diff --git a/src/main/java/cat/udl/eps/softarch/tfgfinder/domain/Chat.java b/src/main/java/cat/udl/eps/softarch/tfgfinder/domain/Chat.java
index c40d2a4..a60a978 100644
--- a/src/main/java/cat/udl/eps/softarch/tfgfinder/domain/Chat.java
+++ b/src/main/java/cat/udl/eps/softarch/tfgfinder/domain/Chat.java
@@ -1,11 +1,6 @@
 package cat.udl.eps.softarch.tfgfinder.domain;
 
-import jakarta.persistence.Entity;
-import jakarta.persistence.GeneratedValue;
-import jakarta.persistence.GenerationType;
-import jakarta.persistence.Id;
-import jakarta.persistence.ManyToOne;
-import jakarta.persistence.OneToMany;
+import jakarta.persistence.*;
 import lombok.Data;
 import lombok.EqualsAndHashCode;
 
@@ -19,4 +14,6 @@ public class Chat extends UriEntity<Long>{
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
+    @OneToOne
+    private Proposal proposal;
 }
diff --git a/src/main/java/cat/udl/eps/softarch/tfgfinder/domain/Message.java b/src/main/java/cat/udl/eps/softarch/tfgfinder/domain/Message.java
index fc78089..41b10df 100644
--- a/src/main/java/cat/udl/eps/softarch/tfgfinder/domain/Message.java
+++ b/src/main/java/cat/udl/eps/softarch/tfgfinder/domain/Message.java
@@ -24,6 +24,7 @@ public class Message extends UriEntity<Long> {
     @NotBlank
     private String text;
 
+    @NotNull
     @ManyToOne
     private User from;
 
diff --git a/src/main/java/cat/udl/eps/softarch/tfgfinder/repository/ChatRepository.java b/src/main/java/cat/udl/eps/softarch/tfgfinder/repository/ChatRepository.java
index 8b05d41..cbfc56f 100644
--- a/src/main/java/cat/udl/eps/softarch/tfgfinder/repository/ChatRepository.java
+++ b/src/main/java/cat/udl/eps/softarch/tfgfinder/repository/ChatRepository.java
@@ -1,13 +1,17 @@
 package cat.udl.eps.softarch.tfgfinder.repository;
 
-import cat.udl.eps.softarch.tfgfinder.domain.Message;
+import cat.udl.eps.softarch.tfgfinder.domain.Chat;
 import org.springframework.data.repository.CrudRepository;
 import org.springframework.data.repository.PagingAndSortingRepository;
 import org.springframework.data.rest.core.annotation.RepositoryRestResource;
 
+import java.util.List;
+
+
 @RepositoryRestResource
-public interface ChatRepository extends CrudRepository<Message, Long>, PagingAndSortingRepository<Message, Long> {
+public interface ChatRepository extends CrudRepository<Chat, Long>, PagingAndSortingRepository<Chat, Long> {
 
+    List<Chat> findByProposalId(Long proposal_id);
 
 
 }
diff --git a/src/main/java/cat/udl/eps/softarch/tfgfinder/repository/MessageRepository.java b/src/main/java/cat/udl/eps/softarch/tfgfinder/repository/MessageRepository.java
index a034af4..985bc10 100644
--- a/src/main/java/cat/udl/eps/softarch/tfgfinder/repository/MessageRepository.java
+++ b/src/main/java/cat/udl/eps/softarch/tfgfinder/repository/MessageRepository.java
@@ -13,18 +13,10 @@
 @RepositoryRestResource
 public interface MessageRepository extends CrudRepository<Message, Long>, PagingAndSortingRepository<Message, Long> {
 
-    /* Interface provides automatically, as defined in
-     * https://docs.spring.io/spring-data/commons/docs/current/api/org/springframework/data/repository/CrudRepository.html
-     * and
-     * https://docs.spring.io/spring-data/commons/docs/current/api/org/springframework/data/repository/PagingAndSortingRepository.html
-     * the methods: count, delete, deleteAll, deleteById, existsById, findAll, findAllById, findById, save, saveAll,...
-     *
-     * Additional methods like findByUsernameContaining can be defined following:
-     * https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#jpa.query-methods.query-creation
-     */
-
     List<Message> findByWhen(@Param("when")ZonedDateTime when);
 
     List<Message> findByFrom(@Param("user") User from);
 
+    List<Message> findByChatId(@Param("chatId") Long chatId);
+
 }