Add Database normalization description and ref (#1345)

* Add Database normalization description and ref

* Update content/roadmaps/101-backend/content/108-more-about-databases/104-database-normalization.md

Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

content/roadmaps/101-backend/content/108-more-about-databases/104-database-normalization.md

@@ -1 +1,10 @@
-# Database normalization
+# Database Normalization
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+Database normalization is the process of structuring a relational database in accordance with a series of so-called normal forms in order to reduce data redundancy and improve data integrity. It was first proposed by Edgar F. Codd as part of his relational model.
+
+Normalization entails organizing the columns (attributes) and tables (relations) of a database to ensure that their dependencies are properly enforced by database integrity constraints. It is accomplished by applying some formal rules either by a process of synthesis (creating a new database design) or decomposition (improving an existing database design).
+
+<ResourceGroupTitle>Free Content</ResourceGroupTitle>
+
+<BadgeLink colorScheme='blue' badgeText='Guru99' href='https://www.guru99.com/database-normalization.html'>What is Normalization in DBMS (SQL)? 1NF, 2NF, 3NF, BCNF Database with Example</BadgeLink>
+<BadgeLink colorScheme='blue' badgeText='Wikipedia' href='https://en.wikipedia.org/wiki/Database_normalization'>Database normalization</BadgeLink>