Data redundancy

• How does storing multiple unrelated attributes in a single table lead to insertion anomalies?

  It forces unnecessary data entry for new records
• What is a consequence of deletion anomalies in databases?

  Unnecessary data loss occurs
• What are update anomalies?

  Issues when updating requires multiple row changes
• How do the three actions on anomalies (update, delete, insert) relate to maintaining data integrity and consistency in a DBMS?

  Performing these actions helps ensure the database remains accurate, complete, and free of contradictions
• Why do deletion anomalies occur?

  They occur when unrelated attributes are grouped
• What is the benefit of having one entity linked to multiple associated entities?

  It reduces data redundancy
• What type of relationship is created by linking entities with keys?

  A one-to-many relationship
• What does 2NF eliminate?

  Deletion anomalies
• How should related entities be linked in a database?

  Using primary and foreign keys
• What are the three main forms of normalization?

  1. First Normal Form (1NF)
  2. Second Normal Form (2NF)
  3. Third Normal Form (3NF)
• What is the key requirement for 3NF?

  No transitive dependencies through non-primary attributes
• Why is the insertion anomaly problematic?

  It forces immediate course enrollment for new students
• What are the three types of anomalies in a database?

  • Insertion Anomaly
  • Deletion Anomaly
  • Update Anomaly
• What are insertion anomalies?

  Issues when adding data without unnecessary information
• Why is it crucial to avoid anomalies in databases?

  To maintain proper database design and normalization
• What are deletion anomalies?

  Issues from deleting rows that remove necessary information
• What is the key requirement for 2NF?

  Eliminate transitive dependencies
• How can update anomalies affect data integrity?

  They can lead to inconsistent data across rows
• In a student-course table, what happens if a student changes their name?

  It must be updated in every enrolled row
• What happens when a student is deleted in a properly designed database?

  Courses remain unaffected
• What anomaly can be avoided by allowing students to be added without immediate enrollment?

  Insertion anomaly
• What can you infer about the relationship between the red and green channels from the scatter plot?

  • The scatter plot shows a positive correlation between the red and green channels, indicating that as the intensity in one channel increases, the intensity in the other channel also tends to increase.
  • However, the scatter plot also shows a lot of variability, suggesting that the relationship between the red and green channels is not perfectly linear.
• What is the purpose of deleting an anomaly in a DBMS?

  • To remove an unwanted or incorrect anomaly from the database
  • To maintain data integrity and consistency
• If you wanted to observe the detailed surface features of a cell, which type of microscope would you likely use to generate data similar to what is shown in these images?

  Scanning electron microscope (SEM)
• Why is the deletion anomaly an issue?

  It can lead to loss of important course information
• What does 1NF eliminate?

  Insertion anomalies
• What type of microscopy technique is likely used to generate this data?

  • Based on the scatter plot and the LOG intensity plot, this data is likely generated from a fluorescence microscopy technique, where the intensity of the red and green channels are measured.
• How does data redundancy affect storage costs?

  It leads to wasted space and increased costs
• What is the first step to avoid anomalies in databases?

  Design separate tables for unrelated attributes
• Why is the update anomaly considered tedious?

  It requires updating every row for the student
• What is data inconsistency in database systems?

  Complex updates leading to potential errors
• What does storage overhead refer to in database systems?

  Increased storage needed due to redundancy
• What happens during a deletion anomaly?

  All course enrollments are deleted with the student
• What is the relationship between the intensity in the red channel and the LOG intensity in the red channel?

  • The intensity in the red channel and the LOG intensity in the red channel have a linear relationship.
  • As the intensity in the red channel increases, the LOG intensity in the red channel also increases linearly.
• How do the requirements of 1NF, 2NF, and 3NF differ?

  They address different types of data anomalies
• What is the significance of eliminating anomalies in databases?

  It enhances data integrity and usability
• What is the approximate range of LOG intensity values in the red channel shown in the second image?

  8 to 16
• What changes occur in database structure from a single table to multiple tables?

  • Single Table: StudentName, Course1, Course2, Grade1, Grade2
  • Multiple Tables:
  • Student
  • Course
  • Enrollment
• What happens when a student changes their name in a database?

  Updating each enrollment row can be tedious
• What are the three main actions that can be performed on anomalies in a DBMS?

  Update anomaly, delete anomaly, insert anomaly