diff --git a/apps/backend/app/models/experience.py b/apps/backend/app/models/experience.py
index cf4ae3d..ee2cfc8 100644
--- a/apps/backend/app/models/experience.py
+++ b/apps/backend/app/models/experience.py
@@ -18,7 +18,8 @@ class Experience(Base):
     id = Column(
         Integer,
         primary_key=True,
-        index=True
+        index=True,
+        nullable=False
     )
 
     company = Column(
diff --git a/apps/backend/app/models/experience_link.py b/apps/backend/app/models/experience_link.py
index 2742724..37fbc84 100644
--- a/apps/backend/app/models/experience_link.py
+++ b/apps/backend/app/models/experience_link.py
@@ -16,22 +16,23 @@ class ExperienceLink(Base):
     id = Column(
         Integer,
         primary_key=True,
-        index=True
+        index=True,
+        nullable=False
     )
 
     label = Column(
         String(255),
-        nullable=False
+        nullable=True
     )
 
     link = Column(
         String(255),
-        nullable=False
+        nullable=True
     )
 
     icon_path = Column(
         String(255),
-        nullable=False
+        nullable=True
     )
 
     experience_id = Column(
diff --git a/apps/backend/app/models/experience_task.py b/apps/backend/app/models/experience_task.py
index ee854db..dbee9aa 100644
--- a/apps/backend/app/models/experience_task.py
+++ b/apps/backend/app/models/experience_task.py
@@ -16,12 +16,13 @@ class ExperienceTask(Base):
     id = Column(
         Integer,
         primary_key=True,
-        index=True
+        index=True,
+        nullable=False
     )
 
     description = Column(
         String(255),
-        nullable=False
+        nullable=True
     )
 
     experience_id = Column(
diff --git a/apps/backend/app/models/project.py b/apps/backend/app/models/project.py
index 43a7937..a28627b 100644
--- a/apps/backend/app/models/project.py
+++ b/apps/backend/app/models/project.py
@@ -15,7 +15,12 @@ from app.models.project_skill import project_skills
 class Project(Base):
     __tablename__ = "projects"
 
-    id = Column(Integer, primary_key=True, index=True)
+    id = Column(
+        Integer,
+        primary_key=True,
+        index=True,
+        nullable=False
+    )
 
     title = Column(
         String(255),
@@ -24,7 +29,8 @@ class Project(Base):
 
     nb_image = Column(
         Integer,
-        default=1
+        default=1,
+        nullable=True
     )
 
     short_description = Column(
diff --git a/apps/backend/app/models/project_skill.py b/apps/backend/app/models/project_skill.py
index c048a15..31b7865 100644
--- a/apps/backend/app/models/project_skill.py
+++ b/apps/backend/app/models/project_skill.py
@@ -10,13 +10,15 @@ project_skills = Table(
         "project_id",
         Integer,
         ForeignKey("projects.id", ondelete="CASCADE"),
-        primary_key=True
+        primary_key=True,
+        nullable=False
     ),
 
     Column(
         "skill_id",
         Integer,
         ForeignKey("skills.id", ondelete="CASCADE"),
-        primary_key=True
+        primary_key=True,
+        nullable=False
     )
 )
\ No newline at end of file
diff --git a/apps/backend/app/models/skill.py b/apps/backend/app/models/skill.py
index 5bd83c7..79ee425 100644
--- a/apps/backend/app/models/skill.py
+++ b/apps/backend/app/models/skill.py
@@ -8,7 +8,12 @@ from app.models.project_skill import project_skills
 class Skill(Base):
     __tablename__ = "skills"
 
-    id = Column(Integer, primary_key=True, index=True)
+    id = Column(
+        Integer,
+        primary_key=True,
+        index=True,
+        nullable=False
+    )
 
     name = Column(
         String(255),