Stored and Derived Attributes

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In this class, we will understand Stored and Derived Attributes.

We have already discussed the concept of Simple and composite, Single-valued, and Multi-valued attributes.

Stored and Derived Attributes

For example, consider employee entity type with the attributes name, date of birth, and age, as shown below.

Stored and Derived Attributes
Stored and Derived

Stored attributes

The attribute values stored in the database are stored attributes.

In the above example, the stored attributes are name and date of birth.

Derived Attributes

The attribute values derived from the stored attributes are derived attributes.

In the above example, age cannot be a stored attribute.

The value of age has to be updated every year.

So, we can derive the value of age from the date of birth.

ER-Diagram Representation

The derived attributes are represented by the dashed oval symbol.