Table Students {
    id integer [pk, increment, not null, unique, note: 'Номер студенческого билета']
    person_id integer [not null, unique, note: 'Номер физического лица']
    group varchar [not null, note: 'Номер учебной группы']
    supervisor integer [note: 'Номер научного руководителя']
    education_form varchar [not null, default: 'Очная', note: 'Форма обучения студента']
    status varchar [not null, default: 'Учится', note: 'Статус обучающегося']
}

Table Persons {
    id integer [pk, increment, not null, unique]
    name varchar [not null]
    surname varchar [not null]
    birthday timestamp [not null]
    phone varchar [not null]
    mail varchar [default: null]
    passport_no varchar [not null]
    citizenship varchar [not null]
    address varchar [not null]
    access_card varchar [not null]
    access_level varchar [not null]
}

Table Groups {
    group varchar [pk, not null, unique]
    faculty_id integer [not null]
    program_id integer [not null]
    department_id integer [not null]
    study_starts timestamp [not null]
    study_ends timestamp [not null]
}

Table Family {
    id integer [pk, increment, not null, unique]
    student_id integer [not null]
    name varchar [not null]
    surname varchar [not null]
    kinship varchar [not null, note: 'Степень родства: mthr, fthr, brth, sstr']
    phone varchar [not null]
    address varchar [not null]
}

Table Files {
    id integer [pk, increment, not null, unique]
    student_id integer [not null]
    name varchar [not null]
    description varchar [not null]
    extension varchar [not null, note: 'available: png, jpeg, pdf']
    size numeric [not null, note: 'size in mb']
    path varchar [not null, note: 'path to file /var/www/student_files/<file_id>.<ext>']
    loaded_at timestamp [not null]
}

Table Supervisors {
    id integer [pk, increment, not null, unique]
    person_id integer [not null]
    experience integer [not null]
    defended_ratio real [not null]
    qualification varchar [not null]
}

Table Movement {
    id integer [pk, increment, not null, unique]
    student_id integer [not null]
    type varchar [not null]
    new_group varchar
    new_status varchar
    issued_at timestamp [not null]
}

Table Departments {
    id integer [pk, increment, not null, unique]
    name varchar [not null]
    acronym varchar [not null]
    founded timestamp [not null]
    head integer [not null]
    vice integer
    secretary integer
    faculty_id integer
}

Table Programs {
    id integer [pk, increment, not null, unique]
    specification varchar [not null, note: 'Key from Russian register']
    degree varchar [not null]
    name varchar [not null]
    parent_id integer [not null]
}

Table Faculties {
    id integer [pk, increment, not null, unique]
    name varchar [not null]
    acronym varchar [not null]
    head integer [not null]
    vice integer
    address varchar [not null]
}

Table Statements {
    id integer [pk, increment, not null, unique]
    student_id integer [not null]
    discipline_id integer [not null]
    examiner_id integer [not null]
    try_no integer [not null]
    grade integer [not null]
    conducted_at timestamp [not null]
}

Table Disciplines {
    id integer [pk, increment, not null, unique]
    name varchar [not null]
    department_id integer [not null]
    credit_units integer [not null]
    academic_hours integer [not null]
    general_hours integer [not null]
    is_annual boolean [not null]
}

Ref "Студент к физлицу" {
    Persons.id - Students.person_id [delete: no action]
}

Ref "Загружен для" {
    Files.student_id > Students.id [delete: no action]
}

Ref "Руководитель к физлицу" {
    Departments.head - Persons.id [delete: no action]
}

Ref "Заместитель к физлицу" {
    Departments.vice - Persons.id [delete: no action]
}

Ref "Секретарь к физлицу" {
    Departments.secretary - Persons.id [delete: no action]
}

Ref "К научному руководителю" {
    Students.supervisor > Supervisors.id [delete: no action]
}

Ref "В учебной группе" {
    Students.group > Groups.group [delete: no action]
}

Ref "План/программа группы" {
    Groups.program_id > Programs.id [delete: no action]
}

Ref "Группа факультета" {
    Groups.faculty_id > Faculties.id [delete: no action]
}

Ref "Имеет базовую кафедру" {
    Groups.department_id > Departments.id [delete: no action]
}

Ref "Ведомость по студенту" {
    Statements.student_id > Students.id [delete: no action]
}

Ref "Ведомость по дисциплине" {
    Statements.discipline_id > Disciplines.id [delete: no action]
}

Ref "Экзаменатор к физлицу" {
    Statements.examiner_id > Persons.id [delete: no action]
}

Ref "Дисциплина к кафедре" {
    Disciplines.department_id > Departments.id [delete: no action]
}

Ref "Подразделение факультета" {
    Departments.faculty_id > Faculties.id [delete: no action]
}

Ref "Приказ по студенту" {
    Movement.student_id > Students.id [delete: no action]
}

Ref "Научный руководитель к физлицу" {
    Supervisors.person_id - Persons.id [delete: no action]
}

Ref "Дочерний к программе" {
    Programs.parent_id - Programs.id [delete: no action]
}

Ref "Родственник студента" {
    Family.student_id > Students.id [delete: no action]
}