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CREATE TABLE Faculties (
    FacultyID INT PRIMARY KEY,
    FacultyName NVARCHAR(100) NOT NULL
);

CREATE TABLE Departments (
    DepartmentID INT PRIMARY KEY,
    DepartmentName NVARCHAR(100) NOT NULL,
    FacultyID INT NOT NULL,
    FOREIGN KEY (FacultyID) REFERENCES Faculties(FacultyID)
);

CREATE TABLE Groups (
    GroupID INT PRIMARY KEY,
    GroupName NVARCHAR(20) NOT NULL,
    FacultyID INT NOT NULL,
    FOREIGN KEY (FacultyID) REFERENCES Faculties(FacultyID)
);

CREATE TABLE Students (
    StudentID INT PRIMARY KEY,
    LastName NVARCHAR(50) NOT NULL,
    FirstName NVARCHAR(50) NOT NULL,
    BirthDate DATE NOT NULL,
    GroupID INT NOT NULL,
    FOREIGN KEY (GroupID) REFERENCES Groups(GroupID)
);

CREATE TABLE Teachers (
    TeacherID INT PRIMARY KEY,
    LastName NVARCHAR(50) NOT NULL,
    FirstName NVARCHAR(50) NOT NULL,
    DepartmentID INT NOT NULL,
    FOREIGN KEY (DepartmentID) REFERENCES Departments(DepartmentID)
);

CREATE TABLE Subjects (
    SubjectID INT PRIMARY KEY,
    SubjectName NVARCHAR(100) NOT NULL,
    HoursPerWeek INT NOT NULL,
    DepartmentID INT NOT NULL,
    FOREIGN KEY (DepartmentID) REFERENCES Departments(DepartmentID)
);

CREATE TABLE Classrooms (
    ClassroomID INT PRIMARY KEY,
    ClassroomName NVARCHAR(20) NOT NULL,
    Capacity INT NOT NULL
);

CREATE TABLE Schedules (
    ScheduleID INT PRIMARY KEY,
    SubjectID INT NOT NULL,
    TeacherID INT NOT NULL,
    GroupID INT NOT NULL,
    ClassroomID INT NOT NULL,
    LessonDate DATE NOT NULL,
    FOREIGN KEY (SubjectID) REFERENCES Subjects(SubjectID),
    FOREIGN KEY (TeacherID) REFERENCES Teachers(TeacherID),
    FOREIGN KEY (GroupID) REFERENCES Groups(GroupID),
    FOREIGN KEY (ClassroomID) REFERENCES Classrooms(ClassroomID)
);

CREATE TABLE Enrollments (
    EnrollmentID INT PRIMARY KEY,
    StudentID INT NOT NULL,
    SubjectID INT NOT NULL,
    EnrollmentDate DATE NOT NULL,
    FOREIGN KEY (StudentID) REFERENCES Students(StudentID),
    FOREIGN KEY (SubjectID) REFERENCES Subjects(SubjectID)
);

CREATE TABLE Grades (
    GradeID INT PRIMARY KEY,
    StudentID INT NOT NULL,
    SubjectID INT NOT NULL,
    Grade INT NOT NULL,
    GradeDate DATE NOT NULL,
    FOREIGN KEY (StudentID) REFERENCES Students(StudentID),
    FOREIGN KEY (SubjectID) REFERENCES Subjects(SubjectID)
);
Students — студенты.
Teachers — преподаватели.
Subjects — предметы.
Grades — оценки.
Groups — учебные группы.
Faculties — факультеты или отделения.
Departments — кафедры или цикловые комиссии.
Classrooms — аудитории.
Schedules — расписание занятий.
Enrollments — зачисление студентов на предметы или курсы.Как это связать