diff --git a/sql/data.sql b/sql/data.sql
deleted file mode 100644
index 3766846..0000000
--- a/sql/data.sql
+++ /dev/null
@@ -1,4 +0,0 @@
-INSERT INTO Clients (email, first_name, image, last_name, password, role)
-VALUES(
-    'dignissim.tempor.arcu@aol.ca', 'Diana', 'null', 'Harrison', 'password', 'USER'
-      )
\ No newline at end of file
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Controller/ArtisanConnectController.java b/src/main/java/_11/asktpk/artisanconnectbackend/Controller/ArtisanConnectController.java
index e2b2033..49b4aa5 100644
--- a/src/main/java/_11/asktpk/artisanconnectbackend/Controller/ArtisanConnectController.java
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/Controller/ArtisanConnectController.java
@@ -1,29 +1,70 @@
 package _11.asktpk.artisanconnectbackend.Controller;
 
-import _11.asktpk.artisanconnectbackend.Model.Notice;
+import _11.asktpk.artisanconnectbackend.Entities.Notice;
+import _11.asktpk.artisanconnectbackend.Repository.ClientRepository;
 import _11.asktpk.artisanconnectbackend.Service.NoticeService;
+import _11.asktpk.artisanconnectbackend.DTO.NoticeDTO;
+import okhttp3.Response;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
+import java.util.ArrayList;
 import java.util.List;
 
+import static org.springframework.web.servlet.function.ServerResponse.status;
+
 @RequestMapping("/api/v1")
 @RestController
 public class ArtisanConnectController {
     @Autowired
     private NoticeService noticeService;
+    @Autowired
+    private ClientRepository clientRepository;
 
     @GetMapping("/notices/all")
     public List<Notice> getAllNotices() {
         return noticeService.getAllNotices();
     }
 
-    @ResponseStatus(HttpStatus.CREATED)
     @PostMapping("/notices/add")
-    public void addNotice(@RequestBody List<Notice> notices_list) {
-        for (Notice notice : notices_list) {
-            noticeService.addNotice(notice);
+    public ResponseEntity<String> addNotice(@RequestBody NoticeDTO dto) {
+        if (!clientRepository.existsById(dto.getClientId())) {
+            return ResponseEntity
+                    .status(HttpStatus.BAD_REQUEST)
+                    .body("Nie znaleziono klienta o ID: " + dto.getClientId());
         }
+        noticeService.addNotice(noticeService.createFromDTO(dto));
+        return ResponseEntity.status(HttpStatus.CREATED).body("Dodano ogłoszenie.");
+    }
+
+
+    // TODO: zamiast dodawać tutaj pętlą, musi to robić NoticeService, trzeba zaimplementować odpowienią metodę
+    @PostMapping("/notices/bulk_add")
+    public ResponseEntity<String> addNotice(@RequestBody List<NoticeDTO> notices_list) {
+        List<String> errors = new ArrayList<>();
+        boolean isError = false;
+        if (notices_list.isEmpty()) {
+            return ResponseEntity
+                    .status(HttpStatus.BAD_REQUEST)
+                    .body("Lista ogłoszeń jest pusta.");
+        }
+        for (NoticeDTO dto : notices_list) {
+            if (!clientRepository.existsById(dto.getClientId())) {
+                isError = true;
+                errors.add("Nie znaleziono klienta o ID: " + dto.getClientId());
+            }
+        }
+        if(isError) {
+            return ResponseEntity
+                    .status(HttpStatus.BAD_REQUEST)
+                    .body(errors.toString());
+        }
+
+        for(NoticeDTO dto : notices_list) {
+            noticeService.addNotice(noticeService.createFromDTO(dto));
+        }
+        return ResponseEntity.status(HttpStatus.CREATED).body("Dodano ogłoszenia.");
     }
 }
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/dto/NoticeDTO.java b/src/main/java/_11/asktpk/artisanconnectbackend/DTO/NoticeDTO.java
similarity index 84%
rename from src/main/java/_11/asktpk/artisanconnectbackend/dto/NoticeDTO.java
rename to src/main/java/_11/asktpk/artisanconnectbackend/DTO/NoticeDTO.java
index 904fa56..0dd7e1a 100644
--- a/src/main/java/_11/asktpk/artisanconnectbackend/dto/NoticeDTO.java
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/DTO/NoticeDTO.java
@@ -1,9 +1,8 @@
-package _11.asktpk.artisanconnectbackend.dto;
+package _11.asktpk.artisanconnectbackend.DTO;
 
-import _11.asktpk.artisanconnectbackend.Model.AttributesNotice;
-import _11.asktpk.artisanconnectbackend.Model.Client;
-import _11.asktpk.artisanconnectbackend.Model.Orders;
-import _11.asktpk.artisanconnectbackend.Model.Payments;
+import _11.asktpk.artisanconnectbackend.Entities.AttributesNotice;
+import _11.asktpk.artisanconnectbackend.Entities.Orders;
+import _11.asktpk.artisanconnectbackend.Entities.Payments;
 import _11.asktpk.artisanconnectbackend.Utils.Enums;
 
 import java.time.LocalDate;
@@ -11,7 +10,7 @@ import java.util.List;
 
 public class NoticeDTO {
     private String title;
-    private Client client;
+    private Long clientId;
     private String description;
     private Double price;
     private Enums.Category category;
@@ -22,12 +21,12 @@ public class NoticeDTO {
     private List<Orders> orders;
     private List<Payments> payments;
 
-    public NoticeDTO(String title, Client client, String description, Double price,
+    public NoticeDTO(String title, Long clientId, String description, Double price,
                      Enums.Category category, List<String> images, Enums.Status status,
                      LocalDate publishDate, List<AttributesNotice> attributesNotices,
                      List<Orders> orders, List<Payments> payments) {
         this.title = title;
-        this.client = client;
+        this.clientId = clientId;
         this.description = description;
         this.price = price;
         this.category = category;
@@ -47,14 +46,6 @@ public class NoticeDTO {
         this.title = title;
     }
 
-    public Client getClient() {
-        return client;
-    }
-
-    public void setClient(Client client) {
-        this.client = client;
-    }
-
     public String getDescription() {
         return description;
     }
@@ -126,4 +117,12 @@ public class NoticeDTO {
     public void setPayments(List<Payments> payments) {
         this.payments = payments;
     }
+
+    public Long getClientId() {
+        return clientId;
+    }
+
+    public void setClientId(Long clientId) {
+        this.clientId = clientId;
+    }
 }
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Model/AttributeValues.java b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/AttributeValues.java
similarity index 87%
rename from src/main/java/_11/asktpk/artisanconnectbackend/Model/AttributeValues.java
rename to src/main/java/_11/asktpk/artisanconnectbackend/Entities/AttributeValues.java
index 9e12408..609aff2 100644
--- a/src/main/java/_11/asktpk/artisanconnectbackend/Model/AttributeValues.java
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/AttributeValues.java
@@ -1,4 +1,4 @@
-package _11.asktpk.artisanconnectbackend.Model;
+package _11.asktpk.artisanconnectbackend.Entities;
 
 import jakarta.persistence.*;
 
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Model/Attributes.java b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/Attributes.java
similarity index 88%
rename from src/main/java/_11/asktpk/artisanconnectbackend/Model/Attributes.java
rename to src/main/java/_11/asktpk/artisanconnectbackend/Entities/Attributes.java
index 3977de2..d521c2c 100644
--- a/src/main/java/_11/asktpk/artisanconnectbackend/Model/Attributes.java
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/Attributes.java
@@ -1,4 +1,4 @@
-package _11.asktpk.artisanconnectbackend.Model;
+package _11.asktpk.artisanconnectbackend.Entities;
 
 import jakarta.persistence.*;
 import java.util.List;
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Model/AttributesNotice.java b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/AttributesNotice.java
similarity index 88%
rename from src/main/java/_11/asktpk/artisanconnectbackend/Model/AttributesNotice.java
rename to src/main/java/_11/asktpk/artisanconnectbackend/Entities/AttributesNotice.java
index ca81745..290645d 100644
--- a/src/main/java/_11/asktpk/artisanconnectbackend/Model/AttributesNotice.java
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/AttributesNotice.java
@@ -1,4 +1,4 @@
-package _11.asktpk.artisanconnectbackend.Model;
+package _11.asktpk.artisanconnectbackend.Entities;
 
 import jakarta.persistence.*;
 
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Entities/Client.java b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/Client.java
new file mode 100644
index 0000000..a174da5
--- /dev/null
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/Client.java
@@ -0,0 +1,102 @@
+package _11.asktpk.artisanconnectbackend.Entities;
+
+import _11.asktpk.artisanconnectbackend.Utils.Enums.Role;
+
+import jakarta.persistence.*;
+import java.util.List;
+
+@Entity
+@Table(name = "clients")
+public class Client {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    private String email;
+    private String password;
+    private String firstName;
+    private String lastName;
+    private String image; // Optional field
+    @Enumerated(EnumType.STRING)
+    private Role role;
+
+//    @OneToMany(mappedBy = "client", cascade = CascadeType.ALL)
+//    private List<Notice> notices;
+
+    @OneToMany(mappedBy = "client", cascade = CascadeType.ALL)
+    private List<Orders> orders;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long idUser) {
+        this.id = idUser;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public String getImage() {
+        return image;
+    }
+
+    public void setImage(String image) {
+        this.image = image;
+    }
+
+    public Role getRole() {
+        return role;
+    }
+
+    public void setRole(Role role) {
+        this.role = role;
+    }
+
+//    public List<Notice> getNotices() {
+//        return notices;
+//    }
+//
+//    public void setNotices(List<Notice> notices) {
+//        this.notices = notices;
+//    }
+
+    public List<Orders> getOrders() {
+        return orders;
+    }
+
+    public void setOrders(List<Orders> orders) {
+        this.orders = orders;
+    }
+
+    // Getters, setters, and constructors
+}
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Model/GlobalVariables.java b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/GlobalVariables.java
similarity index 84%
rename from src/main/java/_11/asktpk/artisanconnectbackend/Model/GlobalVariables.java
rename to src/main/java/_11/asktpk/artisanconnectbackend/Entities/GlobalVariables.java
index d2e88cf..b1d8676 100644
--- a/src/main/java/_11/asktpk/artisanconnectbackend/Model/GlobalVariables.java
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/GlobalVariables.java
@@ -1,4 +1,4 @@
-package _11.asktpk.artisanconnectbackend.Model;
+package _11.asktpk.artisanconnectbackend.Entities;
 
 import jakarta.persistence.*;
 
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Model/Notice.java b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/Notice.java
similarity index 98%
rename from src/main/java/_11/asktpk/artisanconnectbackend/Model/Notice.java
rename to src/main/java/_11/asktpk/artisanconnectbackend/Entities/Notice.java
index 92cd0d3..d0180bd 100644
--- a/src/main/java/_11/asktpk/artisanconnectbackend/Model/Notice.java
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/Notice.java
@@ -1,4 +1,4 @@
-package _11.asktpk.artisanconnectbackend.Model;
+package _11.asktpk.artisanconnectbackend.Entities;
 
 import jakarta.persistence.*;
 
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Model/Orders.java b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/Orders.java
similarity index 90%
rename from src/main/java/_11/asktpk/artisanconnectbackend/Model/Orders.java
rename to src/main/java/_11/asktpk/artisanconnectbackend/Entities/Orders.java
index 8e8aa2a..9d01112 100644
--- a/src/main/java/_11/asktpk/artisanconnectbackend/Model/Orders.java
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/Orders.java
@@ -1,4 +1,4 @@
-package _11.asktpk.artisanconnectbackend.Model;
+package _11.asktpk.artisanconnectbackend.Entities;
 
 import _11.asktpk.artisanconnectbackend.Utils.Enums.Status;
 
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Model/Payments.java b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/Payments.java
similarity index 91%
rename from src/main/java/_11/asktpk/artisanconnectbackend/Model/Payments.java
rename to src/main/java/_11/asktpk/artisanconnectbackend/Entities/Payments.java
index 4ee6750..9f4cd2e 100644
--- a/src/main/java/_11/asktpk/artisanconnectbackend/Model/Payments.java
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/Entities/Payments.java
@@ -1,4 +1,4 @@
-package _11.asktpk.artisanconnectbackend.Model;
+package _11.asktpk.artisanconnectbackend.Entities;
 
 import _11.asktpk.artisanconnectbackend.Utils.Enums.Status;
 
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Model/Client.java b/src/main/java/_11/asktpk/artisanconnectbackend/Model/Client.java
deleted file mode 100644
index b73990b..0000000
--- a/src/main/java/_11/asktpk/artisanconnectbackend/Model/Client.java
+++ /dev/null
@@ -1,30 +0,0 @@
-package _11.asktpk.artisanconnectbackend.Model;
-
-import _11.asktpk.artisanconnectbackend.Utils.Enums.Role;
-
-import jakarta.persistence.*;
-import java.util.List;
-
-@Entity
-@Table(name = "clients")
-public class Client {
-    @Id
-    @GeneratedValue(strategy = GenerationType.IDENTITY)
-    private Long idUser;
-
-    private String email;
-    private String password;
-    private String firstName;
-    private String lastName;
-    private String image; // Optional field
-    @Enumerated(EnumType.STRING)
-    private Role role;
-
-    @OneToMany(mappedBy = "client", cascade = CascadeType.ALL)
-    private List<Notice> notices;
-
-    @OneToMany(mappedBy = "client", cascade = CascadeType.ALL)
-    private List<Orders> orders;
-
-    // Getters, setters, and constructors
-}
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Repository/ClientRepository.java b/src/main/java/_11/asktpk/artisanconnectbackend/Repository/ClientRepository.java
new file mode 100644
index 0000000..5c7bd16
--- /dev/null
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/Repository/ClientRepository.java
@@ -0,0 +1,7 @@
+package _11.asktpk.artisanconnectbackend.Repository;
+
+import _11.asktpk.artisanconnectbackend.Entities.Client;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface ClientRepository extends JpaRepository<Client, Long> {
+}
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Repository/NoticeRepository.java b/src/main/java/_11/asktpk/artisanconnectbackend/Repository/NoticeRepository.java
index ed19f4f..a2d8626 100644
--- a/src/main/java/_11/asktpk/artisanconnectbackend/Repository/NoticeRepository.java
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/Repository/NoticeRepository.java
@@ -1,6 +1,6 @@
 package _11.asktpk.artisanconnectbackend.Repository;
 
-import _11.asktpk.artisanconnectbackend.Model.Notice;
+import _11.asktpk.artisanconnectbackend.Entities.Notice;
 
 import org.springframework.data.jpa.repository.JpaRepository;
 
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Service/IDatabase.java b/src/main/java/_11/asktpk/artisanconnectbackend/Service/IDatabase.java
index 622d594..962c55c 100644
--- a/src/main/java/_11/asktpk/artisanconnectbackend/Service/IDatabase.java
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/Service/IDatabase.java
@@ -1,6 +1,6 @@
 package _11.asktpk.artisanconnectbackend.Service;
 
-import _11.asktpk.artisanconnectbackend.Model.Notice;
+import _11.asktpk.artisanconnectbackend.Entities.Notice;
 
 import java.util.List;
 
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Service/NoticeService.java b/src/main/java/_11/asktpk/artisanconnectbackend/Service/NoticeService.java
index b698061..768ce8f 100644
--- a/src/main/java/_11/asktpk/artisanconnectbackend/Service/NoticeService.java
+++ b/src/main/java/_11/asktpk/artisanconnectbackend/Service/NoticeService.java
@@ -1,8 +1,11 @@
 package _11.asktpk.artisanconnectbackend.Service;
 
-import _11.asktpk.artisanconnectbackend.Model.Notice;
+import _11.asktpk.artisanconnectbackend.Entities.Client;
+import _11.asktpk.artisanconnectbackend.Entities.Notice;
+import _11.asktpk.artisanconnectbackend.Repository.ClientRepository;
 import _11.asktpk.artisanconnectbackend.Repository.NoticeRepository;
-import _11.asktpk.artisanconnectbackend.dto.NoticeDTO;
+import _11.asktpk.artisanconnectbackend.DTO.NoticeDTO;
+import jakarta.persistence.EntityNotFoundException;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
@@ -14,17 +17,45 @@ public class NoticeService {
     @Autowired
     private NoticeRepository noticeRepository;
 
-//    private NoticeDTO mapToDTO(Notice notice) {
-//        return new NoticeDTO(
-//
-//        );
-//    }
-//
-//    private Notice mapToEntity(NoticeDTO productDTO) {
-//        return new Notice(
-//
-//        );
-//    }
+    @Autowired
+    private ClientRepository clientRepository;
+
+    public Notice createFromDTO(NoticeDTO dto) {
+        Notice notice = new Notice();
+        notice.setTitle(dto.getTitle());
+        notice.setDescription(dto.getDescription());
+        notice.setPrice(dto.getPrice());
+        notice.setCategory(dto.getCategory());
+        notice.setImages(dto.getImages());
+        notice.setStatus(dto.getStatus());
+        notice.setPublishDate(dto.getPublishDate());
+        notice.setAttributesNotices(dto.getAttributesNotices());
+        notice.setOrders(dto.getOrders());
+        notice.setPayments(dto.getPayments());
+
+        Client client = clientRepository.findById(dto.getClientId())
+                .orElseThrow(() -> new EntityNotFoundException("Nie znaleziono klienta o ID: " + dto.getClientId()));
+        notice.setClient(client);
+
+        return notice;
+    }
+
+    // Metoda do konwersji Notice na DTO
+    public NoticeDTO toDTO(Notice notice) {
+        return new NoticeDTO(
+                notice.getTitle(),
+                notice.getClient().getId(),
+                notice.getDescription(),
+                notice.getPrice(),
+                notice.getCategory(),
+                notice.getImages(),
+                notice.getStatus(),
+                notice.getPublishDate(),
+                notice.getAttributesNotices(),
+                notice.getOrders(),
+                notice.getPayments()
+        );
+    }
 
     public List<Notice> getAllNotices() {
         return noticeRepository.findAll();
diff --git a/src/main/java/_11/asktpk/artisanconnectbackend/Service/PostgresDatabase.java b/src/main/java/_11/asktpk/artisanconnectbackend/Service/PostgresDatabase.java
deleted file mode 100644
index d78ce5a..0000000
--- a/src/main/java/_11/asktpk/artisanconnectbackend/Service/PostgresDatabase.java
+++ /dev/null
@@ -1,24 +0,0 @@
-package _11.asktpk.artisanconnectbackend.Service;
-
-import _11.asktpk.artisanconnectbackend.Model.Notice;
-import _11.asktpk.artisanconnectbackend.Repository.NoticeRepository;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.stereotype.Service;
-
-import java.util.List;
-
-@Service
-public class PostgresDatabase implements IDatabase{
-    @Autowired
-    private NoticeRepository noticeRepository;
-
-    @Override
-    public void add(Notice newNotice) {
-        noticeRepository.save(newNotice);
-    }
-
-    @Override
-    public List<Notice> get() {
-        return noticeRepository.findAll();
-    }
-}
diff --git a/src/main/resources/sql/data.sql b/src/main/resources/sql/data.sql
new file mode 100644
index 0000000..eaed99a
--- /dev/null
+++ b/src/main/resources/sql/data.sql
@@ -0,0 +1,2 @@
+INSERT INTO clients (email, first_name, image, last_name, password, role)
+VALUES ('dignissim.tempor.arcu@aol.ca', 'Diana', 'null', 'Harrison', 'password', 'USER');
\ No newline at end of file
diff --git a/src/test/java/_11/asktpk/artisanconnectbackend/ArtisanConnectBackendApplicationTests.java b/src/test/java/_11/asktpk/artisanconnectbackend/ArtisanConnectBackendApplicationTests.java
index b26a99f..227b6a0 100644
--- a/src/test/java/_11/asktpk/artisanconnectbackend/ArtisanConnectBackendApplicationTests.java
+++ b/src/test/java/_11/asktpk/artisanconnectbackend/ArtisanConnectBackendApplicationTests.java
@@ -1,23 +1,13 @@
 package _11.asktpk.artisanconnectbackend;
 
-import _11.asktpk.artisanconnectbackend.Model.Notice;
-import _11.asktpk.artisanconnectbackend.Service.PostgresDatabase;
-import okhttp3.*;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.junit.jupiter.api.Test;
-import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
 
-import java.io.IOException;
-
 @SpringBootTest
 class ArtisanConnectBackendApplicationTests {
     private static final Logger logger = LogManager.getLogger(ArtisanConnectBackendApplicationTests.class);
 
-    @Autowired
-    PostgresDatabase postgresDatabase;
-
 //    @Test
 //    void testPostgresDatabase() {
 //        postgresDatabase.add(new Notice("Test Notice", "Username", "Test Description"));