• 2022-06-11
    设有如图2.27所示的3个关系R,S和W,写出如下4个元组演算表达式的结果。[img=574x242]17e2df117ee28d3.png[/img](1)[tex=10.5x1.357]V12q+5vCcawawArkId85R6dSttwjKZ8ZZakg7dj1ZHi1rV4dixK509SWIFTQPoixZ/qr7F3rjayXfprOk8ShIg==[/tex](2)[tex=9.0x1.357]cuMEun721XJPf4SsEq9Xi0c7nJ14BXXUJbPWxo2ET4k8pdnpKsx25RKPqOxSjoDJ[/tex](3)[tex=17.714x1.357]MHpHt+kncrZSPpwFpM8mYvaC/oNeOdcfrFGCWTpD/GQxu0FXADRFMuS+dGfDqrQW17ZayacBNfVHpKXNijQPee748Aai9yV4PBFzjbOBMpE=[/tex](4)[tex=37.857x1.357]9qYBRbTKoK2oXqLzEiaaphwB0jcoNqBmn8oFl3aziAYLkKbWWd7Esry99g9rXU/OnFNiDKBlDS/HTWr+tQW3ssD9iNehsO1XpX5O5RAV2mqkBvszAyjmEFyrBHLtlJn6JxrCpSj5tbQ9W1ZSU2xbhilReCqSKEUG8ipEYrOrPH7k1SeViHRtSi1MvHCC+m0kmlXVV55aMpwuxECYsPVlJGhxbWOfpLzgv/NUREHxKRs=[/tex]