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Entity – An entity can be a real-world object, either animate or inanimate, that can be easily identifiable. For example, in a school database, students, teachers, classes, and courses offered can be considered as entities. All these entities have some attributes or properties that give them their identity. Attribute – In general, an attribute is a characteristic. In a database management system (DBMS), an attribute refers to a database component, such as a table. It also may refer to a database field. Attributes describe the instances in the row of a database. Attribute Value – Attribute value is the real data of a particular entity for each of its attributes. In other word, associated with each real world entities are certain attributes that describe that entity; value of these attributes for any entity is called attribute value. For example, attribute value of first_name of attribute of student_name can be Gyanendra.  Relationship Instance – Each relationship instance ri in

i) Entities and Attributes – Entity -  An entity can be a real-world object, either animate or inanimate, that can be easily identifiable. For example, in a school database, students, teachers, classes, and courses offered can be considered as entities. All these entities have some attributes or properties that give them their identity. ii) an attribute is a characteristic. In a database management system (DBMS), an attribute refers to a database component, such as a table. It also may refer to a database field. Attributes describe the instances in the row of a database. ii) Composite and Atomic attributes –   Composite attribute − Composite attributes are made of more than one simple attribute. For example, a student's complete name may have first_name and last_name. Simple attribute (Atomic) − Simple attributes are atomic values, which cannot be divided further. For example, a student's phone number is an atomic value of 10 digits. iii) Single valued and Mul

E-R Model and Relational Model both are the types of Data Model. Data Model describes a way to design database at physical, logical and view level. The main difference between E-R Model and Relational Model is that E-R Model is entityspecific, and Relational Model is table specific. Let us discuss some differences between E-R Model and Relation model with the help of comparison chart shown below.