diff --git a/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Admin.java b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Admin.java
index 69bcd52..78a98b1 100644
--- a/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Admin.java
+++ b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Admin.java
@@ -14,21 +14,13 @@ import jakarta.persistence.Entity;
 @Getter @Setter @NoArgsConstructor
 @Access(AccessType.FIELD)
 
-public class Admin {
-    
-    @Id
-    @GeneratedValue
-    private Integer id;
-    private String name;
-
-    @OneToOne(mappedBy = "admin")
-    private User user;
+public class Admin extends User{
 
     public Admin(String name){
-        this.name = name;
+        super(name);
     }
     @Override
     public String toString() {
-        return "Admin [id=" + id + " , name=" + name + "]";
+        return "Admin [id=" + super.getId() + " , name=" + super.getName() + "]";
     }
 }
\ No newline at end of file
diff --git a/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Athlete.java b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Athlete.java
index fb7d318..eed34bd 100644
--- a/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Athlete.java
+++ b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Athlete.java
@@ -17,12 +17,8 @@ import jakarta.persistence.Entity;
 @Data @NoArgsConstructor
 @Access(AccessType.FIELD)
 
-public class Athlete {
+public class Athlete extends User{
     
-    @Id
-    @GeneratedValue
-    private Integer id;
-    private String name;
     private String categorie;
     private String niveau;
     @ElementCollection
@@ -32,15 +28,12 @@ public class Athlete {
     @ManyToMany(mappedBy = "athletes")
     private List<Session> sessions = new ArrayList<>(); // plusieurs sessions sont possibles
 
-    @OneToOne(mappedBy = "athlete")
-    private User user;
-
     public Athlete(String name){
-        this.name = name;
+        super(name);
     }
 
     public Athlete(String name, String categorie, String niveau, List<String> groupe){
-        this.name = name;
+        super(name);
         this.categorie = categorie;
         this.niveau = niveau;
         this.groupe = groupe;
@@ -48,6 +41,6 @@ public class Athlete {
 
     @Override
     public String toString() {
-        return "Athlete [id=" + id + " , name=" + name + "]";
+        return "Athlete [id=" + super.getId() + " , name=" + super.getName() + "]";
     }
 }
diff --git a/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Coach.java b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Coach.java
index 7a11fb5..49228f3 100644
--- a/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Coach.java
+++ b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Coach.java
@@ -17,24 +17,16 @@ import jakarta.persistence.Entity;
 @Getter @Setter @NoArgsConstructor
 @Access(AccessType.FIELD)
 
-public class Coach {
-    
-    @Id
-    @GeneratedValue
-    private Integer id;
-    private String name;
+public class Coach extends User{
 
     @OneToMany(mappedBy = "coach")
     private List<Session> sessions = new ArrayList<>(); // Un coach peut avoir plusieurs sessions
 
-    @OneToOne(mappedBy = "coach")
-    private User user;
-
     public Coach(String name){
-        this.name = name;
+        super(name);
     }
     @Override
     public String toString() {
-        return "Coach [id=" + id + " , name=" + name + "]";
+        return "Coach [id=" + super.getId() + " , name=" + super.getName() + "]";
     }
 }
\ No newline at end of file
diff --git a/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Session.java b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Session.java
index 51b75d2..ba2a14d 100644
--- a/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Session.java
+++ b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/Session.java
@@ -32,7 +32,7 @@ public class Session {
     private String groupe;
 
     @ManyToOne
-    private Coach coach; // un coach par session
+    private User coach; // un coach par session
 
     @ManyToMany
     private List<Athlete> athletes = new ArrayList<>(); // plusieurs athlètes par session
diff --git a/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/User.java b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/User.java
index 4739278..36614d5 100644
--- a/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/User.java
+++ b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/User.java
@@ -26,8 +26,11 @@ public class User implements Serializable {
 
     @Id
     @GeneratedValue
+    @Column(unique = true, nullable = false) 
     private Integer id;
-    @Column(unique = true, nullable = false) // pas possible d'avoir le même nom
+    @Column(nullable = false, unique = true)
+    private String id_keycloak;
+    
     private String name;
     @Column(nullable = false)
     private String motDePasse;
diff --git a/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/UserRole.java b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/UserRole.java
new file mode 100644
index 0000000..92ebe82
--- /dev/null
+++ b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/UserRole.java
@@ -0,0 +1,25 @@
+package hackathon.FrisbYEE.jpa.metier;
+
+import jakarta.persistence.EmbeddedId;
+import jakarta.persistence.Entity;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.MapsId;
+import jakarta.persistence.Table;
+
+@Entity
+@Table(name = "utilisateur_role")
+public class UserRole {
+
+    @EmbeddedId
+    private UserRoleId id;
+
+    @ManyToOne
+    @MapsId("utilisateurId")
+    private User utilisateur;
+
+    @ManyToOne
+    @MapsId("roleId")
+    private Role role;
+
+    // getters/setters
+}
diff --git a/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/UserRoleId.java b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/UserRoleId.java
new file mode 100644
index 0000000..56530cf
--- /dev/null
+++ b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/UserRoleId.java
@@ -0,0 +1,14 @@
+package hackathon.FrisbYEE.jpa.metier;
+
+import java.io.Serializable;
+
+import jakarta.persistence.Embeddable;
+
+@Embeddable
+public class UserRoleId implements Serializable {
+
+    private Long utilisateurId;
+    private Long roleId;
+
+    // equals() & hashCode() OBLIGATOIRES
+}
diff --git a/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/UtilisateurRoleDetails.java b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/UtilisateurRoleDetails.java
new file mode 100644
index 0000000..743535d
--- /dev/null
+++ b/back_end/src/main/java/hackathon/FrisbYEE/jpa/metier/UtilisateurRoleDetails.java
@@ -0,0 +1,23 @@
+package hackathon.FrisbYEE.jpa.metier;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Inheritance;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.MapsId;
+import jakarta.persistence.OneToOne;
+import jakarta.persistence.Table;
+
+@Entity
+@Inheritance(strategy = jakarta.persistence.InheritanceType.JOINED)
+@Table(name = "utilisateur_role_details")
+public abstract class UtilisateurRoleDetails {
+
+    @Id
+    private Long utilisateurId;
+
+    @OneToOne
+    @MapsId
+    @JoinColumn(name = "utilisateur_id")
+    private User utilisateur;
+}