diff --git a/advlabdb/models.py b/advlabdb/models.py
index b9f9095..a8157ae 100644
--- a/advlabdb/models.py
+++ b/advlabdb/models.py
@@ -44,7 +44,7 @@ class Student(db.Model):
     bachelor_thesis_work_group = db.Column(db.String, nullable=True)
     note = db.Column(db.Text, nullable=True)
 
-    part_students = db.relationship("PartStudent", backref="student", lazy=True)
+    part_students = db.relationship("PartStudent", back_populates="student", lazy=True)
 
     def repr(self):
         return f"{self.first_name} {self.last_name}"
@@ -63,10 +63,13 @@ class PartStudent(db.Model):
     )
 
     student_id = db.Column(db.Integer, db.ForeignKey("student.id"), nullable=False)
+    student = db.relationship("Student", back_populates="part_students")
     part_id = db.Column(db.Integer, db.ForeignKey("part.id"), nullable=False)
+    part = db.relationship("Part", back_populates="part_students")
     group_id = db.Column(db.Integer, db.ForeignKey("group.id"), nullable=True)
+    group = db.relationship("Group", back_populates="part_students")
 
-    experiment_marks = db.relationship("ExperimentMark", backref="part_student", lazy=True)
+    experiment_marks = db.relationship("ExperimentMark", back_populates="part_student", lazy=True)
 
     __table_args__ = (
         db.UniqueConstraint(student_id, part_id),
@@ -142,10 +145,12 @@ class Group(db.Model):
     number = db.Column(db.Integer, db.CheckConstraint(f"number >= {MIN_GROUP_NUMBER}"), nullable=False)
 
     semester_id = db.Column(db.Integer, db.ForeignKey("semester.id"), nullable=False)
+    semester = db.relationship("Semester", back_populates="groups")
     program_id = db.Column(db.Integer, db.ForeignKey("program.id"), nullable=False)
+    program = db.relationship("Program", back_populates="groups")
 
-    part_students = db.relationship("PartStudent", backref="group", lazy=True)
-    group_experiments = db.relationship("GroupExperiment", backref="group", lazy=True)
+    part_students = db.relationship("PartStudent", back_populates="group", lazy=True)
+    group_experiments = db.relationship("GroupExperiment", back_populates="group", lazy=True)
 
     __table_args__ = (db.UniqueConstraint(number, semester_id, program_id),)
 
@@ -195,10 +200,12 @@ class GroupExperiment(db.Model):
     id = db.Column(db.Integer, primary_key=True)
 
     semester_experiment_id = db.Column(db.Integer, db.ForeignKey("semester_experiment.id"), nullable=False)
+    semester_experiment = db.relationship("SemesterExperiment", back_populates="group_experiments")
     group_id = db.Column(db.Integer, db.ForeignKey("group.id"), nullable=False)
+    group = db.relationship("Group", back_populates="group_experiments")
 
-    appointments = db.relationship("Appointment", backref="group_experiment", lazy=True)
-    experiment_marks = db.relationship("ExperimentMark", backref="group_experiment", lazy=True)
+    appointments = db.relationship("Appointment", back_populates="group_experiment", lazy=True)
+    experiment_marks = db.relationship("ExperimentMark", back_populates="group_experiment", lazy=True)
 
     __table_args__ = (db.UniqueConstraint(semester_experiment_id, group_id),)
 
@@ -242,8 +249,9 @@ class Experiment(db.Model):
     active = db.Column(db.Boolean, default=True, nullable=False)
 
     program_id = db.Column(db.Integer, db.ForeignKey("program.id"), nullable=False)
+    program = db.relationship("Program", back_populates="experiments")
 
-    semester_experiments = db.relationship("SemesterExperiment", backref="experiment", lazy=True)
+    semester_experiments = db.relationship("SemesterExperiment", back_populates="experiment", lazy=True)
 
     __table_args__ = (db.UniqueConstraint(number, program_id),)
 
@@ -285,12 +293,14 @@ class SemesterExperiment(db.Model):
     )
 
     experiment_id = db.Column(db.Integer, db.ForeignKey("experiment.id"), nullable=False)
+    experiment = db.relationship("Experiment", back_populates="semester_experiments")
     semester_id = db.Column(db.Integer, db.ForeignKey("semester.id"), nullable=False)
+    semester = db.relationship("Semester", back_populates="semester_experiments")
 
     assistants = db.relationship(
-        "Assistant", secondary=experiment_assistant, lazy=True, backref=db.backref("semester_experiments", lazy=True)
+        "Assistant", secondary=experiment_assistant, back_populates="semester_experiments", lazy=True
     )
-    group_experiments = db.relationship("GroupExperiment", backref="semester_experiment", lazy=True)
+    group_experiments = db.relationship("GroupExperiment", back_populates="semester_experiment", lazy=True)
 
     __table_args__ = (db.UniqueConstraint(experiment_id, semester_id),)
 
@@ -328,9 +338,13 @@ class Assistant(db.Model):
     id = db.Column(db.Integer, primary_key=True)
 
     user_id = db.Column(db.Integer, db.ForeignKey("user.id"), nullable=False, unique=True)
+    user = db.relationship("User", back_populates="assistant")
 
-    appointments = db.relationship("Appointment", backref="assistant", lazy=True)
-    experiment_marks = db.relationship("ExperimentMark", backref="assistant", lazy=True)
+    semester_experiments = db.relationship(
+        "SemesterExperiment", secondary=experiment_assistant, back_populates="assistants", lazy=True
+    )
+    appointments = db.relationship("Appointment", back_populates="assistant", lazy=True)
+    experiment_marks = db.relationship("ExperimentMark", back_populates="assistant", lazy=True)
 
     def repr(self):
         return f"{self.user.first_name} {self.user.last_name}"
@@ -343,8 +357,9 @@ class Admin(db.Model):
     id = db.Column(db.Integer, primary_key=True)
 
     user_id = db.Column(db.Integer, db.ForeignKey("user.id"), nullable=False, unique=True)
+    user = db.relationship("User", back_populates="admin")
 
-    experiment_marks = db.relationship("ExperimentMark", backref="admin", lazy=True)
+    experiment_marks = db.relationship("ExperimentMark", back_populates="admin", lazy=True)
 
     def repr(self):
         return f"{self.user.first_name} {self.user.last_name}"
@@ -359,7 +374,9 @@ class Appointment(db.Model):
     special = db.Column(db.Boolean, default=False, nullable=False)  # In the break or not
 
     group_experiment_id = db.Column(db.Integer, db.ForeignKey("group_experiment.id"), nullable=False)
+    group_experiment = db.relationship("GroupExperiment", back_populates="appointments")
     assistant_id = db.Column(db.Integer, db.ForeignKey("assistant.id"), nullable=False)
+    assistant = db.relationship("Assistant", back_populates="appointments")
 
     def checkAndGetAssistant(groupExperiment, assistant=None):
         semesterExperiment = groupExperiment.semester_experiment
@@ -403,9 +420,11 @@ class Part(db.Model):
     number = db.Column(db.Integer, db.CheckConstraint(f"number >= {MIN_PART_NUMBER}"), nullable=False)
 
     program_id = db.Column(db.Integer, db.ForeignKey("program.id"), nullable=False)
+    program = db.relationship("Program", back_populates="parts")
     semester_id = db.Column(db.Integer, db.ForeignKey("semester.id"), nullable=False)
+    semester = db.relationship("Semester", back_populates="parts")
 
-    part_students = db.relationship("PartStudent", backref="part", lazy=True)
+    part_students = db.relationship("PartStudent", back_populates="part", lazy=True)
 
     __table_args__ = (db.UniqueConstraint(program_id, number, semester_id),)
 
@@ -421,10 +440,10 @@ class Semester(db.Model):
     label = db.Column(db.String(10), db.CheckConstraint("label IN ('WS', 'SS')"), nullable=False)
     year = db.Column(db.Integer, db.CheckConstraint(f"year BETWEEN {MIN_YEAR} AND {MAX_YEAR}"), nullable=False)
 
-    parts = db.relationship("Part", backref="semester", lazy=True)
-    semester_experiments = db.relationship("SemesterExperiment", backref="semester", lazy=True)
-    active_users = db.relationship("User", backref="active_semester", lazy=True)
-    groups = db.relationship("Group", backref="semester", lazy=True)
+    parts = db.relationship("Part", back_populates="semester", lazy=True)
+    semester_experiments = db.relationship("SemesterExperiment", back_populates="semester", lazy=True)
+    active_users = db.relationship("User", back_populates="active_semester", lazy=True)
+    groups = db.relationship("Group", back_populates="semester", lazy=True)
 
     __table_args__ = (db.UniqueConstraint(label, year),)
 
@@ -504,11 +523,15 @@ class ExperimentMark(db.Model):
     )
 
     part_student_id = db.Column(db.Integer, db.ForeignKey("part_student.id"), nullable=False)
+    part_student = db.relationship("PartStudent", back_populates="experiment_marks")
     group_experiment_id = db.Column(db.Integer, db.ForeignKey("group_experiment.id"), nullable=False)
+    group_experiment = db.relationship("GroupExperiment", back_populates="experiment_marks")
     assistant_id = db.Column(
         db.Integer, db.ForeignKey("assistant.id"), nullable=True
     )  # The last assistant who edited the mark
+    assistant = db.relationship("Assistant", back_populates="experiment_marks")
     admin_id = db.Column(db.Integer, db.ForeignKey("admin.id"), nullable=True)  # The last admin who edited the mark
+    admin = db.relationship("Admin", back_populates="experiment_marks")
 
     __table_args__ = (db.UniqueConstraint(part_student_id, group_experiment_id),)
 
@@ -548,9 +571,10 @@ class User(db.Model, FsUserMixin):
     room = db.Column(db.String(100), nullable=True)
 
     active_semester_id = db.Column(db.Integer, db.ForeignKey("semester.id"), nullable=True)
+    active_semester = db.relationship("Semester", back_populates="active_users")
 
-    admin = db.relationship("Admin", backref="user", lazy=False, uselist=False)
-    assistant = db.relationship("Assistant", backref="user", lazy=True, uselist=False)
+    admin = db.relationship("Admin", back_populates="user", lazy=False, uselist=False)
+    assistant = db.relationship("Assistant", back_populates="user", lazy=True, uselist=False)
 
     def repr(self):
         return f"{self.first_name} {self.last_name}"
@@ -571,9 +595,9 @@ class Program(db.Model):
     id = db.Column(db.Integer, primary_key=True)
     label = db.Column(db.String(25), nullable=False, unique=True)
 
-    parts = db.relationship("Part", backref="program", lazy=True)
-    experiments = db.relationship("Experiment", backref="program", lazy=True)
-    groups = db.relationship("Group", backref="program", lazy=True)
+    parts = db.relationship("Part", back_populates="program", lazy=True)
+    experiments = db.relationship("Experiment", back_populates="program", lazy=True)
+    groups = db.relationship("Group", back_populates="program", lazy=True)
 
     def repr(self):
         return f"{self.label}"