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DBMS First Normal Form (1NF)
Definition:
First Normal Form (1NF) is the basic level of database normalization. It requires that all table columns contain atomic, indivisible values and each column contains values of a single type.
Atomicity:
Ensures that each column value is atomic, meaning it cannot be further divided. For example, in a table storing addresses, each component (street, city, state) should be in separate columns.
Uniqueness:
Each row must be unique. This is typically achieved by having a primary key that uniquely identifies each row in a table.
Single Valued Columns:
Columns should not contain repeating groups or arrays. Each column should store a single value for each record.
Example Table Before 1NF:
Consider a table with columns for student names and courses. If a student is enrolled in multiple courses, these should not be stored in a single column.
StudentID | Name | Courses
--------------------------------
1 | John Doe | Math, Science
2 | Jane Roe | English, History
Transforming to 1NF:
To convert the table to 1NF, separate the courses into individual rows.
StudentID | Name | Course
------------------------------
1 | John Doe | Math
1 | John Doe | Science
2 | Jane Roe | English
2 | Jane Roe | History
Benefits of 1NF:
Ensures a clear structure and eliminates redundancy, making the database easier to maintain and query.
