Chapter 6, Problem 1RQ

Explanation of Solution

Database:

Database is the organized collection of associated data elements which is used to have the record of things or items of interest.

• It is often defined as the structure to hold the data...

Explanation of Solution

Entity:

The basic block for building the data collected about person, place, event, or thing is called as entity.

• Entities denote attributes that can have many instances.
• Entity is about the gathering of the information about the place, person, or thing. For example: a patient, a musician, and so on.
• To locate the information in the entity, they have a name, short description about what they are and identifier.
• Identifiers are used to find each and every specific instance of an entity.
• So, it is the purpose of having identifiers with unique values.

Example:

The example of an entity is given below:

• STUDENT – the student is the person name that collects the details of student information. So the STUDENT acts as the entity.
• EMPLOYEE - the employee is the person name that collects the details of employee information. So the EMPLOYEE acts as the entity...

Explanation of Solution

Relational database:

• Relational database is a set of multiple data organized by tables, records, and columns and it creates the relationship between the database tables.
• The individual value in table provides the link from one table to another.

Storage of data in relational database:

• Relational database is a database which organizes data according to the relational model as table and table consists of rows and columns.
  • A data in a row or a column of a table is called fields.
  • Fields in a database table are also referred as attributes of a database object...

Explanation of Solution

Role of Entity-relationship diagram in database:

An entity-relationship diagram represents the important elements of database in a graphical form.

• Entity-relationship (ER) diagram is the technique used to design the relational database.
• ER diagram is useful to create the data model, which serves business process. Additionally, the diagram ensures whether data is accurate, well-formed and easy for retrieval.
• An Entity-relationship diagram is represented in the graphical form that shows only important elements such as:
  • Record types
  • Attributes
  • Relationship between entities
• For example, consider the following diagram:
  • The rectangular box represents the entities such as Customer and Account.
  • The oval symbol represents the attributes such as Firstname, Customer _id, Address, Username and Password.
  • The diamond symbol represents the relationship between two entities.
    • Here, it shows the one-to-one relationship between the Customer and Account.
      • The relationship shows that one customer is allowed to access the one account.

Role of normalization in database:

Normalization is a process of dividing the tables by more than one idea into set of tables such that each and every table contains only one idea...