Relational Database Concepts

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Questions and Answers

In a relational database, what is the primary purpose of a foreign key?

To ensure data consistency by referencing a primary key in another table. (correct)
To uniquely identify each record within its own table.
To provide an alternate key option if the primary key is not available.
To automatically generate values for a specific column.

Consider a scenario where a student database has 'Students' and 'Courses' tables. A student can enroll in multiple courses, and a course can have multiple students. What type of relationship exists between 'Students' and 'Courses'?

One-to-one
Many-to-one
Many-to-many (correct)
One-to-many

Which DDL command is used to remove all rows from a table while retaining the table structure (column definitions)?

DELETE
DROP
REMOVE
TRUNCATE (correct)

When designing a database for storing employee information, which data type would be most appropriate for storing an employee's date of birth?

DATE (D) Signup and view all the answers

What is the purpose of the `WHERE` clause in an SQL `SELECT` statement?

To filter the rows based on a specified condition. (A) Signup and view all the answers

What distinguishes a composite primary key from a simple primary key?

A composite key consists of multiple columns to uniquely identify rows, whereas a simple primary key uses only one column. (C) Signup and view all the answers

Which SQL command is used to modify existing data within a table?

UPDATE (B) Signup and view all the answers

In the context of databases, what does referential integrity ensure?

Maintains consistency between related tables by enforcing rules on foreign key values. (D) Signup and view all the answers

Which of the following is NOT a characteristic of a good primary key?

Mutable (D) Signup and view all the answers

Consider an `INSERT` statement in SQL. What is the correct syntax to insert a new row into a table named 'Customers' with columns 'CustomerID', 'Name', and 'City', using values 101, 'John Doe', and 'New York' respectively?

Both A and B are acceptable syntaxes. (C) Signup and view all the answers

Flashcards

What is a Database?

Structured storage for data, minimizing duplication and enabling easy retrieval.

What is a Relational Database (RDBMS)?

A database with multiple interconnected tables to minimize redundancy.