Entity is an object, can be independent or dependent object. e.g A Student, Lecturer OR Employee can be a entity where as the attributes are the properties of the entity. e,g name, age, birthdate, degree.
to answer your question create 3 X 4 matrix, add entity names in column heading and attributes in a row label. and fill in the information for each entity.
Entities are one type of storage place where we can store information whereas attributes is the piece of information for that entity. Example : The book is the entity set. Title, price, author name all are the attributes of the book entity.
In a relational database, a weak entity is an entity that cannot be uniquely identified by its attributes alone; therefore, it must use a foreign key in conjunction with its attributes to create a primary key.Wikipedia
A relationship with attributes should be an associative entity when: - All relationships for the associative entity should be many - The associative entity could have meaning independent of the other entities - The associative entity should have attribute(s), but it may or may not have an identifier - The associative entity may participate in other relationships other than the entities of the associated relationship - Ternary relationships should be converted to associative entities
A database object is represented as one of the following: database, schema, table, column, primary key, and foreign key A database Entity is: An entity is a thing or object of importance about which data must be captured. All things aren't entities - only those about which information should be captured. Information about an entity is captured in the form of attributes and/or relationships. If something is a candidate for being an entity and it has no attributes or relationships, it isn't an entity. Database entities appear in a data model as a box with a title. The title is the name of the entity.
Possessive: entity's Plural: entities Possessive plural: entities'
lets understand them all: 1.An Entity is a real world "thing" which have independent existence. 2.Entity type is a category. 3.entity type is strictly calling, "an instance of entity type". 4.An entity type defines a collection of entities that have the same attributes. 5.Entity set : the collection of all entities of a particular entity type in the database at any point of time is called Entity set.
differents between entity and attributes
Entity Type : A collection of entities that share common properties or characteristics. for example student is an entity type with common attributes such as student_ID , Name, Class etc. These characteristics are common to all students. Entity Instance: A single occurrence of a particular entity type is called entity instance..
ERD is an Entity Relationship Diagram which is a graphical representation of database entities (tables, table columns, table definitions, attributes) and inter-relationships between these entities (how the tables are connected).
To draw a relationship diagram, start by placing relationship at the center of the paper. Connect entities to the relationship, and branch out with the different attributes.
If you have a many-to-many relationship between two entities you create an intermediate entity between.Now, the relationship between the first entity and intersection entity is one-to-many, and the relationship between the second entity and intersection entity is one-to-many also.