diff --git a/pom.xml b/pom.xml
index a41f2fc..0145b6f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -7,7 +7,7 @@
     <version>0.0.2</version>
     <packaging>war</packaging>
 
-    <name>Sale Dock - v${version}</name>
+    <name>Sale Dock - v${project.version}</name>
 
     <properties>
         <maven.compiler.source>17</maven.compiler.source>
@@ -55,6 +55,12 @@
             <artifactId>jersey-hk2</artifactId>
             <version>3.1.5</version>
         </dependency>
+        <dependency>
+            <groupId>commons-codec</groupId>
+            <artifactId>commons-codec</artifactId>
+            <version>1.16.0</version>
+        </dependency>
+
     </dependencies>
     <build>
         <plugins>
diff --git a/src/main/java/io/hardingadonis/saledock/dao/ICategoryDAO.java b/src/main/java/io/hardingadonis/saledock/dao/ICategoryDAO.java
new file mode 100644
index 0000000..7df4f1b
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/dao/ICategoryDAO.java
@@ -0,0 +1,6 @@
+package io.hardingadonis.saledock.dao;
+
+import io.hardingadonis.saledock.model.*;
+
+public interface ICategoryDAO extends IDAO<Category> {
+}
\ No newline at end of file
diff --git a/src/main/java/io/hardingadonis/saledock/dao/ICustomerDAO.java b/src/main/java/io/hardingadonis/saledock/dao/ICustomerDAO.java
new file mode 100644
index 0000000..3152daa
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/dao/ICustomerDAO.java
@@ -0,0 +1,6 @@
+package io.hardingadonis.saledock.dao;
+
+import io.hardingadonis.saledock.model.*;
+
+public interface ICustomerDAO extends IDAO<Customer> {
+}
\ No newline at end of file
diff --git a/src/main/java/io/hardingadonis/saledock/dao/IDAO.java b/src/main/java/io/hardingadonis/saledock/dao/IDAO.java
new file mode 100644
index 0000000..e111955
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/dao/IDAO.java
@@ -0,0 +1,14 @@
+package io.hardingadonis.saledock.dao;
+
+import java.util.*;
+
+public interface IDAO<T> {
+
+    public void add(T obj);
+    
+    public Optional<T> getByID(Integer ID);
+    
+    public List<T> getAll();
+    
+    void update(T obj);
+}
diff --git a/src/main/java/io/hardingadonis/saledock/dao/IEmployeeDAO.java b/src/main/java/io/hardingadonis/saledock/dao/IEmployeeDAO.java
new file mode 100644
index 0000000..004a7e2
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/dao/IEmployeeDAO.java
@@ -0,0 +1,6 @@
+package io.hardingadonis.saledock.dao;
+
+import io.hardingadonis.saledock.model.*;
+
+public interface IEmployeeDAO extends IDAO<Employee> {
+}
\ No newline at end of file
diff --git a/src/main/java/io/hardingadonis/saledock/dao/IOrderDAO.java b/src/main/java/io/hardingadonis/saledock/dao/IOrderDAO.java
new file mode 100644
index 0000000..6805134
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/dao/IOrderDAO.java
@@ -0,0 +1,7 @@
+package io.hardingadonis.saledock.dao;
+
+import io.hardingadonis.saledock.model.*;
+
+public interface IOrderDAO extends IDAO<Order> {
+    
+}
\ No newline at end of file
diff --git a/src/main/java/io/hardingadonis/saledock/dao/IProductDAO.java b/src/main/java/io/hardingadonis/saledock/dao/IProductDAO.java
new file mode 100644
index 0000000..a9bee51
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/dao/IProductDAO.java
@@ -0,0 +1,6 @@
+package io.hardingadonis.saledock.dao;
+
+import io.hardingadonis.saledock.model.*;
+
+public interface IProductDAO extends IDAO<Product> {
+}
\ No newline at end of file
diff --git a/src/main/java/io/hardingadonis/saledock/dao/impl/CategoryDAOImpl.java b/src/main/java/io/hardingadonis/saledock/dao/impl/CategoryDAOImpl.java
new file mode 100644
index 0000000..f66fdd9
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/dao/impl/CategoryDAOImpl.java
@@ -0,0 +1,48 @@
+package io.hardingadonis.saledock.dao.impl;
+
+import io.hardingadonis.saledock.dao.*;
+import io.hardingadonis.saledock.model.*;
+import io.hardingadonis.saledock.utils.*;
+import java.util.*;
+import org.hibernate.*;
+
+public class CategoryDAOImpl implements ICategoryDAO {
+
+    private final SessionFactory sessionFactory;
+
+    public CategoryDAOImpl() {
+        this.sessionFactory = HibernateUtil.getSessionFactory();
+    }
+
+    @Override
+    public void add(Category obj) {
+        try (Session session = sessionFactory.openSession()) {
+            session.beginTransaction();
+            session.persist(obj);
+            session.getTransaction().commit();
+        }
+    }
+
+    @Override
+    public Optional<Category> getByID(Integer ID) {
+        try (Session session = sessionFactory.openSession()) {
+            return Optional.ofNullable(session.get(Category.class, ID));
+        }
+    }
+
+    @Override
+    public List<Category> getAll() {
+        try (Session session = sessionFactory.openSession()) {
+            return session.createQuery("FROM Category", Category.class).getResultList();
+        }
+    }
+
+    @Override
+    public void update(Category obj) {
+        try (Session session = sessionFactory.openSession()) {
+            session.beginTransaction();
+            session.merge(obj);
+            session.getTransaction().commit();
+        }
+    }
+}
diff --git a/src/main/java/io/hardingadonis/saledock/dao/impl/CustomerDAOImpl.java b/src/main/java/io/hardingadonis/saledock/dao/impl/CustomerDAOImpl.java
new file mode 100644
index 0000000..ba08b69
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/dao/impl/CustomerDAOImpl.java
@@ -0,0 +1,48 @@
+package io.hardingadonis.saledock.dao.impl;
+
+import io.hardingadonis.saledock.dao.*;
+import io.hardingadonis.saledock.model.*;
+import io.hardingadonis.saledock.utils.*;
+import java.util.*;
+import org.hibernate.*;
+
+public class CustomerDAOImpl implements ICustomerDAO {
+
+    private final SessionFactory sessionFactory;
+
+    public CustomerDAOImpl() {
+        this.sessionFactory = HibernateUtil.getSessionFactory();
+    }
+
+    @Override
+    public void add(Customer obj) {
+        try (Session session = sessionFactory.openSession()) {
+            session.beginTransaction();
+            session.persist(obj);
+            session.getTransaction().commit();
+        }
+    }
+
+    @Override
+    public Optional<Customer> getByID(Integer ID) {
+        try (Session session = sessionFactory.openSession()) {
+            return Optional.ofNullable(session.get(Customer.class, ID));
+        }
+    }
+
+    @Override
+    public List<Customer> getAll() {
+        try (Session session = sessionFactory.openSession()) {
+            return session.createQuery("FROM Customer", Customer.class).getResultList();
+        }
+    }
+
+    @Override
+    public void update(Customer obj) {
+        try (Session session = sessionFactory.openSession()) {
+            session.beginTransaction();
+            session.merge(obj);
+            session.getTransaction().commit();
+        }
+    }
+}
diff --git a/src/main/java/io/hardingadonis/saledock/dao/impl/EmployeeDAOImpl.java b/src/main/java/io/hardingadonis/saledock/dao/impl/EmployeeDAOImpl.java
new file mode 100644
index 0000000..8694800
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/dao/impl/EmployeeDAOImpl.java
@@ -0,0 +1,48 @@
+package io.hardingadonis.saledock.dao.impl;
+
+import io.hardingadonis.saledock.dao.*;
+import io.hardingadonis.saledock.model.*;
+import io.hardingadonis.saledock.utils.*;
+import java.util.*;
+import org.hibernate.*;
+
+public class EmployeeDAOImpl implements IEmployeeDAO {
+
+    private final SessionFactory sessionFactory;
+
+    public EmployeeDAOImpl() {
+        this.sessionFactory = HibernateUtil.getSessionFactory();
+    }
+
+    @Override
+    public void add(Employee obj) {
+        try (Session session = sessionFactory.openSession()) {
+            session.beginTransaction();
+            session.persist(obj);
+            session.getTransaction().commit();
+        }
+    }
+
+    @Override
+    public Optional<Employee> getByID(Integer ID) {
+        try (Session session = sessionFactory.openSession()) {
+            return Optional.ofNullable(session.get(Employee.class, ID));
+        }
+    }
+
+    @Override
+    public List<Employee> getAll() {
+        try (Session session = sessionFactory.openSession()) {
+            return session.createQuery("FROM Employee", Employee.class).getResultList();
+        }
+    }
+
+    @Override
+    public void update(Employee obj) {
+        try (Session session = sessionFactory.openSession()) {
+            session.beginTransaction();
+            session.merge(obj);
+            session.getTransaction().commit();
+        }
+    }
+}
diff --git a/src/main/java/io/hardingadonis/saledock/dao/impl/OrderDAOImpl.java b/src/main/java/io/hardingadonis/saledock/dao/impl/OrderDAOImpl.java
new file mode 100644
index 0000000..a64b788
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/dao/impl/OrderDAOImpl.java
@@ -0,0 +1,48 @@
+package io.hardingadonis.saledock.dao.impl;
+
+import io.hardingadonis.saledock.dao.*;
+import io.hardingadonis.saledock.model.*;
+import io.hardingadonis.saledock.utils.*;
+import java.util.*;
+import org.hibernate.*;
+
+public class OrderDAOImpl implements IOrderDAO {
+
+    private final SessionFactory sessionFactory;
+
+    public OrderDAOImpl() {
+        this.sessionFactory = HibernateUtil.getSessionFactory();
+    }
+
+    @Override
+    public void add(Order obj) {
+        try (Session session = sessionFactory.openSession()) {
+            session.beginTransaction();
+            session.persist(obj);
+            session.getTransaction().commit();
+        }
+    }
+
+    @Override
+    public Optional<Order> getByID(Integer ID) {
+        try (Session session = sessionFactory.openSession()) {
+            return Optional.ofNullable(session.get(Order.class, ID));
+        }
+    }
+
+    @Override
+    public List<Order> getAll() {
+        try (Session session = sessionFactory.openSession()) {
+            return session.createQuery("FROM Order", Order.class).getResultList();
+        }
+    }
+
+    @Override
+    public void update(Order obj) {
+        try (Session session = sessionFactory.openSession()) {
+            session.beginTransaction();
+            session.merge(obj);
+            session.getTransaction().commit();
+        }
+    }
+}
diff --git a/src/main/java/io/hardingadonis/saledock/dao/impl/ProductDAOImpl.java b/src/main/java/io/hardingadonis/saledock/dao/impl/ProductDAOImpl.java
new file mode 100644
index 0000000..05b193d
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/dao/impl/ProductDAOImpl.java
@@ -0,0 +1,48 @@
+package io.hardingadonis.saledock.dao.impl;
+
+import io.hardingadonis.saledock.dao.*;
+import io.hardingadonis.saledock.model.*;
+import io.hardingadonis.saledock.utils.*;
+import java.util.*;
+import org.hibernate.*;
+
+public class ProductDAOImpl implements IProductDAO {
+
+    private final SessionFactory sessionFactory;
+
+    public ProductDAOImpl() {
+        this.sessionFactory = HibernateUtil.getSessionFactory();
+    }
+
+    @Override
+    public void add(Product obj) {
+        try (Session session = sessionFactory.openSession()) {
+            session.beginTransaction();
+            session.persist(obj);
+            session.getTransaction().commit();
+        }
+    }
+
+    @Override
+    public Optional<Product> getByID(Integer ID) {
+        try (Session session = sessionFactory.openSession()) {
+            return Optional.ofNullable(session.get(Product.class, ID));
+        }
+    }
+
+    @Override
+    public List<Product> getAll() {
+        try (Session session = sessionFactory.openSession()) {
+            return session.createQuery("FROM Product", Product.class).getResultList();
+        }
+    }
+
+    @Override
+    public void update(Product obj) {
+        try (Session session = sessionFactory.openSession()) {
+            session.beginTransaction();
+            session.merge(obj);
+            session.getTransaction().commit();
+        }
+    }
+}
diff --git a/src/main/java/io/hardingadonis/saledock/model/Category.java b/src/main/java/io/hardingadonis/saledock/model/Category.java
new file mode 100644
index 0000000..d39f2ca
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/model/Category.java
@@ -0,0 +1,32 @@
+package io.hardingadonis.saledock.model;
+
+import jakarta.persistence.*;
+import java.time.*;
+import lombok.*;
+
+@Entity(name = "Category")
+@Table(name = "`category`")
+@AllArgsConstructor
+@NoArgsConstructor
+@Getter
+@Setter
+@EqualsAndHashCode
+@ToString
+public class Category {
+
+    @Id
+    @Column(name = "`id`")
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Integer ID;
+
+    @Column(name = "`name`")
+    private String name;
+    
+    @Column(name = "`created_at`")
+    private LocalDateTime createdAt;
+    
+    @PrePersist
+    protected void onCreate() {
+        this.createdAt = LocalDateTime.now(ZoneId.of("Asia/Ho_Chi_Minh"));
+    }
+}
diff --git a/src/main/java/io/hardingadonis/saledock/model/Customer.java b/src/main/java/io/hardingadonis/saledock/model/Customer.java
new file mode 100644
index 0000000..779cd21
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/model/Customer.java
@@ -0,0 +1,49 @@
+package io.hardingadonis.saledock.model;
+
+import jakarta.persistence.*;
+import java.time.*;
+import lombok.*;
+
+@Entity(name = "Customer")
+@Table(name = "`customer`")
+@AllArgsConstructor
+@NoArgsConstructor
+@Getter
+@Setter
+@EqualsAndHashCode
+@ToString
+public class Customer {
+    
+    @Id
+    @Column(name = "`id`")
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Integer ID;
+    
+    @Column(name = "`code`", unique = true)
+    private String code;
+    
+    @Column(name = "`name`")
+    private String name;
+    
+    @Column(name = "`email`", unique = true)
+    private String email;
+    
+    @Column(name = "`address`")
+    private String address;
+    
+    @Column(name = "`created_at`")
+    private LocalDateTime createdAt;
+    
+    @Column(name = "`updated_at`")
+    private LocalDateTime updatedAt;
+    
+    @PrePersist
+    protected void onCreate() {
+        this.createdAt = LocalDateTime.now(ZoneId.of("Asia/Ho_Chi_Minh"));
+    }
+    
+    @PreUpdate
+    protected void onUpdate() {
+        this.updatedAt = LocalDateTime.now(ZoneId.of("Asia/Ho_Chi_Minh"));
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/io/hardingadonis/saledock/model/Employee.java b/src/main/java/io/hardingadonis/saledock/model/Employee.java
new file mode 100644
index 0000000..dbdd99a
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/model/Employee.java
@@ -0,0 +1,46 @@
+package io.hardingadonis.saledock.model;
+
+import jakarta.persistence.*;
+import java.time.*;
+import lombok.*;
+
+@Entity(name = "Employee")
+@Table(name = "`employee`")
+@AllArgsConstructor
+@NoArgsConstructor
+@Getter
+@Setter
+@EqualsAndHashCode
+@ToString
+public class Employee {
+
+    @Id
+    @Column(name = "`id`")
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Integer ID;
+
+    @Column(name = "`code`", unique = true)
+    private String code;
+    
+    @Column(name = "`password`", nullable = false)
+    private String hashedPassword;
+    
+    @Column(name = "`name`", nullable = false)
+    private String fullName;
+    
+    @Column(name = "`created_at`")
+    private LocalDateTime createdAt;
+    
+    @Column(name = "`updated_at`")
+    private LocalDateTime updatedAt;
+    
+    @PrePersist
+    protected void onCreate() {
+        this.createdAt = LocalDateTime.now(ZoneId.of("Asia/Ho_Chi_Minh"));
+    }
+    
+    @PreUpdate
+    protected void onUpdate() {
+        this.updatedAt = LocalDateTime.now(ZoneId.of("Asia/Ho_Chi_Minh"));
+    }
+}
diff --git a/src/main/java/io/hardingadonis/saledock/model/Model.java b/src/main/java/io/hardingadonis/saledock/model/Model.java
deleted file mode 100644
index abec6d3..0000000
--- a/src/main/java/io/hardingadonis/saledock/model/Model.java
+++ /dev/null
@@ -1,3 +0,0 @@
-package io.hardingadonis.saledock.model;
-
-public class Model {}
diff --git a/src/main/java/io/hardingadonis/saledock/model/Order.java b/src/main/java/io/hardingadonis/saledock/model/Order.java
new file mode 100644
index 0000000..a6992e2
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/model/Order.java
@@ -0,0 +1,76 @@
+package io.hardingadonis.saledock.model;
+
+import jakarta.persistence.*;
+import java.time.*;
+import java.util.*;
+import lombok.*;
+
+@Entity(name = "Order")
+@Table(name = "`order`")
+@AllArgsConstructor
+@NoArgsConstructor
+@Getter
+@Setter
+@EqualsAndHashCode
+@ToString
+public class Order {
+
+    public static enum Status {
+        PENDING,
+        SHIPPING,
+        DONE,
+        CANCELLED
+    }
+
+    @Id
+    @Column(name = "`id`")
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Integer ID;
+
+    @Column(name = "`code`", unique = true)
+    private String code;
+
+    @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
+    @JoinColumn(name = "`employee_id`", nullable = false)
+    private Employee employee;
+
+    @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
+    @JoinColumn(name = "`customer_id`", nullable = false)
+    private Customer customer;
+
+    @Enumerated(EnumType.STRING)
+    @Column(name = "`status`", nullable = false)
+    private Status status;
+
+    @Column(name = "`total`", nullable = false)
+    private Double total;
+
+    @Column(name = "`note`", columnDefinition = "longtext")
+    private String note;
+
+    @Column(name = "`created_at`")
+    private LocalDateTime createdAt;
+
+    @Column(name = "`updated_at`")
+    private LocalDateTime updatedAt;
+
+    @OneToMany(mappedBy = "order", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
+    private List<OrderDetail> orderDetails = new ArrayList<>();
+
+    @PrePersist
+    protected void onCreate() {
+        this.createdAt = LocalDateTime.now(ZoneId.of("Asia/Ho_Chi_Minh"));
+    }
+
+    @PreUpdate
+    protected void onUpdate() {
+        this.updatedAt = LocalDateTime.now(ZoneId.of("Asia/Ho_Chi_Minh"));
+    }
+
+    public void addProduct(Product product, Integer quantity) {
+        var detail = new OrderDetail(this, product);
+        detail.setQuantity(quantity);
+
+        this.orderDetails.add(detail);
+    }
+}
diff --git a/src/main/java/io/hardingadonis/saledock/model/OrderDetail.java b/src/main/java/io/hardingadonis/saledock/model/OrderDetail.java
new file mode 100644
index 0000000..c11c8a4
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/model/OrderDetail.java
@@ -0,0 +1,52 @@
+package io.hardingadonis.saledock.model;
+
+import jakarta.persistence.*;
+import java.io.*;
+import lombok.*;
+
+@Entity(name = "OrderDetail")
+@Table(name = "order_detail")
+@AllArgsConstructor
+@NoArgsConstructor
+@Getter
+@Setter
+@EqualsAndHashCode
+@ToString(exclude = {"order"})
+public class OrderDetail {
+
+    @Embeddable
+    @AllArgsConstructor
+    @NoArgsConstructor
+    @Getter
+    @Setter
+    @EqualsAndHashCode
+    @ToString
+    public static class ID implements Serializable {
+
+        @Column(name = "`order_id`")
+        private Integer orderID;
+
+        @Column(name = "`product_id`")
+        private Integer productID;
+    }
+
+    @EmbeddedId
+    private ID ID;
+    
+    @ManyToOne(fetch = FetchType.LAZY)
+    @MapsId("orderID")
+    private Order order;
+    
+    @ManyToOne(fetch = FetchType.LAZY)
+    @MapsId("productID")
+    private Product product;
+
+    @Column(name = "`quantity`", nullable = false)
+    private int quantity;
+    
+    public OrderDetail(Order order, Product product) {
+        this.order = order;
+        this.product = product;
+        this.ID = new ID(order.getID(), product.getID());
+    }
+}
diff --git a/src/main/java/io/hardingadonis/saledock/model/Product.java b/src/main/java/io/hardingadonis/saledock/model/Product.java
new file mode 100644
index 0000000..0fa397b
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/model/Product.java
@@ -0,0 +1,64 @@
+package io.hardingadonis.saledock.model;
+
+import jakarta.persistence.*;
+import java.time.*;
+import lombok.*;
+
+@Entity(name = "Product")
+@Table(name = "`product`")
+@AllArgsConstructor
+@NoArgsConstructor
+@Getter
+@Setter
+@EqualsAndHashCode
+@ToString
+public class Product {
+
+    @Id
+    @Column(name = "`id`")
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Integer ID;
+
+    @Column(name = "`code`", unique = true)
+    private String code;
+
+    @Column(name = "`name`", nullable = false)
+    private String name;
+
+    @Column(name = "`description`", columnDefinition = "longtext")
+    private String description;
+
+    @Column(name = "`price`", nullable = false)
+    private Double price;
+
+    @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
+    @JoinColumn(name = "`category_id`", nullable = false)
+    private Category category;
+
+    @Column(name = "`image_url`", columnDefinition = "longtext")
+    private String imageURLs;
+
+    @Column(name = "`created_at`")
+    private LocalDateTime createdAt;
+
+    @Column(name = "`updated_at`")
+    private LocalDateTime updatedAt;
+
+    @PrePersist
+    protected void onCreate() {
+        this.createdAt = LocalDateTime.now(ZoneId.of("Asia/Ho_Chi_Minh"));
+
+        if (this.imageURLs == null || this.imageURLs.isBlank()) {
+            this.imageURLs = "[]";
+        }
+    }
+
+    @PreUpdate
+    protected void onUpdate() {
+        this.updatedAt = LocalDateTime.now(ZoneId.of("Asia/Ho_Chi_Minh"));
+
+        if (this.imageURLs == null || this.imageURLs.isBlank()) {
+            this.imageURLs = "[]";
+        }
+    }
+}
diff --git a/src/main/java/io/hardingadonis/saledock/utils/Hash.java b/src/main/java/io/hardingadonis/saledock/utils/Hash.java
new file mode 100644
index 0000000..41101ed
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/utils/Hash.java
@@ -0,0 +1,10 @@
+package io.hardingadonis.saledock.utils;
+
+import org.apache.commons.codec.digest.*;
+
+public class Hash {
+
+    public static String MD5(String message) {
+        return DigestUtils.md5Hex(message);
+    }
+}
diff --git a/src/main/java/io/hardingadonis/saledock/utils/Singleton.java b/src/main/java/io/hardingadonis/saledock/utils/Singleton.java
new file mode 100644
index 0000000..87931cb
--- /dev/null
+++ b/src/main/java/io/hardingadonis/saledock/utils/Singleton.java
@@ -0,0 +1,29 @@
+package io.hardingadonis.saledock.utils;
+
+import io.hardingadonis.saledock.dao.*;
+import io.hardingadonis.saledock.dao.impl.*;
+
+public class Singleton {
+
+    public static ICategoryDAO categoryDAO;
+
+    public static ICustomerDAO customerDAO;
+
+    public static IEmployeeDAO employeeDAO;
+
+    public static IOrderDAO orderDAO;
+
+    public static IProductDAO productDAO;
+
+    static {
+        categoryDAO = new CategoryDAOImpl();
+        
+        customerDAO = new CustomerDAOImpl();
+        
+        employeeDAO = new EmployeeDAOImpl();
+        
+        orderDAO = new OrderDAOImpl();
+        
+        productDAO = new ProductDAOImpl();
+    }
+}
diff --git a/src/main/resources/hibernate.cfg.xml b/src/main/resources/hibernate.cfg.xml
index a06d8ce..1f441f1 100644
--- a/src/main/resources/hibernate.cfg.xml
+++ b/src/main/resources/hibernate.cfg.xml
@@ -9,16 +9,25 @@
         <property name="hibernate.connection.password"></property>
         
         <!-- Specify dialect -->
-        <property name="hibernate.dialect">org.hibernate.dialect.MySQL8Dialect</property>
+        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
         
         <!-- Echo all executed SQL to stdout -->
         <property name="hibernate.show_sql">true</property>
+        <property name="hibernate.format_sql">true</property>
+        <property name="hibernate.highlight_sql">true</property>
         
         <!-- Drop and re-create the database schema on startup -->
         <property name="hibernate.hbm2ddl.auto">update</property>
         
+        <property name="hibernate.enable_lazy_load_no_trans">true</property>
+        
         <!-- Mention annotated class -->
-        <!--<mapping class="com.example.YourEntityClass"/>-->
+        <mapping class="io.hardingadonis.saledock.model.Category"/>
+        <mapping class="io.hardingadonis.saledock.model.Customer"/>
+        <mapping class="io.hardingadonis.saledock.model.Employee"/>
+        <mapping class="io.hardingadonis.saledock.model.Order"/>
+        <mapping class="io.hardingadonis.saledock.model.OrderDetail"/>
+        <mapping class="io.hardingadonis.saledock.model.Product"/>
         
     </session-factory>
 </hibernate-configuration>
\ No newline at end of file