In a DBMS, an attribute is a fundamental unit representing either a table or a field within a database. It defines the characteristics of data stored within the column, enabling accurate categorization and organisation of database instances.
If not, then don't worry. In this article, we will understand how to efficiently store and retrieve data using attributes in DBMS. We will understand what are attributes in DBMS, the types of attributes, and why we need them.
What are the Attributes of DBMS?
DBMS (database management system) stores, organizes, retrieves, and manages data. It acts as an interface between the database and the user. For performing these
operations, attributes are used. There are several attributes, and each attribute has its feature. They help in describing an entity. An entity in DBMS is a data piece that is tracked and stored in the system. It consists of various attributes. So individual data make up an entity, and attributes are used to manipulate those.
Both simple and complex entities can be described using attributes. For example, a productcan be described by its ‘quality’ or multiple attributes such as ‘price,’’ quality,’’ features’ etc. Also, each attribute has a specific data type, like the price is of integer data type.
Simple attributes cannot be divided into sub-attributes. They are the primary Attributes in DBMS representing a single piece of data regarding a particular entity. They have specific data types like integers, strings, dates, etc.
For example, we have created a database of students. The simple attributes associated with this database could be names (string), roll no (integer), and marks (float).
Composite Attributes
Composite attributes DBMS consists of two or more simple attributes. They are also known as structured attributes consisting of various sub-attributes. Compared to simple attributes, the information pieces are further divided into sub-parts. They also have a hierarchical structure associated with them in a nested way. This hierarchy is used to represent the relationship between different attributes.
For example, a college student’s address consists of county(string), state (string), and pincode (integer).
Single-valued attributes only consist of one value. They are used for uniquely identifying an entity. They cannot store more than one value, and their values remain constant.
For example, a person’s name, age, and gender.
Multivalued Attributes
Multivalued attributesin DBMS consist of more than one value at a time. They are used for storing information regarding relationships between entities. Multivalued attributes are represented using arrays, tables, or collections. They also represent hierarchical data.
For example, a student can have many skills, such as ‘front-end,’ ‘blockchain,’ ‘game development,’ etc.
Derived attributes are derived from other attributes in the database. They are not stored directly in the database. They are generated according to the predefined computed values.
For example, a student’s age is derived from their date of birth, and a student’s grade is derived from the computed marks stored.
Stored attributes in DBMS remain consistent for an entity and help in deriving ‘derived attributes’. They are also known as stored columns or stored fields representing the real information about each record. In stored attributes, the values are retained even if the database is closed.
For example, an employee’s name is derived from the ‘firstName’ and ‘lastName’, where the first and the last name remain fixed and have constant values. Also, the age attribute is derived from the ‘date of birth’ attribute, which has a fixed and constant value. Therefore, the stored attributes are the ‘date of birth’, ‘firstName’, and ‘lastName’.
Complex Attributes
Complex attributes in DBMS consist of multivalued and composite attributes.
For example, an employee’s address has sub-attributes like city, state, and country. The city attribute can be further divided into house number and street number. Therefore here, the city is a complex attribute.
Key Attributes
Using key attributes, one can identify each row in a table. They help maintain data integrity and make data retrieval in a database easy. Each value in the key attribute has to be unique. For example, a primary key is a key attribute that identifies each value in a table. A table can consist of only one primary key.
For example, in a table of students, the student ID can be used as the primary key.
Attributes in DBMS are crucial for describing an entity in a database. Attributes can also be referred to as specific characteristics used to describe the data stored in the database. Here are some of the uses of attributes in DBMS.
Attributes are used to distinguish one entity from another. For example, if two students have the same name, their roll no can be used to identify them.
Attributes help organize the data in a database, and similar data can be grouped. This helps in making a searchable database. For example, if we want the names of all students with marks above 70, we can use attributes to search for those students.
Attributes help in manipulating the data by retrieving it from the database. Using attributes, we can identify specific data using specific queries and operations such as filtering, sorting, and manipulating.
Attributes can be used in DBMS to achieve Normalization. It is the process of organizing data to reduce redundancy in the database. It is done by dividing large tables into smaller ones and linking them through relationships.
Frequently Asked Questions
What is the purpose of attributes in DBMS?
The main purpose of attributes in DBMS is to define the data structure, capture entity data, ensure data integrity, and facilitate data relationships. They support data queries, indexing, and analysis while retaining data consistency and improving data security.
What are the three basic types of attributes?
The three basic types of attributes are single-valued, multi-valued, and composite attributes. The single-valued attribute can only hold a single value for each entity, whereas a multi-valued attribute holds multiple values for a single entity. Composite attributes are composed of multiple sub-attributes.
What are tuples and attributes in DBMS?
Attributes in DBMS are crucial for describing an entity in a database. Attributes can also be referred to as specific characteristics used to describe the data stored in the database. A tuple is a single row or record in a relational database table.
Conclusion
In this article, we have discussed attributes in DBMS, the types of attributes with examples, and why we need them. You can read more such articles on our platform, Coding Ninjas Studio.
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