Data Model

Components of ER

For example, Suppose we design a school database. In this database, the student will be an entity with attributes like address, name, id, age, etc. The address can be another entity with attributes like city, street name, pin code, etc and there will be a relationship between them.

  1. Entity(개체): Entity selection investigates, interviews with the person in charge, words used for actual work, check data flowchart. All entity must be unique.

  2. Attribute(속성): Attribute consist of a primary key, foreign key, and general properties. The primary key is an identifiable function, and the foreign key is an attribute included in the relationship with other Entity.

  3. Relationship(관계): one-to-one, one-to-many, many-to-many


3 main components of data model

  • Name
    Structures
    Type
    #1
    Description

    (구조) Primitive type (int, boolean, char, and so forth). Structured data elements are reusable, complex data types that include embedded data types. Structured data elements contain simple data elements and other structured data elements.

  • Name
    Operation
    Type
    #2
    Description

    (연산) The operations that you can perform on a data model are: add a new field to an existing data model. modify an existing field in a data model. remove a field from a data model.

  • Name
    Constraint
    Type
    #3
    Description

    (제약 조건) constraints are guidelines or limitations imposed on database tables to maintain the integrity, correctness, and consistency of the data. Constraints can be used to enforce data linkages across tables, verify that data is unique, and stop the insertion of erroneous data.