posted Dec 2020

Author: jsdnhk

_data/links.yaml

@@ -58,6 +58,7 @@
     - https://extendsclass.com
     - https://regexr.com
     - https://regex101.com
+    - https://codesandbox.io
     - https://css2sass.herokuapp.com
     - https://app.programmingfonts.org
 

_data/pages_latest.yaml

@@ -1,12 +1,12 @@
 ---
 - name: blog
-  mtime: 1-11-2020
+  mtime: 1-12-2020
 - name: debug
   mtime: 12-10-2020
 - name: fonts
   mtime: 12-10-2020
 - name: links
-  mtime: 12-10-2020
+  mtime: 1-12-2020
 - name: quotes
   mtime: 12-10-2020
 - name: resume

assets/posts/2020-12-01/db-normalization-graph.jpg

@@ -0,0 +1,42 @@
+---
+title: "Make DB tables great by normalization"
+tags: [development, database]
+category: "database"
+comment: true
+
+---
+
+## Introduction
+
+Nowadays, almost all scalable softwares are connected to database for data persistence need.
+
+Relational database is the most common and widely-used one, without that no any data can be stored and reused.
+
+The relationship and organization inside the database are always an important section to make data collected well.
+
+Thus, DB normalization was then proposed and become the guildline of making relational DB tables.
+
+It mainly eliminates irrelevant fields and duplication of data, to give normal data manipulation and data integrity.
+
+
+## Rules
+
+There are the progressive rules for database normalization, if obey then they call "1st/2nd/3rd normal form".
+
+![db-normalization-graph](/assets/posts/2020-12-01/db-normalization-graph.jpg)
+
+### Level 1: 1st normal form
+- Eliminate repeating groups in individual tables
+- Create a separate table for each set of related data
+- Identify each set of related data with a primary key
+
+### Level 2: 2nd normal form
+- Create separate tables for sets of values that apply to multiple records
+- Relate these tables with a foreign key
+
+### Level 3: 3rd normal form
+- Eliminate fields that do not relate to the key item to become atomic
+
+*For more detailed instruction, this [poster][db-normalization-poster] provides the full solution.*
+
+[db-normalization-poster]: http://marcrettig.me/wp-content/uploads/2017/04/rettigNormalizationPoster.pdf