Database Fundamentals Quiz

Grade 9 · Technology · Quiz

Assess your understanding of relational databases, SQL queries, data modeling, and database design principles.

Questions

1. In a relational database, what does a row in a table represent?

   1. An attribute or characteristic
   2. A data type definition
   3. A single record or instance of the entity
   4. A relationship between two tables
   Show answer

   Answer: A single record or instance of the entity

   A row (also called a record or tuple) represents a single instance of the entity the table describes — for example, one specific student.

2. Which SQL clause is used to filter rows based on a condition?

   1. ORDER BY
   2. GROUP BY
   3. WHERE
   4. HAVING
   Show answer

   Answer: WHERE

   The WHERE clause filters rows based on a specified condition, returning only records that satisfy it.

3. A Students table has a column called `course_id` that refers to the primary key of a Courses table. The `course_id` column in Students is a:

   1. Secondary key
   2. Foreign key
   3. Composite key
   4. Candidate key
   Show answer

   Answer: Foreign key

   A foreign key is a column that references the primary key of another table, establishing a relational link between the two tables.

4. Which SQL command would you use to add a new record to a table?

   1. ADD INTO
   2. CREATE RECORD
   3. INSERT INTO
   4. APPEND VALUES
   Show answer

   Answer: INSERT INTO

   INSERT INTO is the correct SQL syntax for adding new records to a table: INSERT INTO table (columns) VALUES (values);

5. What does the following SQL query do? SELECT name FROM students WHERE grade > 85;

   1. Deletes all students with a grade above 85
   2. Updates the grade column for all students named 'name'
   3. Returns the names of all students whose grade is greater than 85
   4. Creates a new table with students who scored above 85
   Show answer

   Answer: Returns the names of all students whose grade is greater than 85

   The query SELECTs the name column FROM the students table WHERE the grade column value is greater than 85, returning a list of qualifying student names.

6. Which of the following best describes a one-to-many relationship in a relational database?

   1. One record in Table A matches exactly one record in Table B
   2. One record in Table A can be associated with many records in Table B
   3. Many records in Table A match many records in Table B
   4. A table that has no relationships with other tables
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   Answer: One record in Table A can be associated with many records in Table B

   A one-to-many relationship means one record in the parent table (e.g., one teacher) can relate to many records in the child table (e.g., many students).

7. NULL in a database field means the value is zero.

   Show answer

   Answer: False

   NULL means the value is absent, unknown, or not applicable — it is distinctly different from zero (0) or an empty string.

8. The SQL command used to remove records from a table is ______.

   Show answer

   Answer: delete

   The DELETE statement removes rows from a table: DELETE FROM table WHERE condition;

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