Which of the following statements is correct according to the following instance of the relational schema R(X, Y, Z)?
| X | Y | Z |
|---|---|---|
| 1 | 1 | a |
| 1 | 1 | a |
| 2 | 1 | b |
| 3 | 2 | b |
Pick an option to check yourself, or open the answer below.
Show answer & explanation
Correct answer: C. X → Y, X → Z
Explanation
Each X value (1, 2, 3) has one Y and one Z, so X → Y and X → Z hold. Y = 1 has Z = a and b (Y → Z fails) and X = 1, 2 (Y → X fails). Z = b has X = 2 and 3 (Z → X fails).More Database Management Systems questions
- What are the drawbacks of using file systems to store data? 1. Data inconsistency 2. Difficulty in accessing data 3. Data isolation 4. Atom…
- In which of the following database models do we have a parent-child relationship? 1. Hierarchical databases 2. Network databases 3. Relatio…
- Identify the correct operation that produces the given output from the two relations R1 and R2.R1 Name Class a1 9 b1 5 c1 6 d1 11 R2 Name C…
- Match List I with List II. Choose the correct answer from the options given below:List I List II a. Apache Kafka I. Platform for constructi…
- Select the correct order of the DBSCAN algorithm. I. Recursively find all density-connected points and assign them to the same cluster as t…
- Which relational algebra query computes the sids of sailors with age over 20 who have not reserved a red boat?