6If relation R has 4 tuples and S has 3 tuples, how many tuples are in R × S?A7B12C3D4View AnswerDiscussWorkspaceReportSaveMedium
7A super key is:AA foreign key in another tableBThe largest attributeCA key with exactly one attributeDAny set of attributes that uniquely identifies tuplesView AnswerDiscussWorkspaceReportSaveEasy
8Which constraint ensures a column's values are all different, while still allowing NULL in most DBMSs?ADEFAULTBUNIQUECCHECKDPRIMARY KEYView AnswerDiscussWorkspaceReportSaveEasy
9Which relational algebra operation selects rows that satisfy a condition?ACartesian product (×)BProjection (π)CUnion (∪)DSelection (σ)View AnswerDiscussWorkspaceReportSaveEasy
10A minimal set of attributes that uniquely identifies each tuple is a:AForeign keyBComposite attributeCCandidate keyDSuper keyView AnswerDiscussWorkspaceReportSaveEasy