Explain following terms with suitable example

(i) Primary key (ii) Candidate key (iii) Foreign key (iv) Super key

i. Primary key:

• A primary key is a special relational database table column (or combination of columns) designated to uniquely identify all table records.
• A primary key’s main features are:
  • It must contain a unique value for each row of data.
  • It cannot contain null values.
• A primary key is …