關係代數:σ π × ÷ ∪ ∩ − ⋈(⟗ ⟕ ⟖)

顯示效果:

σsno=1(Student)\sigma_{sno = 1}(Student)
σsno=1(Student)
σsno=1sage>18ssex="F"(Student)\sigma_{sno = 1 \wedge sage >18 \vee ssex="F"}(Student)
σsno=1∧sage>18∨ssex=“F” (Student)
Πsno,cno(Student)\Pi_{sno,cno}(Student)
πsno,cno (Student)
StudentSCStudent \Join SC
StudentSCStudent \bowtie SC
Student⋈SC
StudentStudent.Sno=SC.SnoSCStudent \underset{Student.Sno=SC.Sno}\Join SC
Student ⟗ SC
Student ⟕ SC
Student ⟖ SC
Student×SCStudent \times SC
Student × SC
SC÷KSC \div K
SC ÷ K
RSR \cup S
R∪S
RSR \cap S
R∩S
RSR - S
R−S
ΠSname(Πsno(σCpno=5(Course)SC)ΠSno,Sname(Student))\Pi_{Sname}(\Pi_{sno}(\sigma_{Cpno='5'}(Course)\Join SC)\Join \Pi_{Sno,Sname}(Student))
πSnamesnoCpno=′5′(Course) ⋈ SC) ⋈ π Sno,Sname (Student))

對應的代碼:

$\sigma_{sno = 1}(Student)$
σ~sno=1~(Student)
$\sigma_{sno = 1 \wedge sage >18 \vee ssex="F"}(Student)$
σ~sno=1∧sage>18∨ssex="F"~ (Student)
$\Pi_{sno,cno}(Student)$
π~sno,cno~ (Student)
$Student \Join SC$
$Student \bowtie SC$
Student⋈SC
$Student \underset{Student.Sno=SC.Sno}\Join  SC$
Student ⟗ SC
Student ⟕ SC
Student ⟖ SC
$Student \times SC$
Student × SC
$SC \div K$
SC ÷ K
$R \cup S$
R∪S
$R \cap S$
R∩S
$R - S$
R−S
$\Pi_{Sname}(\Pi_{sno}(\sigma_{Cpno='5'}(Course)\Join SC)\Join \Pi_{Sno,Sname}(Student))$
π~Sname~ (π~sno~ (σ~Cpno=′5′~(Course) ⋈ SC) ⋈ π ~Sno,Sname~ (Student))
發表評論
所有評論
還沒有人評論,想成為第一個評論的人麼? 請在上方評論欄輸入並且點擊發布.
相關文章