Question 40 The relational data model is a. an external data model b. an interna
ID: 3710190 • Letter: Q
Question
Question 40
The relational data model is
a.
an external data model
b.
an internal data model
c.
a physical data model
d.
a logical data model
Question 49
Which of the following statement(s) is(are) correct?
a.
Multi-level index is designed to reduce the search cost of index part with a reduction ratio of logarithm function.
b.
Multi-level index is guaranteed to have the search cost proportional to the number of levels inmulti-level index.
c.
Both a. and b. are correct.
d.
Neither a. nor b. is correct.
Question 50
_____________________ guarantee(s) that the number of index block accesses is equal to the level of the index structures.
a.
Dynamic hashing
b.
Multilevel index
c.
B-tree/B+-tree
d.
Multi-Way search tree
Question 51
______________________ guarantee(s) the access structure is always balanced when a lot of updates such as insertions and deletions of file records occur.
a.
B-tree/B+-tree
b.
Multilevel index
c.
Multi-Way search tree
d.
Dynamic hashing
a.
an external data model
b.
an internal data model
c.
a physical data model
d.
a logical data model
Explanation / Answer
Answer 40: d) a logical data model
Because each table has keys and tables are connected through the keys. The data fields of the tables are not physically together, but they can be retrieved logically by connecting tables via keys.
Answer 49: c) both a. and b. are correct.
Answer 50: c) B-tree/B+-tree
Answer 51: d) Dynamic hashing
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