First Normal form in DBMS
Let’s study Database First(1st) Normal form and repeating groups.
What is the first normal form?
A relation/table is in the first normal form if it does not contains repeating groups.
What is a repeating group?
A repeating group is a group of two or more rows/records for an instance of an entity.
Example of first normal form
| Roll No | Name | Marks |
| 1 | Shahzeb | 98 |
| 2 | Basit | 90 |
| 3 | Sameed | 44 |
| 2 | Basit | 70 |
Here, Roll No 2 is the repeating group because Roll number 2 is for only one instance of an entity student.
How to convert a table into the first normal form?
We will remove the repeating groups;
| Roll No | Name | Marks |
| 1 | Shahzeb | 98 |
| 2 | Basit | 90 |
| 3 | Sameed | 44 |
Excercise 1NF to 5NF
Example: 1NF
| Original Table | ||
| Emp_ID | Name | Language |
| 1. | T4Tutorials A | English |
| 2. | T4Tutorials B | English, Chinese |
| 3. | T4Tutorials C | Chinese |
| 4. | T4Tutorials D | English, German, Russian |
FIRST NORMAL FORM
| FIRST NORMAL FORM | ||
| Emp ID | Name | Language |
| 1. | T4Tutorials A | English |
| 2. | T4Tutorials B | English |
| 2. | T4Tutorials B | Chinese |
| 3. | T4Tutorials C | Chinese |
| 4. | T4Tutorials D | English |
| 4. | T4Tutorials D | German |
| 4. | T4Tutorials D | Russian |
Topic Covered
Database First(1st) Normal form and repeating groups.
normal forms in DBMS with examples.
normalization in the database with example tables.
normalization example.
first normal form SQL.
normalization in the DBMS ppt.