Table: A table is a group of related information held in an organized format within a database . The table consists of rows and columns. Primary key: In relational databases, a primary key is a key that is used for identifying and defining the characteristics uniquely of each row. A primary key may have a single attribute or a multiple attributes. Example: Let us consider the “Student” table that consists of “Student_ID”, “First_Name”, “Last_Name”, and “Course_ID” as attributes. Student_ID act as the primary key. Foreign key: A primary key attribute in one table is the foreign key for another table. In a logical way, a foreign key is used to establish a relationship between two tables. A foreign key is used for identifying a row of another table uniquely. Foreign keys are represented in italic form. Example: The following example describes about the foreign key. Consider the “Student” table which consists of “Student_ID”, “First_Name”, “Last_Name”, and “Course_ID” are attributes and the “Course” table contains the attributes such as “Course_ID” and “Course_Name”. In this, “Student_ID” act as the primary key and the “Course_ID” act as a foreign key, because it is used to refer the “Course” table.

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Chapter 5, Problem 12DQ

Program Plan Intro

Table:

A table is a group of related information held in an organized format within a database. The table consists of rows and columns.

Primary key:

In relational databases, a primary key is a key that is used for identifying and defining the characteristics uniquely of each row.

A primary key may have a single attribute or a multiple attributes.

Example:

Let us consider the “Student” table that consists of “Student_ID”, “First_Name”, “Last_Name”, and “Course_ID” as attributes.

Student_ID act as the primary key.

Foreign key:

A primary key attribute in one table is the foreign key for another table. In a logical way, a foreign key is used to establish a relationship between two tables.

A foreign key is used for identifying a row of another table uniquely.

Foreign keys are represented in italic form.

Example:

The following example describes about the foreign key.

Consider the “Student” table which consists of “Student_ID”, “First_Name”, “Last_Name”, and “Course_ID” are attributes and the “Course” table contains the attributes such as “Course_ID” and “Course_Name”.

In this, “Student_ID” act as the primary key and the “Course_ID” act as a foreign key, because it is used to refer the “Course” table.

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