What Is Functional Dependency?

Functional Dependency is a fancy name for the relationship between two sets of attributes. It's essential to relational database design and contributes to aspect normalization. In simple terms, functional dependency is a constraint between two sets of attributes. It helps you define the relationship between those attributes to design your databases more effectively. When an attribute depends on another attribute, it means that another determines the value of one attribute. Suppose you have an ID number in your database that must be greater than 0 and less than 100. In that case, this is an example of functional dependency—the value of the ID number depends on its relationship with other values in its row. Functional dependency is the key to normalization, which allows us to keep our data in a form that's easy to use and understand. It ensures that the attributes in your tables depend on each other rather than repeating information. That way, we know exactly what to expect when we look at a given attribute. For example, if I know that a table has an attribute called "color" and another called "size", I can guess that a third attribute will have something to do with whether or not it's for men or women. A functional dependency is an expression of how one attribute depends on another—in other words, it tells you how to get from one value to another if you already know one or more values from another column. It's pretty much like an equation: if you know X and Y, you can solve for Z (where Z is any other value). Functional dependencies are common in relational databases because they make it easier to understand how different pieces fit together. In other words: they help identify anomalies or problems in your data so that you can fix them before they become significant issues later on down the road!