Varray Concepts - Quiz Explanation
The answers you selected are indicated below, along with text that explains the correct answers.
1.
In what forms can Oracle store a varray?
Please select the best answer.
A.
BLOB only
B.
Raw data only
C.
Both raw data and BLOB
D.
Neither raw data nor BLOB
Answer C is correct
How to store a varray is decided by Oracle, and it depends on the total size of the declared varray. If the total size does not exceed 4 KB, Oracle stores the varray as raw data. Otherwise, Oracle stores it as BLOB data. Hence, answer C is correct. Answer A is incorrect because Oracle can store a varray as either BLOB or raw data depending on the total size of the declared varray. Similarly, answer B and answer D are incorrect.
2.
What explains why it is more efficient to use a nested table than a varray?
Please select the best answer.
A.
A nested table allows you to update parts of the data, whereas updating parts of the data is not allowed within a varray.
B.
A varray allows you to update parts of the data, whereas updating parts of the data is not allowed within a nested table.
C.
Neither a varray nor a nested table allows you to update parts of the data.
D.
Both a varray and a nested table allow you to update parts of the data.
Answer A is correct.
Oracle allows you to update parts of the data within a nested table. However, this is not the case for a varray. Given this feature, it is more efficient to use a nested table than a varray. Thus, answer A is correct. Answer B is incorrect because the reverse is true; that is, a nested table allows you to update parts of the data, whereas updating part of the data is not allowed within a varray. For the same reasons, answer C and answer D are incorrect.
3.
If the application requires querying and modifying the entire collection, which collection, nested table or varray is the better alternative?
Please select the best answer.
A.
A nested table is the better alternative.
B.
It does not matter, you can use either.
C.
Neither are good alternatives.
D.
A varray is the better alternative.
Answer D is correct.
A nested table allows you to update parts of the data, whereas updating parts of the data is not allowed within a varray. Therefore, if the application requires querying and modifying the entire collection, a varray is the better alternative. Hence, answer D is correct. If the collection defined within the application is very large and you need to query and modify only a subset of the data stored within the collection, a nested table is a better choice. Hence, answer A is incorrect. It does matter what collection you use, so answer B is incorrect. Depending on the application, a nested table may be a better alternative over a varray or vice versa, so answer C is incorrect.
