The document provides an overview of data organization in relational database management systems (RDBMS), focusing on how tables store data in rows (records) and columns (attributes). It categorizes attributes into simple, composite, derived, single-value, multi-value, and key attributes, explaining each type with examples such as student data. Key attributes are highlighted as essential for uniquely identifying entities within an entity set.

1. Prof. Neeraj Bhargava
Pooja Dixit
Department of Computer Science
School of Engineering & System Science
MDS, University Ajmer, Rajasthan, India
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2.  In RDBMS, a table organizes data in rows and columns. The columns are
known as attributes whereas the rows are known as records.
Example: A school maintains the data of students in a table named “student”.
Suppose the data they store in table is student id, student name & student
age. To do this they have had three columns in the
table: student_id, student_age, student_name. Here student_id, student_age
and student_name are the attributes.
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4.  Simple attribute − Simple attributes are atomic values, which
cannot be divided further. For example, a student's Roll_no
number is an atomic value of 6 digits.
Example:-
 Composite attribute − Composite attributes are made of more
than one simple attribute. For example, a student's complete
name may have F_name, M_name and L_name.
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5.  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, Age in a student should
not be saved directly in the database, instead it can be derived. For
another example, age can be derived from DOB.
 Single-value attribute − Single-value attributes contain single value.
For example − Here, all the attributes are single valued attributes as
they can take only one specific value for each entity.
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6.  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.
Here, the attributes “Mob_no” and “Email_id” are multi valued
attributes as they can take more than one values for a given entity.
 Key Attributes- Key attributes are those attributes which can
identify an entity uniquely in an entity set.
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