Free Printable 12B revew midterms

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12B revew midterms

Total questions: 17

Worksheet time: 16mins

Name

Class

Date

What does ERD stand for in database design?

Entity Relationship Data

Entity Relationship Diagram

Entity Reference Diagram

Enhanced Relational Database

In an ERD, what do rectangles represent?

Relationships

Attributes

Entities

Primary Keys

What is the purpose of a primary key in a database table?

To link tables together

To allow duplicate values in a table

To uniquely identify each record

To store large amounts of text

Which SQL command is used to create a new table in SQLite?

INSERT INTO

CREATE TABLE

NEW TABLE

ADD TABLE

What type of relationship exists when one record in Table A relates to many records in Table B?

One-to-One

One-to-Many

Many-to-Many

None of the above

What is the SQL syntax to define a foreign key in SQLite?

FOREIGN KEY (column_name) REFERENCES table_name(column_name)

SET FOREIGN KEY (column_name) IN table_name(column_name)

ADD FOREIGN KEY (column_name) TO table_name(column_name)

LINK FOREIGN KEY (column_name) WITH table_name(column_name)

Which of the following best describes a one-to-one relationship?

One student can enroll in multiple courses

A country has multiple cities

Each passport belongs to exactly one person

A book can be borrowed by multiple students

In an ERD, what symbol is typically used to represent a many-to-many relationship?

A solid line

A crow’s foot

A double circle

A triangle

What happens if you try to insert a duplicate value into a primary key column?

SQLite will allow it

SQLite will generate a warning but insert the data

SQLite will reject the insertion with an error

SQLite will replace the existing record

10.

What are the three main components of an ERD?

Classes, Methods, Objects

Tables, Columns, Rows

Nodes, Edges, Weights

Entities, Relationships, Attributes

11.

Describe the difference between a primary key and a foreign key.

A primary key can be duplicated across tables, while a foreign key cannot.

A primary key uniquely identifies a record in a table, while a foreign key links to a primary key in another table.

A primary key is always a string, while a foreign key is always an integer.

A primary key is used for indexing, while a foreign key is used for sorting records.

12.

Write an SQL statement to create a Students table with the following fields: id (primary key), name, and age.

CREATE TABLE Students (id INT PRIMARY KEY, name VARCHAR(255), age INT);

CREATE TABLE Students (id INT, name TEXT, age INTEGER);

CREATE TABLE Students (student_id INT PRIMARY KEY, full_name VARCHAR(100), years INT);

13.

Write an SQL statement to create a Courses table with course_id as the primary key and course_name as a text field.

CREATE TABLE Courses (course_id SERIAL PRIMARY KEY, course_name STRING);

CREATE TABLE Courses (course_id INT, course_name VARCHAR);

CREATE TABLE Courses (course_id INT PRIMARY KEY, course_name VARCHAR(255));

CREATE TABLE Courses (course_id INT PRIMARY KEY, course_name TEXT);

14.

Write an SQL statement to create an Enrollments table that links Students and Courses using foreign keys.

CREATE TABLE Enrollments ( enrollment_id INT PRIMARY KEY, student_id INT, course_id INT, FOREIGN KEY (student_id) REFERENCES Students(student_id), FOREIGN KEY (course_id) REFERENCES Courses(course_id) );

CREATE TABLE Enrollments (enrollment_id INT, student_id INT, course_id INT);

CREATE TABLE Enrollments (enrollment_id INT PRIMARY KEY, student_id VARCHAR(255), course_id VARCHAR(255));

CREATE TABLE Enrollments (enrollment_id INT PRIMARY KEY, student_id INT, course_id INT, PRIMARY KEY (course_id));

15.

How would you represent a one-to-many relationship in an ERD?

4 lines

16.

Why is it important to set NOT NULL constraints on certain columns in a table?

4 lines

17.

If you were designing an ERD for an e-commerce system, what three main entities would you include?

4 lines

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12B revew midterms

Total questions: 17

Worksheet time: 16mins

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