termed entities, and relationships among these objects. The concept originated from Peter Chen's 1976 paper, "The Entity-Relationship Model - Toward a Unified View of Data". Since then, it has been utilized as a tool to aid in the design of relational databases,...
Now B.tech have these things like Stream(civil,mechanical,Cs etc), Subjects, projects etc.these are called Attributes. A basic knowledge of entity,entity set and attributes is necessary in making E-R Diagram which is further significant when you are working on some project and you...
ER Diagrams contain different symbols that use rectangles to represent entities, ovals to define attributes and diamond shapes to represent relationships. At first look, an ER diagram looks very similar to the flowchart. However, ER Diagram includes many specialized symbols, and its meanings make thi...
The entity type is a collection of the entity having similar attributes. In the above Student table example, we have each row as an entity and they are having common attributes i.e each row has its own value for attributes Roll_no, Age, Student_name and Mobile_no. So, we can define ...
1a :being, existence especially: independent, separate, or self-contained existence. b : the existence of a thing as contrasted with its attributes. 2 : something that has separate and distinct existence and objective or conceptual reality. ...
An ER diagram shows the relationship among entity sets. An entity set is a group of similar entities and these entities can have attributes. In terms of DBMS, an entity is a table or attribute of a table in database, so by showing relationship among tables and their attributes, ER diagram...
The composite entity has its own attributes and primary key, and it serves as a connector between the two entities it relates. In the case of the student and course entities, a composite entity called "enrollment" could be created, which would have attributes such as "semester," "grade," ...
In a typical ER design, you can find symbols such as rounded rectangles and connectors (with different styles of their ends) that depict the entities, their attributes, and inter-relationships. When to draw ER Diagrams? So, when do we draw ERDs? While ER models are mostly developed for des...
Entity-Relationship (ER) diagrams are graphical representations used in database design to illustrate the structure of a database system. They depict the entities (objects or concepts) within a system, the attributes that describe them, and the relationships between these entities. ...
Difference between Strong and Weak Entity: Entity Keys:It is an attribute that helps to define an entity uniquely within an entity set. Entity keys can be categorized as: Super key:A set of attributes that helps together define an entity uniquely, within an entity set. ...