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In data modeling, an '''entity''' represents a real-world object, concept, or thing (e.g., a customer, product, employee, etc.). Attributes provide details about these entities. They describe specific aspects or features of the entity. For example: | In data modeling, an '''entity''' represents a real-world object, concept, or thing (e.g., a customer, product, employee, etc.). Attributes provide details about these entities. They describe specific aspects or features of the entity. For example: | ||
* An '''Employee''' entity may have attributes such as | * An '''Employee''' entity may have attributes such as Name, Employee ID, Salary, and Department. | ||
* A '''Product''' entity may have attributes like | * A '''Product''' entity may have attributes like Product Name, Price, and Category. | ||
===== '''Types of Attributes''' ===== | ===== '''Types of Attributes''' ===== | ||
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* '''[[Documentation:Derived settable attributes|Derived Settable Attributes]]''': As Derived Attribute above, but also has a EAL expression that can write data back to the source attributes of the derivation. | * '''[[Documentation:Derived settable attributes|Derived Settable Attributes]]''': As Derived Attribute above, but also has a EAL expression that can write data back to the source attributes of the derivation. | ||
===== '''Role in Data | ===== '''Role in Data Modeling''' ===== | ||
Attributes play a crucial role in creating a data model (such as in a [[Documentation:Class diagrams|Class diagram]]). They help define the structure of a database schema and guide the creation of database tables. | Attributes play a crucial role in creating a data model (such as in a [[Documentation:Class diagrams|Class diagram]]). They help define the structure of a database schema and guide the creation of database tables. | ||
Attributes provide essential information about entities in a data model, allowing us to represent and organize data effectively. | Attributes provide essential information about entities in a data model, allowing us to represent and organize data effectively. | ||
See also: | |||
Revision as of 05:39, 16 May 2024
An attribute refers to a property or characteristic associated with an entity, class, or object.
Entities and Attributes
In data modeling, an entity represents a real-world object, concept, or thing (e.g., a customer, product, employee, etc.). Attributes provide details about these entities. They describe specific aspects or features of the entity. For example:
- An Employee entity may have attributes such as Name, Employee ID, Salary, and Department.
- A Product entity may have attributes like Product Name, Price, and Category.
Types of Attributes
- Persisted Attributes: Represent basic data types (e.g., strings, numbers, dates) and are stored automatically in the database.
- Transient Attributes: Represent basic data types (e.g., strings, numbers, dates) and are only kept in memory. When a user session end, the information is lost.
- Derived Attributes: Calculated or derived from other attributes (e.g., age based on birthdate) using an OCL expression
- Derived Settable Attributes: As Derived Attribute above, but also has a EAL expression that can write data back to the source attributes of the derivation.
Role in Data Modeling
Attributes play a crucial role in creating a data model (such as in a Class diagram). They help define the structure of a database schema and guide the creation of database tables.
Attributes provide essential information about entities in a data model, allowing us to represent and organize data effectively.
See also:
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