6Which data structure is most commonly used for database indexes?AB+ treeBStackCQueueDLinked listView AnswerDiscussWorkspaceReportSaveEasy
7A dense index has:AEntries only for NULLsBEntries for only some valuesCAn index entry for every search-key valueDNo entriesView AnswerDiscussWorkspaceReportSaveEasy
8A covering index is one that:AHas no keyBIs stored in memory onlyCContains all columns a query needs, so the table is not readDCovers every tableView AnswerDiscussWorkspaceReportSaveEasy
9Static hashing can suffer from:ALack of keysBOverflow chains when buckets fill upCToo many tree levelsDSorted outputView AnswerDiscussWorkspaceReportSaveEasy
10A composite index on (last_name, first_name) helps most with queries filtering on:Alast_name, or last_name and first_nameBfirst_name aloneCNeither columnDAny other columnView AnswerDiscussWorkspaceReportSaveEasy