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Functional dependencies
Functional Dependencies A functional dependency is a relationship between two attributes in a database table. This means that one attribute can influence the...
A functional dependency is a relationship between two attributes in a database table. This means that one attribute can influence the value of another attribute, even if they are not directly related.
Let's consider the following example:
| Student Name | Student ID |
|---|---|
| John Smith | 123 |
| Jane Doe | 456 |
| David Lee | 789 |
Here, the student name attribute influences the student id attribute. This is because the student's name can be changed, even if their ID remains the same.
Functional dependencies can be established in both directions. For example:
| Product Category | Product ID |
|---|---|
| Electronics | 1 |
| Clothing | 2 |
| Furniture | 3 |
In this example, the product category attribute influences the product id attribute. This is because the product category is a characteristic of the product, and its value can determine the product id.
Functional dependencies can be used to create more complex and accurate database models. They can also help to improve the performance of database queries