_________ are groups of similar cells that act as a functional unit

GRAMÁTICA -B (5 items, 10 points) Read the following sentences very carefully and fill in the blanks with the correct form of the present perfect of the verbs in parentheses. You must type two words in each blank. Don’t forget to mark accent marks and special characters when appropriate.   Mi hermano y yo (ver)   varias películas en japonés. Tú y yo nunca (romperse)   ningún hueso. Yo (ir) a España dos veces. Mi jefe no me (dar) unos días libres en mucho tiempo. Yo nunca (escribir) un poema. 

Disadvantage of too many indexes?

Normal Form: No partial dependencies?

Problem Statement: Imagine a database table called Student_Records that contains 1,000,000 rows of data, but currently has NO indexes created on it. The Search Scenario: If you run a query to find a specific student ID (SELECT * FROM Student_Records WHERE ID = 900500), what method must the database use to find this record, and why is it slow? (3 Marks) The Solution: If you create a Primary Index on the ID column, how does the search method change? (You may use the analogy of finding a topic in a textbook to explain). (4 Marks) The Trade-off: If indexes make searching so much faster, why don’t we just create an index on every single column (Name, Age, Address, Phone, etc.)? Give one disadvantage of having too many indexes. (3 Marks)

ER Diagram: Shape for Relationship?

SQL: Which clause removes duplicates?

Problem Statement: In a database system, a Transaction is a sequence of operations that is treated as a single logical unit. To ensure data integrity, transactions must adhere to the ACID properties. Consider the following scenario: Scenario: Alice is transferring $500 to Bob. Step 1: The bank database deducts $500 from Alice’s account. Step 2: Suddenly, the power goes out before the database can add the $500 to Bob’s account. Step 3: When the power returns, the database automatically cancels the deduction from Alice’s account, ensuring money didn’t just “disappear.” Answer the following: Define the Acronym: Write down what each letter in C.I.D. stands for. (4 Marks) Identify the Property: Which specific property of ACID is responsible for the “All or Nothing” behavior described in the scenario above (where the half-finished transaction was cancelled)? (3 Marks) Durability Check: Once the transaction is successfully completed and “Committed,” which ACID property guarantees that the data will remain saved even if the system crashes 5 seconds later? (3 Marks)

You are designing a database for an elite cybersecurity training camp. The relation is: Session(Student, Subject, Instructor) The Rules (Functional Dependencies): Rule A: For any given Subject, a Student is assigned to exactly one Instructor. (e.g., If John studies “Ethical Hacking”, he has exactly one instructor for it). Rule B: An Instructor is a specialist who teaches only one Subject. (e.g., If Dr. Smith teaches “Ethical Hacking”, she cannot teach “Cryptography”). Rule C: A Subject can have multiple instructors. Rule D: A Student can take multiple subjects. The Sample Data Student Subject Instructor Alice Network Sec Prof. X Alice Crypto Prof. Y Bob Network Sec Prof. Z Bob Crypto Prof. Y   The Question Identify the Candidate Keys of the relation Session. What is the highest Normal Form this table currently satisfies (1NF, 2NF, 3NF, or BCNF)? Decompose the table into BCNF (if it isn’t already). After decomposition, demonstrate if we have lost any constraints (Dependency Preservation). Can we enforce “Rule A” purely using the Primary Keys of the new tables?

You are designing a database for a specialized hospital network. The Entities: Surgeons (ID, Name, Specialty) Patients (ID, Name, DOB) Surgeries (SurgeryCode, Description, RiskLevel) – Note: This is a type of surgery, e.g., “Appendectomy”, not a specific scheduled event. OperatingRooms (RoomID, Location) The Constraints: The Event: A specific surgery involves one Patient, one Surgeon, and one Surgery Type happening at a specific Date/Time. The Room Logic: That specific event happens in one Operating Room. The Critical Data Point: We need to record a “Success Rating” (1-10) and “Complication Notes”. Crucial Twist: The “Success Rating” is not just about the Surgeon, and not just about the Patient. It is a rating of how that specific Surgeon performed that specific Surgery on that specific Patient. Draw/Describe the ER Diagram. Specifically: How do you associate the OperatingRoom and the SuccessRatingwithout creating data redundancy or logical loops?