Overview
This lecture explains the First Normal Form (1NF) in database normalization, its importance, key rules, and provides an example of applying 1NF to a student table.
Introduction to First Normal Form (1NF)
- 1NF is the initial step in the database normalization process.
- Tables not in 1NF are considered poorly designed databases.
- Moving a table to 1NF is necessary before progressing to higher normal forms.
Rules of First Normal Form
- Each column must have single-valued (atomic) entries; no multiple values in a single cell.
- All values within a column should be of the same data type or kind.
- Every column in the table must have a unique name to prevent confusion during data retrieval.
- The order of storing data in the table does not affect the table’s design or functioning.
Example: Student Table and 1NF Application
- The example table stores student roll number, name, and subjects chosen.
- Initial table may violate 1NF if multiple subjects are stored in one cell.
- To achieve 1NF, split multi-valued cells (e.g., subjects) so each row has one subject per student.
- After adjustment, each column contains atomic values, fulfilling 1NF.
Key Terms & Definitions
- Normalization — Process of organizing data to reduce redundancy and improve data integrity.
- First Normal Form (1NF) — A table format where each column contains atomic, single-valued entries, all values in a column are the same type, columns are uniquely named, and row order is irrelevant.
- Atomic Value — A value that cannot be divided further in the context of the database (single value per cell).
Action Items / Next Steps
- Practice converting non-1NF tables to 1NF by making all columns atomic.
- Review the concepts of normalization and prepare for learning about the Second Normal Form (2NF).