The attributes that do not exist in the physical database

Types of Attributes • Simple attribute− Simple attributes are atomic values, which cannot be divided further. For example, a student's phone number is an atomic value of 10 digits. • Composite attribute− Composite attributes are made of more than one simple attribute. For example, a student's complete name may have first_name and last_name. • Derived attribute− Derived attributes are the attributes that do not exist in the physical database, but their values are derived from other attributes present in the database. For example, average_salary in a department should not be saved directly in the database, instead it can be derived. For another example, age can be derived from data_of_birth. • Single-value attribute− Single-value attributes contain single value. For example − Social_Security_Number. • Multi-value attribute− Multi-value attributes may contain more than one values. For example, a person can have more than one phone number, email_address, etc.