diff --git a/app/models.py b/app/models.py
index 49ab7c8..eccd771 100644
--- a/app/models.py
+++ b/app/models.py
@@ -1,5 +1,20 @@
 from app import db
 
+Ressources_ACs = db.Table("Ressources_ACs",
+    db.Column("Ressource_code", db.String(4), db.ForeignKey("ressource.code")),
+    db.Column("AC_code", db.String(6), db.ForeignKey("AC.code"))
+)
+
+Ressources_SAEs = db.Table("Ressources_SAEs",
+    db.Column("Ressource_code", db.String(4), db.ForeignKey("ressource.code")),
+    db.Column("SAE_code", db.String(5), db.ForeignKey("SAE.code"))
+)
+
+SAEs_ACs = db.Table("SAEs_ACs",
+    db.Column("SAE_code", db.String(5), db.ForeignKey("SAE.code")),
+    db.Column("AC_code", db.String(6), db.ForeignKey("AC.code"))
+)
+
 class PN(db.Model):
     code = db.Column(db.String(3), primary_key = True)
     nom = db.Column(db.String(255))
@@ -13,7 +28,7 @@ class PN(db.Model):
 class AC(db.Model):
     code = db.Column(db.String(6), primary_key = True)
     titre = db.Column(db.String(255))
-    saes = db.Column(db.String(255))
+    saes = db.relationship("SAE", secondary=SAEs_ACs, lazy=True, backref=db.backref("acs", lazy=True))
 
     def __repr__(self):
         return "<AC {}>".format(self.code)
@@ -27,8 +42,8 @@ class SAE(db.Model):
     projet = db.Column(db.String(3))
     description = db.Column(db.Text())
     coef = db.Column(db.String(255))
-    acs = db.Column(db.String(255))
-    ressources = db.Column(db.String(255))
+    #acs = db.relationship("AC", secondary=SAEs_ACs, lazy=True, backref=db.backref("saes", lazy=True))
+    ressources = db.relationship("Ressource", secondary=Ressources_SAEs, lazy=True, backref=db.backref("saes", lazy=True))
     livrables = db.Column(db.Text())
     motscles = db.Column(db.String(255))
 
@@ -42,8 +57,8 @@ class Ressource(db.Model):
     heures_formation = db.Column(db.String(3))
     heures_tp = db.Column(db.String(3))
     coef = db.Column(db.String(255))
-    acs = db.Column(db.String(255))
-    saes = db.Column(db.String(255))
+    #acs = db.relationship("AC", secondary=Ressources_ACs, lazy=True, backref=db.backref("ressources", lazy=True))
+    #saes = db.relationship("SAE", secondary=Ressources_SAEs, lazy=True, backref=db.backref("ressources", lazy=True))
     prerequis = db.Column(db.String(255))
     contexte = db.Column(db.Text())
     contenu = db.Column(db.Text())
diff --git a/migrations/versions/e52d97e91e29_.py b/migrations/versions/e52d97e91e29_.py
new file mode 100644
index 0000000..ec334ee
--- /dev/null
+++ b/migrations/versions/e52d97e91e29_.py
@@ -0,0 +1,57 @@
+"""empty message
+
+Revision ID: e52d97e91e29
+Revises: c000b3a8d714
+Create Date: 2021-05-07 14:03:45.369279
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'e52d97e91e29'
+down_revision = 'c000b3a8d714'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('Ressources_ACs',
+    sa.Column('Ressource_code', sa.String(length=4), nullable=True),
+    sa.Column('AC_code', sa.String(length=6), nullable=True),
+    sa.ForeignKeyConstraint(['AC_code'], ['AC.code'], ),
+    sa.ForeignKeyConstraint(['Ressource_code'], ['ressource.code'], )
+    )
+    op.create_table('Ressources_SAEs',
+    sa.Column('Ressource_code', sa.String(length=4), nullable=True),
+    sa.Column('SAE_code', sa.String(length=5), nullable=True),
+    sa.ForeignKeyConstraint(['Ressource_code'], ['ressource.code'], ),
+    sa.ForeignKeyConstraint(['SAE_code'], ['SAE.code'], )
+    )
+    op.create_table('SAEs_ACs',
+    sa.Column('SAE_code', sa.String(length=5), nullable=True),
+    sa.Column('AC_code', sa.String(length=6), nullable=True),
+    sa.ForeignKeyConstraint(['AC_code'], ['AC.code'], ),
+    sa.ForeignKeyConstraint(['SAE_code'], ['SAE.code'], )
+    )
+    op.drop_column('AC', 'saes')
+    op.drop_column('SAE', 'ressources')
+    op.drop_column('SAE', 'acs')
+    op.drop_column('ressource', 'saes')
+    op.drop_column('ressource', 'acs')
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('ressource', sa.Column('acs', sa.VARCHAR(length=255), nullable=True))
+    op.add_column('ressource', sa.Column('saes', sa.VARCHAR(length=255), nullable=True))
+    op.add_column('SAE', sa.Column('acs', sa.VARCHAR(length=255), nullable=True))
+    op.add_column('SAE', sa.Column('ressources', sa.VARCHAR(length=255), nullable=True))
+    op.add_column('AC', sa.Column('saes', sa.VARCHAR(length=255), nullable=True))
+    op.drop_table('SAEs_ACs')
+    op.drop_table('Ressources_SAEs')
+    op.drop_table('Ressources_ACs')
+    # ### end Alembic commands ###