Which of the following are in 3NF but not in BCNF?
Which of the following are in 3NF but not in BCNF?
A 3NF table that does not have multiple overlapping candidate keys is guaranteed to be in BCNF. In this case, candidate keys are (A,B)and (A,C). It meets 3NF because. the right-hand-side of all functional dependencies is a primary attribute.
What is the difference between 3NF and Bcnf explain with example?
This relation is in 3NF as it is already in 2NF and has no transitive dependency….Difference between 3NF and BCNF :
| S.NO. | 3NF | BCNF |
|---|---|---|
| 3. | In 3NF the functional dependencies are already in 1NF and 2NF. | In BCNF the functional dependencies are already in 1NF, 2NF and 3NF. |
| 4. | The redundancy is high in 3NF. | The redundancy is comparatively low in BCNF. |
Is 3NF always in BCNF?
Explanation: BCNF is a stronger version 3NF. So every relation in BCNF will also be in 3NF. Attention reader!
Which one is stronger BCNF or 3NF explain your answer with example?
BCNF is a stronger form of normalization than 3NF because it eliminates the second condition for 3NF, which allowed the right side of the FD to be a prime attribute. Thus, every left side of an FD in a table must be a superkey.
What is the difference between 3NF and 4NF?
It must be in Boyce Codd Normal Form (BCNF). It should have no multi-valued dependency….Difference between BCNF and 4NF :
| S.No. | BCNF | 4NF |
|---|---|---|
| 5 | If a relation is in BCNF then it will have more redundancy as compared to 4NF. | If a relation is in 4NF then it will have less redundancy as compared to BCNF . |
Which is better 3NF or BCNF?
BCNF is a stronger form of normalization than 3NF because it eliminates the second condition for 3NF, which allowed the right side of the FD to be a prime attribute. Thus, every left side of an FD in a table must be a superkey. Every table that is BCNF is also 3NF, 2NF, and 1NF, by the previous definitions.
Which of the following is true about 3NF and BCNF?
A relation R is in 3NF if every non-prime attribute of R is fully functionally dependent on every key of R but this does not guarantee transitive dependency. Every relation is BCNF must be in 3NF. Any relation can be in both BCNF & 3NF if it satisfies the condition of BCNF. Hence, the correct answer is “option 3”.
Why schema is not in BCNF but not 3NF?
Clearly the relation which contains the dependency that satisfies this 3rd condition can be in 3NF but not in BCNF. The book gives following example: Here, first FD is non trivial. Also i_ID is not a super key. Hence schema is not in BCNF. Now dept_name is a part of the candidate key ( s_ID,dept_name ). Hence, dept_advisor is in 3NF.
What is the difference between 3NF and BCNF?
DBMS Database Big Data Analytics BCNF (Boyce Codd Normal Form) is the advanced version of 3NF. A table is in BCNF if every functional dependency X->Y, X is the super key of the table. For BCNF, the table should be in 3NF, and for every FD.
How to determine if a table is in BCNF?
A table is in BCNF if every functional dependency X->Y, X is the super key of the table. For BCNF, the table should be in 3NF, and for every FD. LHS is super key. Consider a relation R with attributes (student, subject, teacher). Candidate keys are (student, teacher) and (student, subject).
Why teacher is not a key in BCNF?
The above relation is not in BCNF, because in the FD (teacher->subject), teacher is not a key. This relation suffers with anomalies − For example, if we try to delete the student Subbu, we will lose the information that R. Prasad teaches C. These difficulties are caused by the fact the teacher is determinant but not a candidate key.