The document provides guidance on common SQL query issues and their resolutions, aimed at assisting students and professionals in database management. It addresses specific query errors, explains their causes, and offers corrected queries to enhance SQL skills. Additionally, the document emphasizes the importance of understanding SQL errors and invites users to seek expert help for database-related assignments.

1. Database Homework Help
Topic: SQL Query Fixes and Database Design Solutions
For any Assignment related queries, Call us at : - +1 (336) 559-3795
You can mail us at : - info@databasehomeworkhelp.com
Reach us at : - https://www.databasehomeworkhelp.com/

2. https://www.databasehomeworkhelp.com/
Introduction
Welcome! Today, we'll explore common SQL query
issues and their solutions. We'll address typical
errors, explain their causes, and provide corrected
queries. DatabaseHomeworkHelp.com is dedicated
to supporting students and professionals with their
database challenges. Our experts offer step-by-step
guidance to help you master SQL and achieve your
academic and professional goals.

3. https://www.databasehomeworkhelp.com/
Question I-1
Title: Error in Finding Parcels Owned by Gerald
Rappaport
• Original Query:
• Error Message: ORA-00904: invalid column name

4. https://www.databasehomeworkhelp.com/
Question I-1a
Title: Why Does the Query Fail?
• Issue: The query fails due to the use of double
quotes for string literals in SQL.
• Explanation: In SQL, single quotes should be used
for string literals, not double quotes.

5. https://www.databasehomeworkhelp.com/
Question I-1b
Title: Corrected Query
• Revised SQL Query:
• Expected Output: Displays parcels owned by
Gerald Rappaport.

6. https://www.databasehomeworkhelp.com/
Question I-2
Title: Query for Parcels with Specific Criteria
• Original Query

7. https://www.databasehomeworkhelp.com/
Question I-2a
Title: Why Doesn’t the Query Produce the Correct
Result?
• Issue: The use of OR without proper parentheses
causes incorrect results.
• Explanation: The query fetches all parcels with
either sqft > 20000 or wpb = 112, causing
duplicate entries.

8. https://www.databasehomeworkhelp.com/
Question I-2b
Title: Corrected Query
• Revised SQL Query
• Expected Output: Correct listing of parcels with
at least one fire, avoiding duplicates.

9. https://www.databasehomeworkhelp.com/
Question I-3a
Title: Normal Form Violation in Keywords Table
• Issue: The table violates the First Normal Form
(1NF).
• Explanation: 1NF requires that each column
contains only atomic (indivisible) values. If the
table stores multiple keywords in a single column,
it violates 1NF.

10. https://www.databasehomeworkhelp.com/
Question I-3b
Title: Redesign to Correct Normal Form Violations
• Redesign Steps:
• Create a New Table: keywords with columns for
keyword_id, keyword_value.
• Link with Existing Tables: Establish a relationship
with the relevant tables through foreign keys.
• Keys and Relationships:
• keyword_id as the primary key.
• Foreign key relationships with authors, titles, and
other related tables.

11. https://www.databasehomeworkhelp.com/
Question I-4
Title: Updating Building Values Based on Fire Losses
Initial Query for Testing:

12. https://www.databasehomeworkhelp.com/
Question I-4a
Title: Why Were All Rows Updated?
•
Issue: The use of a LEFT JOIN in the subquery
allows NULL values to be included, causing
updates to all rows.
• Explanation: NULL values in the bldval column
lead to all rows being affected.

13. https://www.databasehomeworkhelp.com/
Question I-4b
Title: Corrected Update Statement
Revised SQL UPDATE Statement

14. https://www.databasehomeworkhelp.com/
Conclusion
To wrap up, understanding and resolving SQL query
errors is vital for effective database management.
We’ve covered typical issues and provided solutions to
enhance your SQL skills. For specialized assistance with
database assignments and more, visit
DatabaseHomeworkHelp.com. Our expert team is here
to offer personalized support and help you excel in
your studies and career. Thank you for your attention!

15. https://www.databasehomeworkhelp.com/
Thank you …