Attributes in DBMS refer to the specific characteristics or properties of an entity that define its identity. In a relational database, attributes are the characteristic properties that collectively define an entity. An entity may contain any number of attributes, and one of the attributes is considered as the primary key. Attributes play a crucial role in defining the structure and content of a database, as well as the relationships between different entities. There are different types of attributes in DBMS, including:
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Simple/Atomic Attribute: An attribute that cannot be further subdivided into components is a simple attribute. For example, the roll number of a student or the ID number of an employee.
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Composite Attribute: An attribute that can be split into components is a composite attribute. For example, the phone number of a student can be divided into landline and mobile.
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Single-Valued Attribute: An attribute that can have only one value is a single-valued attribute. For example, the age of a student.
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Multi-Valued Attribute: An attribute that can have multiple values is a multi-valued attribute. For example, the hobbies of a student.
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Derived Attribute: An attribute that can be derived from other attributes is a derived attribute. For example, the total and average marks of a student.
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Complex Attribute: Those attributes that can be formed by the nesting of composite and multi-valued attributes are called complex attributes. These attributes are rarely used in DBMS.
Attributes are an important component of database management systems (DBMS) and are vital for designing effective databases. By properly defining and organizing attributes, including complex attributes, we can create a database that is easy to use, maintain, and expand.
