have a single column primary key to satisfy 1NF.
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A table must have a multi-column or composite key to satisfy 2NF.
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A table may not satisfy 4NF if it has a compound primary key.
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To satisfy 4NF, a table must have a single column primary key and be in BCNF.
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A table is in 6NF when the row contains the Primary Key, and at most one other attribute.
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A table in 5NF has one primary key column and N attributes, representing the same information in 6NF will require N tables.
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In data warehouses, which do not permit interactive updates and which are specialized for fast query on large data volumes, certain DBMSs use an internal 6NF representation - known as a columnar data store.
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A database table is a collection of data that is stored in a database.
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A database table can have multiple columns, which are the individual data elements that make up the table.
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A database table can also have a "primary key" column, which is a column that uniquely identifies each row in the table.
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A database table can also have a "unique index" column, which is a column that helps to ensure that each row in the table is unique.
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A database table can be "normalized" by creating separate tables for each of the columns in the table.
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Some DBMSs, such as Sybase IQ, use columnar storage by default, which means that the table is stored in a single multi-column table.
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Other DBMSs, such as Microsoft SQL Server 2012 and later, let you specify a "columnstore index" for a particular table, which means that the table is stored in a column-based storage format.
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Normalization can help to ensure that the data in a table is organized in a consistent way and that the data is easily searchable.
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Description
Test your knowledge of database normalization with this quiz. Learn about the progressive process of normalization, the various normal forms, primary keys, and the impact of normalization on data organization and integrity.