Which is generally fastest for locating a record: a) a dense index, b) a sparse

Question

Which is generally fastest for locating a record: a) a dense index, b) a sparse index, or c) both are equally fast? _____________

Suppose we have a dense index on a table, and a row of the table is deleted. To keep the index up to date, how many rows of the index will need to be deleted? a) none, b) 0 or 1, depending on the table, or c) at least 1? _____________

What combination can’t be used? a) dense, clustering indexes, b) dense, non-clustering indexes, c) sparse, clustering indexes or d) sparse, non-clustering indexes? ________

In section 11.2.4 of the text, the authors state that an index is normally created by default for the primary key of a table, and that the index is used when a new record is inserted to ensure uniqueness of the primary key value. How would this uniqueness check be performed? a) the primary key values of table records would be compared to rows of the index, b) a linear scan would be made of the index, or c) a binary search would be made of the index. _______

Explanation / Answer

Answer:

Which is generally fastest for locating a record: a) a dense index, b) a sparse index, or c) both are equally fast?

a) a dense index

Suppose we have a dense index on a table, and a row of the table is deleted. To keep the index up to date, how many rows of the index will need to be deleted? a) none, b) 0 or 1, depending on the table, or c) at least 1? a)none

What combination can’t be used? a) dense, clustering indexes, b) dense, non-clustering indexes, c) sparse, clustering indexes or d) sparse, non-clustering indexes? a) dense, clustering indexes

In section 11.2.4 of the text, the authors state that an index is normally created by default for the primary key of a table, and that the index is used when a new record is inserted to ensure uniqueness of the primary key value. How would this uniqueness check be performed? a) the primary key values of table records would be compared to rows of the index, b) a linear scan would be made of the index, or c) a binary search would be made of the index. b) a linear scan would be made of the index

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