我正在 Build 一个数据库注册类,我在“注册”表中遇到问题 . 我需要将所有主键从部分传递到注册,但我还想传递一个额外的键(“sectionNumber”) . 但是,我不想让“sectionNumber”成为“Sections”主键的一部分,因为我不想将sectionNumber传递给每个具有外键的表,而是来自“Sections” . 任何人都有任何关于如何解决此问题的建议?我一直收到以下错误 .
-- HOLDS A SPECIFIC COURSE WITHOUT THE INSTANCES OF THE CLASS --
CREATE TABLE Courses (
courseID SERIAL UNIQUE NOT NULL,
department TEXT NOT NULL,
courseNumber VARCHAR(10) NOT NULL,
courseName TEXT UNIQUE NOT NULL,
credits INT NOT NULL,
PRIMARY KEY(courseID)
);
-- PEOPLE SUPERTYPE --
CREATE TABLE People (
pid SERIAL UNIQUE NOT NULL,
fname TEXT NOT NULL,
lname TEXT NOT NULL,
PRIMARY KEY(pid)
);
-- HOLDS THE DIFFERENT PROFESSORS TEACHING AT THE SCHOOL --
-- SUBTYPE OF PEOPLE --
CREATE TABLE Professors (
professorID INT UNIQUE NOT NULL,
status TEXT NOT NULL,
CHECK(status = 'Full-Time' OR status = 'Part-time'),
PRIMARY KEY(professorID),
FOREIGN KEY(professorID) REFERENCES People(pid)
);
-- HOLDS THE SPECIFIC INSTANCES OF THE CLASS DEPENDING ON THE YEAR AND TERM --
CREATE TABLE Sections (
courseID INT NOT NULL,
year INT NOT NULL,
term TEXT NOT NULL,
sectionNumber INT NOT NULL,
startDate DATE NOT NULL,
endDate DATE NOT NULL,
crn INT NOT NULL,
CHECK(term = 'Fall' OR term = 'Winter' OR term = 'Spring' OR term = 'Summer'),
PRIMARY KEY(courseID, year, term),
FOREIGN KEY(courseID) REFERENCES Courses(courseID)
);
-- HOLDS THE EVENT OF THE CLASS --
-- A CLASS MAY HAVE DIFFERENT DAYS ON WHICH --
-- THEY MEET ON, SO THIS ALLOWS A CERTAIN --
-- SECTION TO HAVE SEVERAL DAYS WITHOUT CONFLICT --
CREATE TABLE ClassEvent (
professorID INT UNIQUE NOT NULL,
courseID INT NOT NULL,
year INT NOT NULL,
term TEXT NOT NULL,
day TEXT,
startTime TIME,
endTime TIME,
location TEXT,
campus TEXT,
CHECK(day = 'Monday' OR day = 'Tuesday' OR day = 'Wednesday' OR day = 'Thursday' OR day = 'Friday' OR day = 'Saturday' OR day = 'Sunday' OR day IS NULL),
CHECK(term = 'Fall' OR term = 'Winter' OR term = 'Spring' OR term = 'Summer'),
PRIMARY KEY(professorID, courseID, year, term, day, startTime, endTime),
FOREIGN KEY(professorID) REFERENCES Professors(professorID),
FOREIGN KEY(courseID, year, term) REFERENCES Sections(courseID, year, term)
);
-- GENERATES THE PREREQUESITES --
CREATE TABLE Prerequisites (
courseID INT NOT NULL,
year INT NOT NULL,
term TEXT NOT NULL,
prereqID INT NOT NULL,
CHECK(term = 'Fall' OR term = 'Winter' OR term = 'Spring' OR term = 'Summer'),
PRIMARY KEY(courseID, year, term, prereqID),
FOREIGN KEY(courseID, year, term) REFERENCES Sections(courseID, year, term),
FOREIGN KEY(prereqID) REFERENCES Courses(courseID)
);
-- HOLDS THE STUDENTS THAT WILL BE TAKING THE CLASSES --
-- SUBTYPE OF PEOPLE --
CREATE TABLE Students (
studentID INT REFERENCES People(pid) UNIQUE NOT NULL,
studentName TEXT NOT NULL,
gradYear DATE UNIQUE NOT NULL,
PRIMARY KEY(studentID)
);
-- HOLDS A CLASS RECORD FOR STUDENTS (AND POSSIBLY PROFESSORS) --
CREATE TABLE Enrollment (
studentID INT UNIQUE NOT NULL,
courseID INT NOT NULL,
year INT NOT NULL,
term TEXT NOT NULL,
sectionNumber INT NOT NULL,
grade TEXT,
CHECK(grade = 'A' OR grade = 'A-' OR grade = 'B+' OR grade = 'B' OR grade = 'B-' OR grade = 'C+' OR grade = 'C' OR grade = 'C-' OR grade = 'D+' OR grade = 'D' OR grade = 'D-' OR grade = 'F' OR grade = 'P/F'),
CHECK(term = 'Fall' OR term = 'Winter' OR term = 'Spring' OR term = 'Summer'),
PRIMARY KEY(studentID, courseID, year, term, sectionNumber),
FOREIGN KEY(studentID) REFERENCES Students(studentID),
FOREIGN KEY(courseID, year, term) REFERENCES Sections(courseID, year, term),
FOREIGN KEY(sectionNumber) REFERENCES Sections(sectionNumber)
);
-- HOLDS THE DIFFERENT DEGREES THAT CAN BE ATTAINED AT THE COLLEGE/UNIVERSITY --
CREATE TABLE Degrees (
degreeID SERIAL UNIQUE NOT NULL,
degreeName TEXT NOT NULL,
degreeType TEXT NOT NULL,
degDepartment VARCHAR(4) NOT NULL,
CHECK(degreeType = 'Major' OR degreeType = 'Minor' OR degreeType = 'Masters'),
PRIMARY KEY(degreeID)
);
-- HOLDS THE CLASSES THAT WILL MAKE UP A DEGREE --
CREATE TABLE DegreeReq (
degreeID INT REFERENCES Degrees(degreeID) UNIQUE NOT NULL,
courseID INT REFERENCES Courses(courseID) NOT NULL,
PRIMARY KEY(degreeID, courseID)
);
-- HOLDS THE INSTANCE OF A DEGREE FOR A CERTAIN STUDENT --
-- FOR EXAMPLE: A STUDENT CAN HAVE A MAJOR AND A MINOR --
-- SO HE/SHE CAN STORE THEM SEPARATELY --
CREATE TABLE DegreeInstance (
degreeID INT REFERENCES Degrees(degreeID) UNIQUE NOT NULL,
studentID INT REFERENCES Students(studentID) UNIQUE NOT NULL,
startDate DATE NOT NULL,
endDate DATE NOT NULL,
creditsRequired INT NOT NULL,
PRIMARY KEY(degreeID, studentID)
);
-- HOLDS ALL THE RATE MY PROFESSOR STATS --
CREATE TABLE Rating (
professorID INT UNIQUE NOT NULL,
rmpID BIGINT UNIQUE NOT NULL,
avgRating FLOAT NOT NULL,
avgHelpfulness FLOAT NOT NULL,
avgClarity FLOAT NOT NULL,
avgEasiness FLOAT NOT NULL,
PRIMARY KEY(professorID, rmpID),
FOREIGN KEY(professorID) REFERENCES Professors(professorID)
);
ERROR: there is no unique constraint matching given keys for referenced table "sections"
********** Error **********
ERROR: there is no unique constraint matching given keys for referenced table "sections"
SQL state: 42830
1 回答
你宣布了这种关系:
sectionnumber
未声明为唯一 . 您需要修复数据结构或使用主键 .