Which two statements are true about a bitmap index? ()

A . It is recommended for the columns that have unique values. B . It can be converted to a B-tree index by using the ALTER INDEX command. C . It has a bitmap segment for each distinct value in the key column, containing a string of bits in which each bit represents the presence or absence of a key column value. D . Updating the key column locks the whole bitmap segment that contains the bit for the key value to be updated.

时间:2022-10-06 16:52:10 所属题库:1Z0-042题库

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