diff --git a/API_SQLuedo/DbContextLib/UserDbContext.cs b/API_SQLuedo/DbContextLib/UserDbContext.cs
index 8be1c6f..6352ab8 100644
--- a/API_SQLuedo/DbContextLib/UserDbContext.cs
+++ b/API_SQLuedo/DbContextLib/UserDbContext.cs
@@ -30,7 +30,6 @@ namespace DbContextLib
         protected override void OnModelCreating(ModelBuilder modelBuilder)
         {
             modelBuilder.Entity<ContentLessonEntity>().HasKey(c => c.LessonId);
-            modelBuilder.Entity<ContentLessonEntity>().HasKey(c => c.LessonPartId);
             modelBuilder.Entity<SuccessEntity>().HasKey(s => s.UserId);
             modelBuilder.Entity<SuccessEntity>().HasKey(s => s.InquiryId);
             modelBuilder.Entity<InquiryEntity>().HasKey(s => s.Id);
diff --git a/API_SQLuedo/Dto/BlackListDTO.cs b/API_SQLuedo/Dto/BlackListDTO.cs
index e614e70..913aaa0 100644
--- a/API_SQLuedo/Dto/BlackListDTO.cs
+++ b/API_SQLuedo/Dto/BlackListDTO.cs
@@ -1,14 +1,13 @@
-namespace Dto
+namespace Dto;
+
+public class BlackListDTO
 {
-    public class BlackListDTO
-    {
-        public string Email { get; set; }
-        public DateOnly ExpirationDate { get; set; }
+    public string Email { get; set; }
+    public DateOnly ExpirationDate { get; set; }
 
-        public BlackListDTO(string email, DateOnly expirationDate)
-        {
-            Email = email;
-            ExpirationDate = expirationDate;
-        }
+    public BlackListDTO(string email, DateOnly expirationDate)
+    {
+        Email = email;
+        ExpirationDate = expirationDate;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Dto/ContentLessonDTO.cs b/API_SQLuedo/Dto/ContentLessonDTO.cs
index ef844e7..778e428 100644
--- a/API_SQLuedo/Dto/ContentLessonDTO.cs
+++ b/API_SQLuedo/Dto/ContentLessonDTO.cs
@@ -1,14 +1,17 @@
-namespace Dto
+namespace Dto;
+
+public abstract class ContentLessonDTO
 {
-    public class ContentLessonDTO
-    {
-        public int LessonId { get; set; }
-        public int LessonPartId { get; set; }
+    public int Id { get; set; }
+    public string ContentContent { get; set; }
+    public string ContentTitle { get; set; }
+    public int LessonId { get; set; }
 
-        public ContentLessonDTO(int lessonId, int lessonPartId)
-        {
-            LessonId = lessonId;
-            LessonPartId = lessonPartId;
-        }
+    protected ContentLessonDTO(int id, string contentContent, string contentTitle, int lessonId)
+    {
+        Id = id;
+        ContentContent = contentContent;
+        ContentTitle = contentTitle;
+        LessonId = lessonId;
     }
 }
\ No newline at end of file
diff --git a/API_SQLuedo/Dto/InquiryDTO.cs b/API_SQLuedo/Dto/InquiryDTO.cs
index a1e438f..5b2ad10 100644
--- a/API_SQLuedo/Dto/InquiryDTO.cs
+++ b/API_SQLuedo/Dto/InquiryDTO.cs
@@ -1,26 +1,25 @@
-namespace Dto
+namespace Dto;
+
+public class InquiryDTO
 {
-    public class InquiryDTO
-    {
-        public int Id { get;}
+    public int Id { get;}
 
-        public string Title { get; set; }
+    public string Title { get; set; }
 
-        public string Description { get; set; }
+    public string Description { get; set; }
 
-        public bool IsUser { get; set; }
+    public bool IsUser { get; set; }
 
-        public int Database { get; set; }
-        public int InquiryTable { get; set; }
+    public int Database { get; set; }
+    public int InquiryTable { get; set; }
 
-        public InquiryDTO(int id, string title, string description, bool isUser, int database, int inquiryTable)
-        {
-            Id = id;
-            Title = title;
-            Description = description;
-            IsUser = isUser;
-            Database = database;
-            InquiryTable = inquiryTable;
-        }
+    public InquiryDTO(int id, string title, string description, bool isUser, int database, int inquiryTable)
+    {
+        Id = id;
+        Title = title;
+        Description = description;
+        IsUser = isUser;
+        Database = database;
+        InquiryTable = inquiryTable;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Dto/InquiryTableDTO.cs b/API_SQLuedo/Dto/InquiryTableDTO.cs
index ce28216..a636053 100644
--- a/API_SQLuedo/Dto/InquiryTableDTO.cs
+++ b/API_SQLuedo/Dto/InquiryTableDTO.cs
@@ -1,19 +1,18 @@
-namespace Dto
+namespace Dto;
+
+public class InquiryTableDTO
 {
-    public class InquiryTableDTO
-    {
 
-        public int OwnerId { get; set; }
-        public string DatabaseName { get; set; }
-        public string ConnectionInfo { get; set; }
+    public int OwnerId { get; set; }
+    public string DatabaseName { get; set; }
+    public string ConnectionInfo { get; set; }
 
-        public InquiryTableDTO() { }
+    public InquiryTableDTO() { }
 
-        public InquiryTableDTO(int ownerId, string databaseName, string connectionInfo)
-        {
-            OwnerId = ownerId;
-            DatabaseName = databaseName;
-            ConnectionInfo = connectionInfo;
-        }
+    public InquiryTableDTO(int ownerId, string databaseName, string connectionInfo)
+    {
+        OwnerId = ownerId;
+        DatabaseName = databaseName;
+        ConnectionInfo = connectionInfo;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Dto/LessonDTO.cs b/API_SQLuedo/Dto/LessonDTO.cs
index 70983ff..8e70b4f 100644
--- a/API_SQLuedo/Dto/LessonDTO.cs
+++ b/API_SQLuedo/Dto/LessonDTO.cs
@@ -1,26 +1,26 @@
-namespace Dto
+namespace Dto;
+
+public class LessonDTO
 {
-    public class LessonDTO
-    {
-        public int Id { get; }
-        public string? Title { get; set; }
-        public string? LastPublisher { get; set; }
-        public DateOnly? LastEdit { get; set; }
+    public int Id { get; }
+    public string? Title { get; set; }
+    public string? LastPublisher { get; set; }
+    public DateOnly? LastEdit { get; set; }
+    public ICollection<ContentLessonDTO> Content { get; set; } = new List<ContentLessonDTO>();
 
-        public LessonDTO() { }
-        public LessonDTO(int id, string title, string lastPublisher, DateOnly? lastEdit)
-        {
-            Id = id;
-            Title = title;
-            LastPublisher = lastPublisher;
-            LastEdit = lastEdit;
-        }
+    public LessonDTO() { }
+    public LessonDTO(int id, string title, string lastPublisher, DateOnly? lastEdit)
+    {
+        Id = id;
+        Title = title;
+        LastPublisher = lastPublisher;
+        LastEdit = lastEdit;
+    }
 
-        public LessonDTO(string title, string lastPublisher, DateOnly? lastEdit)
-        {
-            Title = title;
-            LastPublisher = lastPublisher;
-            LastEdit = lastEdit;
-        }
+    public LessonDTO(string title, string lastPublisher, DateOnly? lastEdit)
+    {
+        Title = title;
+        LastPublisher = lastPublisher;
+        LastEdit = lastEdit;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Dto/NotepadDTO.cs b/API_SQLuedo/Dto/NotepadDTO.cs
index 3e86998..c49e155 100644
--- a/API_SQLuedo/Dto/NotepadDTO.cs
+++ b/API_SQLuedo/Dto/NotepadDTO.cs
@@ -1,26 +1,25 @@
-namespace Dto
+namespace Dto;
+
+public class NotepadDTO
 {
-    public class NotepadDTO
-    {
-        public int Id { get; set; }
-        public int UserId { get; set; }
-        public int InquiryId { get; set; }
-        public string Notes { get; set; }
+    public int Id { get; set; }
+    public int UserId { get; set; }
+    public int InquiryId { get; set; }
+    public string Notes { get; set; }
 
-        public NotepadDTO() { }
+    public NotepadDTO() { }
 
-        public NotepadDTO(int id, int userId, int inquiryId, string notes)
-        {
-            Id = id;
-            UserId = userId;
-            InquiryId = inquiryId;
-            Notes = notes;
-        }
-        public NotepadDTO(int userId, int inquiryId, string notes)
-        {
-            UserId = userId;
-            InquiryId = inquiryId;
-            Notes = notes;
-        }
+    public NotepadDTO(int id, int userId, int inquiryId, string notes)
+    {
+        Id = id;
+        UserId = userId;
+        InquiryId = inquiryId;
+        Notes = notes;
+    }
+    public NotepadDTO(int userId, int inquiryId, string notes)
+    {
+        UserId = userId;
+        InquiryId = inquiryId;
+        Notes = notes;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Dto/ParagraphDTO.cs b/API_SQLuedo/Dto/ParagraphDTO.cs
index c203c9c..1bb2016 100644
--- a/API_SQLuedo/Dto/ParagraphDTO.cs
+++ b/API_SQLuedo/Dto/ParagraphDTO.cs
@@ -1,32 +1,17 @@
-namespace Dto
-{
-    public class ParagraphDTO
-    {
-        public int Id { get; }
-        public string Title { get; set; }
-        public string Content { get; set; }
-        public string Info { get; set; }
-        public string Query { get; set; }
-        public string Comment { get; set; }
+namespace Dto;
 
-        public ParagraphDTO() { }
+public class ParagraphDTO : ContentLessonDTO
+{
+    public string Info { get; set; }
+    public string Query { get; set; }
+    public string Comment { get; set; }
 
-        public ParagraphDTO(int id, string title, string content, string info, string query, string comment)
-        {
-            Id = id;
-            Title = title;
-            Content = content;
-            Info = info;
-            Query = query;
-            Comment = comment;
-        }
-        public ParagraphDTO(string title, string content, string info, string query, string comment)
-        {
-            Title = title;
-            Content = content;
-            Info = info;
-            Query = query;
-            Comment = comment;
-        }
+    public ParagraphDTO(int id, string title, string content, string info, string query, string comment, int lessonId) :
+        base(id, content,
+            title, lessonId)
+    {
+        Info = info;
+        Query = query;
+        Comment = comment;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Dto/SolutionDTO.cs b/API_SQLuedo/Dto/SolutionDTO.cs
index a775fd6..b13daf6 100644
--- a/API_SQLuedo/Dto/SolutionDTO.cs
+++ b/API_SQLuedo/Dto/SolutionDTO.cs
@@ -1,30 +1,29 @@
-namespace Dto
+namespace Dto;
+
+public class SolutionDTO
 {
-    public class SolutionDTO
+    public int OwnerId { get; set; }
+    public string MurdererFirstName { get; set; }
+    public string MurdererLastName { get; set; }
+    public string MurderPlace { get; set; }
+    public string MurderWeapon { get; set; }
+    public string Explanation { get; set; }
+    public SolutionDTO() { }
+    public SolutionDTO(int ownerId, string murdererFirstName, string murdererLastName, string murderPlace, string murderWeapon, string explanation)
     {
-        public int OwnerId { get; set; }
-        public string MurdererFirstName { get; set; }
-        public string MurdererLastName { get; set; }
-        public string MurderPlace { get; set; }
-        public string MurderWeapon { get; set; }
-        public string Explanation { get; set; }
-        public SolutionDTO() { }
-        public SolutionDTO(int ownerId, string murdererFirstName, string murdererLastName, string murderPlace, string murderWeapon, string explanation)
-        {
-            OwnerId = ownerId;
-            MurdererFirstName = murdererFirstName;
-            MurdererLastName = murdererLastName;
-            MurderPlace = murderPlace;
-            MurderWeapon = murderWeapon;
-            Explanation = explanation;
-        }
-        public SolutionDTO(string murdererFirstName, string murdererLastName, string murderPlace, string murderWeapon, string explanation)
-        {
-            MurdererFirstName = murdererFirstName;
-            MurdererLastName = murdererLastName;
-            MurderPlace = murderPlace;
-            MurderWeapon = murderWeapon;
-            Explanation = explanation;
-        }
+        OwnerId = ownerId;
+        MurdererFirstName = murdererFirstName;
+        MurdererLastName = murdererLastName;
+        MurderPlace = murderPlace;
+        MurderWeapon = murderWeapon;
+        Explanation = explanation;
     }
-}
+    public SolutionDTO(string murdererFirstName, string murdererLastName, string murderPlace, string murderWeapon, string explanation)
+    {
+        MurdererFirstName = murdererFirstName;
+        MurdererLastName = murdererLastName;
+        MurderPlace = murderPlace;
+        MurderWeapon = murderWeapon;
+        Explanation = explanation;
+    }
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Dto/SuccessDTO.cs b/API_SQLuedo/Dto/SuccessDTO.cs
index ad3fcb3..87c26a3 100644
--- a/API_SQLuedo/Dto/SuccessDTO.cs
+++ b/API_SQLuedo/Dto/SuccessDTO.cs
@@ -1,18 +1,17 @@
-namespace Dto
+namespace Dto;
+
+public class SuccessDTO
 {
-    public class SuccessDTO
-    {
-        public int UserId { get; set; }
-        public int InquiryId { get; set; }
-        public bool IsFinished { get; set; }
+    public int UserId { get; set; }
+    public int InquiryId { get; set; }
+    public bool IsFinished { get; set; }
 
-        public SuccessDTO() { }
+    public SuccessDTO() { }
 
-        public SuccessDTO(int userId, int inquiryId, bool isFinished)
-        {
-            UserId = userId;
-            InquiryId = inquiryId;
-            IsFinished = isFinished;
-        }
+    public SuccessDTO(int userId, int inquiryId, bool isFinished)
+    {
+        UserId = userId;
+        InquiryId = inquiryId;
+        IsFinished = isFinished;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Dto/UserDTO.cs b/API_SQLuedo/Dto/UserDTO.cs
index 9a96905..b2553f5 100644
--- a/API_SQLuedo/Dto/UserDTO.cs
+++ b/API_SQLuedo/Dto/UserDTO.cs
@@ -1,34 +1,33 @@
-namespace Dto
+namespace Dto;
+
+public class UserDTO
 {
-    public class UserDTO
-    {
-        public int Id { get; set; }
-        public string Username { get; set; }
-        public string Password { get; set; }
-        public string Email { get; set; }
-        public bool IsAdmin { get; set; }
+    public int Id { get; set; }
+    public string Username { get; set; }
+    public string Password { get; set; }
+    public string Email { get; set; }
+    public bool IsAdmin { get; set; }
 
-        public UserDTO() { }
-        public UserDTO(int id, string username, string password, string email, bool isAdmin)
-        {
-            Id = id;
-            Username = username;
-            Password = password;
-            Email = email;
-            IsAdmin = isAdmin;
-        }
+    public UserDTO() { }
+    public UserDTO(int id, string username, string password, string email, bool isAdmin)
+    {
+        Id = id;
+        Username = username;
+        Password = password;
+        Email = email;
+        IsAdmin = isAdmin;
+    }
 
-        public UserDTO(string username, string password, string email, bool isAdmin)
-        {
-            Username = username;
-            Password = password;
-            Email = email;
-            IsAdmin = isAdmin;
-        }
+    public UserDTO(string username, string password, string email, bool isAdmin)
+    {
+        Username = username;
+        Password = password;
+        Email = email;
+        IsAdmin = isAdmin;
+    }
 
-        public override string ToString()
-        {
-            return $"{Id}\t{Username}\t{Email}\t{IsAdmin}";
-        }
+    public override string ToString()
+    {
+        return $"{Id}\t{Username}\t{Email}\t{IsAdmin}";
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/EntityFramework/ContentLessonEntity.cs b/API_SQLuedo/EntityFramework/ContentLessonEntity.cs
index 067cc39..ee81947 100644
--- a/API_SQLuedo/EntityFramework/ContentLessonEntity.cs
+++ b/API_SQLuedo/EntityFramework/ContentLessonEntity.cs
@@ -3,22 +3,37 @@
 namespace Entities;
 
 [Table("ContentLesson")]
-public class ContentLessonEntity
+public abstract class ContentLessonEntity
 {
-    [ForeignKey(nameof(Lesson))]
-    public int LessonId { get; set; }
-    public LessonEntity Lesson { get; set; }
+    public int Id { get; set; }
+    public string ContentContent { get; set; }
+    public string ContentTitle { get; set; }
+    [ForeignKey(nameof(Lesson))] public int LessonId { get; set; }
+    public LessonEntity Lesson { get; set; } = null!;
 
-    [ForeignKey(nameof(Paragraph))]
-    public int LessonPartId { get; set; }
-    public ParagraphEntity Paragraph { get; set; }
+    protected ContentLessonEntity()
+    {
+    }
 
-    public ContentLessonEntity(){}
-    public ContentLessonEntity(int lessonId, LessonEntity lesson, int lessonPartId, ParagraphEntity paragraph)
+    protected ContentLessonEntity(int id, string contentContent, string contentTitle)
     {
+        Id = id;
+        ContentContent = contentContent;
+        ContentTitle = contentTitle;
+    }
+
+
+    protected ContentLessonEntity(int id, int lessonId, string contentContent, string contentTitle)
+    {
+        Id = id;
         LessonId = lessonId;
-        Lesson = lesson;
-        LessonPartId = lessonPartId;
-        Paragraph = paragraph;
+        ContentContent = contentContent;
+        ContentTitle = contentTitle;
+    }
+
+    protected ContentLessonEntity(string contentContent, string contentTitle)
+    {
+        ContentContent = contentContent;
+        ContentTitle = contentTitle;
     }
 }
\ No newline at end of file
diff --git a/API_SQLuedo/EntityFramework/LessonEntity.cs b/API_SQLuedo/EntityFramework/LessonEntity.cs
index 2c345d3..b06f611 100644
--- a/API_SQLuedo/EntityFramework/LessonEntity.cs
+++ b/API_SQLuedo/EntityFramework/LessonEntity.cs
@@ -9,13 +9,8 @@ public class LessonEntity
     public string? Title { get; set; }
     public string? LastPublisher { get; set; }
     public DateOnly? LastEdit { get; set; }
+    public ICollection<ContentLessonEntity> Content { get; set; } = new List<ContentLessonEntity>();
 
-    public LessonEntity() { }
-
-    public LessonEntity(int id)
-    {
-        Id = id;
-    }
     public LessonEntity(int id, string title, string lastPublisher, DateOnly? lastEdit)
     {
         Id = id;
diff --git a/API_SQLuedo/EntityFramework/ParagraphEntity.cs b/API_SQLuedo/EntityFramework/ParagraphEntity.cs
index 4dc2277..ff1adc7 100644
--- a/API_SQLuedo/EntityFramework/ParagraphEntity.cs
+++ b/API_SQLuedo/EntityFramework/ParagraphEntity.cs
@@ -3,36 +3,31 @@
 namespace Entities;
 
 [Table("Paragraph")]
-public class ParagraphEntity
+public class ParagraphEntity : ContentLessonEntity
 {
-    public int Id { get; set; }
-    public string Title { get; set; }
-    public string Content { get; set; }
+    // ID
+    // ContentContent
+    // ContentTitle
+    // LessonId
     public string Info { get; set; }
     public string Query { get; set; }
     public string Comment { get; set; }
 
-    public ParagraphEntity() { }
-
-
-    public ParagraphEntity(int id)
+    public ParagraphEntity()
     {
-        Id = id;
     }
 
-    public ParagraphEntity(int id, string title, string content, string info, string query, string comment)
+    public ParagraphEntity(int id, string title, string content, string info, string query,
+        string comment, int idLesson) : base(id, idLesson, content, title)
     {
-        Id = id;
-        Title = title;
-        Content = content;
         Info = info;
         Query = query;
         Comment = comment;
     }
-    public ParagraphEntity(string title, string content, string info, string query, string comment)
+
+    public ParagraphEntity(string title, string content, string info, string query, string comment) : base(content,
+        title)
     {
-        Title = title;
-        Content = content;
         Info = info;
         Query = query;
         Comment = comment;
diff --git a/API_SQLuedo/Model/BlackList.cs b/API_SQLuedo/Model/BlackList.cs
index a53f1e9..002b5ba 100644
--- a/API_SQLuedo/Model/BlackList.cs
+++ b/API_SQLuedo/Model/BlackList.cs
@@ -1,14 +1,13 @@
-namespace ModelToEntities.Business
+namespace Model;
+
+public class BlackList
 {
-    public class BlackList
-    {
-        public string Email { get; set; }
-        public DateOnly ExpirationDate { get; set; }
+    public string Email { get; set; }
+    public DateOnly ExpirationDate { get; set; }
 
-        public BlackList(string email, DateOnly expirationDate)
-        {
-            Email = email;
-            ExpirationDate = expirationDate;
-        }
+    public BlackList(string email, DateOnly expirationDate)
+    {
+        Email = email;
+        ExpirationDate = expirationDate;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Model/ContentLesson.cs b/API_SQLuedo/Model/ContentLesson.cs
index 9ad8e3c..764d377 100644
--- a/API_SQLuedo/Model/ContentLesson.cs
+++ b/API_SQLuedo/Model/ContentLesson.cs
@@ -1,14 +1,24 @@
-namespace ModelToEntities.Business
+namespace Model;
+
+public abstract class ContentLesson
 {
-    public  class ContentLesson
+    public int Id { get; set; }
+    public string ContentContent { get; set; }
+    public string ContentTitle { get; set; }
+
+    public int LessonId { get; set; }
+
+    protected ContentLesson(string contentContent, string contentTitle)
+    {
+        ContentContent = contentContent;
+        ContentTitle = contentTitle;
+    }
+
+    protected ContentLesson(int id, string contentContent, string contentTitle, int lessonId)
     {
-        public ContentLesson(int lessonId, int lessonPartId)
-        {
-            LessonId = lessonId;
-            LessonPartId = lessonPartId;
-        }
-
-        public int LessonId { get; set; }
-        public int LessonPartId { get; set; }
+        Id = id;
+        ContentContent = contentContent;
+        ContentTitle = contentTitle;
+        LessonId = lessonId;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Model/Inquiry.cs b/API_SQLuedo/Model/Inquiry.cs
index 05a23c2..8aab55a 100644
--- a/API_SQLuedo/Model/Inquiry.cs
+++ b/API_SQLuedo/Model/Inquiry.cs
@@ -1,24 +1,23 @@
-namespace ModelToEntities.Business
+namespace Model;
+
+public class Inquiry
 {
-    public class Inquiry
-    {
-        public int Id { get; set; }
-        public string Title { get; set; }
-        public string Description { get; set; }
-        public bool IsUser { get; set; }
-        public int Database { get; set; }
-        public int InquiryTable { get; set; }
+    public int Id { get; set; }
+    public string Title { get; set; }
+    public string Description { get; set; }
+    public bool IsUser { get; set; }
+    public int Database { get; set; }
+    public int InquiryTable { get; set; }
 
-        public Inquiry() { }
+    public Inquiry() { }
 
-        public Inquiry(int id, string title, string description, bool isUser, int database, int inquiryTable)
-        {
-            Id = id;
-            Title = title;
-            Description = description;
-            IsUser = isUser;
-            Database = database;
-            InquiryTable = inquiryTable;
-        }
+    public Inquiry(int id, string title, string description, bool isUser, int database, int inquiryTable)
+    {
+        Id = id;
+        Title = title;
+        Description = description;
+        IsUser = isUser;
+        Database = database;
+        InquiryTable = inquiryTable;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Model/InquiryTable.cs b/API_SQLuedo/Model/InquiryTable.cs
index e75b4fe..060702a 100644
--- a/API_SQLuedo/Model/InquiryTable.cs
+++ b/API_SQLuedo/Model/InquiryTable.cs
@@ -1,18 +1,17 @@
-namespace ModelToEntities.Business
-{
-    public class InquiryTable
-    {
-        public int OwnerId { get; set; }
-        public string DatabaseName { get; set; }
-        public string ConnectionInfo { get; set; }
+namespace Model;
 
-        public InquiryTable() { }
-        public InquiryTable(int inquiryId, string databaseName, string connectionInfo)
-        {
-            OwnerId = inquiryId;
-            DatabaseName = databaseName;
-            ConnectionInfo = connectionInfo;
-        }
+public class InquiryTable
+{
+    public int OwnerId { get; set; }
+    public string DatabaseName { get; set; }
+    public string ConnectionInfo { get; set; }
 
+    public InquiryTable() { }
+    public InquiryTable(int inquiryId, string databaseName, string connectionInfo)
+    {
+        OwnerId = inquiryId;
+        DatabaseName = databaseName;
+        ConnectionInfo = connectionInfo;
     }
-}
+
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Model/Lesson.cs b/API_SQLuedo/Model/Lesson.cs
index 40f16aa..b9222d6 100644
--- a/API_SQLuedo/Model/Lesson.cs
+++ b/API_SQLuedo/Model/Lesson.cs
@@ -1,31 +1,25 @@
-namespace ModelToEntities.Business
-{
-    public class Lesson
-    {
-        public int Id { get; }
-        public string? Title { get; set; }
-        public string? LastPublisher { get; set; }
-        public DateOnly? LastEdit { get; set; }
+namespace Model;
 
-        public Lesson() { }
+public class Lesson
+{
+    public int Id { get; }
+    public string? Title { get; set; }
+    public string? LastPublisher { get; set; }
+    public DateOnly? LastEdit { get; set; }
+    public ICollection<ContentLesson> Content { get; set; } = new List<ContentLesson>();
 
-        public Lesson(int id)
-        {
-            Id = id;
-        }
-        public Lesson(int id, string title, string lastPublisher, DateOnly? lastEdit)
-        {
-            Id = id;
-            Title = title;
-            LastPublisher = lastPublisher;
-            LastEdit = lastEdit;
-        }
+    public Lesson(int id, string title, string lastPublisher, DateOnly? lastEdit)
+    {
+        Id = id;
+        Title = title;
+        LastPublisher = lastPublisher;
+        LastEdit = lastEdit;
+    }
 
-        public Lesson(string title, string lastPublisher, DateOnly? lastEdit)
-        {
-            Title = title;
-            LastPublisher = lastPublisher;
-            LastEdit = lastEdit;
-        }
+    public Lesson(string title, string lastPublisher, DateOnly? lastEdit)
+    {
+        Title = title;
+        LastPublisher = lastPublisher;
+        LastEdit = lastEdit;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Model/Notepad.cs b/API_SQLuedo/Model/Notepad.cs
index 7a36862..ce91168 100644
--- a/API_SQLuedo/Model/Notepad.cs
+++ b/API_SQLuedo/Model/Notepad.cs
@@ -1,26 +1,25 @@
-namespace ModelToEntities.Business
+namespace Model;
+
+public class Notepad
 {
-    public class Notepad
-    {
-        public int Id { get; set; }
-        public int UserId { get; set; }
-        public int InquiryId { get; set; }
-        public string Notes { get; set; }
+    public int Id { get; set; }
+    public int UserId { get; set; }
+    public int InquiryId { get; set; }
+    public string Notes { get; set; }
 
-        public Notepad() { }
+    public Notepad() { }
 
-        public Notepad(int id, int userId, int inquiryId, string notes)
-        {
-            Id = id;
-            UserId = userId;
-            InquiryId = inquiryId;
-            Notes = notes;
-        }
-        public Notepad(int userId,  int inquiryId,  string notes)
-        {
-            UserId = userId;
-            InquiryId = inquiryId;
-            Notes = notes;
-        }
+    public Notepad(int id, int userId, int inquiryId, string notes)
+    {
+        Id = id;
+        UserId = userId;
+        InquiryId = inquiryId;
+        Notes = notes;
+    }
+    public Notepad(int userId,  int inquiryId,  string notes)
+    {
+        UserId = userId;
+        InquiryId = inquiryId;
+        Notes = notes;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Model/Paragraph.cs b/API_SQLuedo/Model/Paragraph.cs
index 62585d8..583b37f 100644
--- a/API_SQLuedo/Model/Paragraph.cs
+++ b/API_SQLuedo/Model/Paragraph.cs
@@ -1,37 +1,24 @@
-namespace ModelToEntities.Business
-{
-    public class Paragraph
-    {
-        public int Id { get;  }
-        public string? Title { get; set; }
-        public string? Content { get; set; }
-        public string? Info { get; set; }
-        public string? Query { get; set; }
-        public string? Comment { get; set; }
+namespace Model;
 
-        public Paragraph() { }
+public class Paragraph : ContentLesson
+{
+    public string Info { get; set; }
+    public string Query { get; set; }
+    public string Comment { get; set; }
 
-        public Paragraph(int id)
-        {
-            Id = id;
-        }
+    public Paragraph(string title, string content, string info, string query, string comment) : base(content,
+        title)
+    {
+        Info = info;
+        Query = query;
+        Comment = comment;
+    }
 
-        public Paragraph(int id, string title, string content, string info, string query, string comment)
-        {
-            Id = id;
-            Title = title;
-            Content = content;
-            Info = info;
-            Query = query;
-            Comment = comment;
-        }
-        public Paragraph(string title, string content, string info, string query, string comment)
-        {
-            Title = title;
-            Content = content;
-            Info = info;
-            Query = query;
-            Comment = comment;
-        }
+    public Paragraph(int id, string title, string content, string info, string query, string comment, int lessonId) :
+        base(id, content, title, lessonId)
+    {
+        Info = info;
+        Query = query;
+        Comment = comment;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Model/Solution.cs b/API_SQLuedo/Model/Solution.cs
index fb17dca..bee801b 100644
--- a/API_SQLuedo/Model/Solution.cs
+++ b/API_SQLuedo/Model/Solution.cs
@@ -1,30 +1,29 @@
-namespace ModelToEntities.Business
+namespace Model;
+
+public class Solution
 {
-    public class Solution
+    public int OwnerId { get; set; }
+    public string MurdererFirstName { get; set; }
+    public string MurdererLastName { get; set; }
+    public string MurderPlace { get; set; }
+    public string MurderWeapon { get; set; }
+    public string Explanation { get; set; }
+    public Solution() { }
+    public Solution(int ownerId, string murdererFirstName, string murdererLastName, string murderPlace, string murderWeapon, string explanation)
     {
-        public int OwnerId { get; set; }
-        public string MurdererFirstName { get; set; }
-        public string MurdererLastName { get; set; }
-        public string MurderPlace { get; set; }
-        public string MurderWeapon { get; set; }
-        public string Explanation { get; set; }
-        public Solution() { }
-        public Solution(int ownerId, string murdererFirstName, string murdererLastName, string murderPlace, string murderWeapon, string explanation)
-        {
-            OwnerId = ownerId;
-            MurdererFirstName = murdererFirstName;
-            MurdererLastName = murdererLastName;
-            MurderPlace = murderPlace;
-            MurderWeapon = murderWeapon;
-            Explanation = explanation;
-        }
-        public Solution(string murdererFirstName, string murdererLastName, string murderPlace, string murderWeapon, string explanation)
-        {
-            MurdererFirstName = murdererFirstName;
-            MurdererLastName = murdererLastName;
-            MurderPlace = murderPlace;
-            MurderWeapon = murderWeapon;
-            Explanation = explanation;
-        }
+        OwnerId = ownerId;
+        MurdererFirstName = murdererFirstName;
+        MurdererLastName = murdererLastName;
+        MurderPlace = murderPlace;
+        MurderWeapon = murderWeapon;
+        Explanation = explanation;
     }
-}
+    public Solution(string murdererFirstName, string murdererLastName, string murderPlace, string murderWeapon, string explanation)
+    {
+        MurdererFirstName = murdererFirstName;
+        MurdererLastName = murdererLastName;
+        MurderPlace = murderPlace;
+        MurderWeapon = murderWeapon;
+        Explanation = explanation;
+    }
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Model/Success.cs b/API_SQLuedo/Model/Success.cs
index 1fe54cf..1301b0f 100644
--- a/API_SQLuedo/Model/Success.cs
+++ b/API_SQLuedo/Model/Success.cs
@@ -1,18 +1,17 @@
-namespace ModelToEntities.Business
+namespace Model;
+
+public class Success
 {
-    public class Success
-    {
-        public int UserId { get; set; }
-        public int InquiryId { get; set; }
-        public bool IsFinished { get; set; }
+    public int UserId { get; set; }
+    public int InquiryId { get; set; }
+    public bool IsFinished { get; set; }
 
-        public Success() { }
+    public Success() { }
 
-        public Success(int userId, int inquiryId, bool isFinished)
-        {
-            UserId = userId;
-            InquiryId = inquiryId;
-            IsFinished = isFinished;
-        }
+    public Success(int userId, int inquiryId, bool isFinished)
+    {
+        UserId = userId;
+        InquiryId = inquiryId;
+        IsFinished = isFinished;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Model/User.cs b/API_SQLuedo/Model/User.cs
index 2ee4ce3..8031378 100644
--- a/API_SQLuedo/Model/User.cs
+++ b/API_SQLuedo/Model/User.cs
@@ -1,21 +1,20 @@
-namespace ModelToEntities.Business
+namespace Model;
+
+public class User
 {
-    public class User
-    {
-        public int Id { get; set; }
-        public string Username { get; set; }
-        public string Password { get; set; }
-        public string Email { get; set; }
-        public bool IsAdmin { get; set; }
+    public int Id { get; set; }
+    public string Username { get; set; }
+    public string Password { get; set; }
+    public string Email { get; set; }
+    public bool IsAdmin { get; set; }
 
-        public User() { }
-        public User(int id, string username, string password, string email, bool isAdmin)
-        {
-            Id = id;
-            Username = username;
-            Password = password;
-            Email = email;
-            IsAdmin = isAdmin;
-        }
+    public User() { }
+    public User(int id, string username, string password, string email, bool isAdmin)
+    {
+        Id = id;
+        Username = username;
+        Password = password;
+        Email = email;
+        IsAdmin = isAdmin;
     }
-}
+}
\ No newline at end of file
diff --git a/API_SQLuedo/Shared/Mapper/BlackListMapper.cs b/API_SQLuedo/Shared/Mapper/BlackListMapper.cs
index 945d823..18d99c3 100644
--- a/API_SQLuedo/Shared/Mapper/BlackListMapper.cs
+++ b/API_SQLuedo/Shared/Mapper/BlackListMapper.cs
@@ -1,6 +1,6 @@
 using Dto;
 using Entities;
-using ModelToEntities.Business;
+using Model;
 
 namespace Shared.Mapper;
 
diff --git a/API_SQLuedo/Shared/Mapper/ContentLessonMapper.cs b/API_SQLuedo/Shared/Mapper/ContentLessonMapper.cs
deleted file mode 100644
index 1feb9a1..0000000
--- a/API_SQLuedo/Shared/Mapper/ContentLessonMapper.cs
+++ /dev/null
@@ -1,34 +0,0 @@
-using Dto;
-using Entities;
-using ModelToEntities.Business;
-
-namespace Shared.Mapper;
-
-public static class ContentLessonMapper
-{
-    public static ContentLesson FromDTOToModel(this ContentLessonDTO dto)
-    {
-        return new ContentLesson(dto.LessonId, dto.LessonPartId);
-    }
-
-    public static ContentLesson FromEntityToModel(this ContentLessonEntity ent)
-    {
-        return new ContentLesson(ent.LessonId, ent.LessonPartId);
-    }
-
-    public static ContentLessonDTO FromModelToDTO(this ContentLesson les)
-    {
-        return new ContentLessonDTO(les.LessonId, les.LessonPartId);
-    }
-
-    public static ContentLessonDTO FromEntityToDTO(this ContentLessonEntity ent)
-    {
-        return new ContentLessonDTO(ent.LessonId, ent.LessonPartId);
-    }
-
-    public static ContentLessonEntity FromModelToEntity(this ContentLesson les)
-    {
-        return new ContentLessonEntity(les.LessonId, new LessonEntity(les.LessonId), les.LessonPartId,
-            new ParagraphEntity(les.LessonPartId));
-    }
-}
\ No newline at end of file
diff --git a/API_SQLuedo/Shared/Mapper/InquiryMapper.cs b/API_SQLuedo/Shared/Mapper/InquiryMapper.cs
index 7ade449..ace6105 100644
--- a/API_SQLuedo/Shared/Mapper/InquiryMapper.cs
+++ b/API_SQLuedo/Shared/Mapper/InquiryMapper.cs
@@ -1,6 +1,6 @@
 using Dto;
 using Entities;
-using ModelToEntities.Business;
+using Model;
 
 namespace Shared.Mapper;
 
diff --git a/API_SQLuedo/Shared/Mapper/InquiryTableMapper.cs b/API_SQLuedo/Shared/Mapper/InquiryTableMapper.cs
index d5048a9..f11c4b8 100644
--- a/API_SQLuedo/Shared/Mapper/InquiryTableMapper.cs
+++ b/API_SQLuedo/Shared/Mapper/InquiryTableMapper.cs
@@ -1,6 +1,6 @@
 using Dto;
 using Entities;
-using ModelToEntities.Business;
+using Model;
 
 namespace Shared.Mapper;
 
diff --git a/API_SQLuedo/Shared/Mapper/LessonMapper.cs b/API_SQLuedo/Shared/Mapper/LessonMapper.cs
index 9edf99f..824c592 100644
--- a/API_SQLuedo/Shared/Mapper/LessonMapper.cs
+++ b/API_SQLuedo/Shared/Mapper/LessonMapper.cs
@@ -1,6 +1,6 @@
 using Dto;
 using Entities;
-using ModelToEntities.Business;
+using Model;
 
 namespace Shared.Mapper;
 
diff --git a/API_SQLuedo/Shared/Mapper/NotepadMapper.cs b/API_SQLuedo/Shared/Mapper/NotepadMapper.cs
index ba8aa08..5de18a8 100644
--- a/API_SQLuedo/Shared/Mapper/NotepadMapper.cs
+++ b/API_SQLuedo/Shared/Mapper/NotepadMapper.cs
@@ -1,6 +1,6 @@
 using Dto;
 using Entities;
-using ModelToEntities.Business;
+using Model;
 
 namespace Shared.Mapper;
 
diff --git a/API_SQLuedo/Shared/Mapper/ParagraphMapper.cs b/API_SQLuedo/Shared/Mapper/ParagraphMapper.cs
index 0afa24d..8cdc29e 100644
--- a/API_SQLuedo/Shared/Mapper/ParagraphMapper.cs
+++ b/API_SQLuedo/Shared/Mapper/ParagraphMapper.cs
@@ -1,6 +1,6 @@
 using Dto;
 using Entities;
-using ModelToEntities.Business;
+using Model;
 
 namespace Shared.Mapper;
 
@@ -8,31 +8,35 @@ public static class ParagraphMapper
 {
     public static Paragraph FromDTOToModel(ParagraphDTO dto)
     {
-        return new Paragraph(dto.Id, dto.Title, dto.Content, dto.Info, dto.Query, dto.Comment);
+        return new Paragraph(dto.ContentTitle, dto.ContentContent, dto.Info, dto.Query, dto.Comment);
     }
 
     public static Paragraph FromEntityToModel(ParagraphEntity model)
     {
-        return new Paragraph(model.Id, model.Title, model.Content, model.Info, model.Query, model.Comment);
+        return new Paragraph(model.ContentTitle, model.ContentContent, model.Info, model.Query, model.Comment);
     }
 
     public static ParagraphDTO FromEntityToDTO(ParagraphEntity model)
     {
-        return new ParagraphDTO(model.Id, model.Title, model.Content, model.Info, model.Query, model.Comment);
+        return new ParagraphDTO(model.Id, model.ContentTitle, model.ContentContent, model.Info, model.Query,
+            model.Comment, model.LessonId);
     }
 
     public static ParagraphDTO FromModelToDTO(Paragraph model)
     {
-        return new ParagraphDTO(model.Id, model.Title, model.Content, model.Info, model.Query, model.Comment);
+        return new ParagraphDTO(model.Id, model.ContentTitle, model.ContentContent, model.Info, model.Query,
+            model.Comment, model.LessonId);
     }
 
     public static ParagraphEntity FromDTOToEntity(ParagraphDTO dto)
     {
-        return new ParagraphEntity(dto.Id, dto.Title, dto.Content, dto.Info, dto.Query, dto.Comment);
+        return new ParagraphEntity(dto.Id, dto.ContentTitle, dto.ContentContent, dto.Info, dto.Query, dto.Comment,
+            dto.LessonId);
     }
 
-    public static Paragraph FromModelToEntity(Paragraph model)
+    public static ParagraphEntity FromModelToEntity(Paragraph model)
     {
-        return new Paragraph(model.Id, model.Title, model.Content, model.Info, model.Query, model.Comment);
+        return new ParagraphEntity(model.Id, model.ContentTitle, model.ContentContent, model.Info, model.Query,
+            model.Comment, model.LessonId);
     }
 }
\ No newline at end of file
diff --git a/API_SQLuedo/Shared/Mapper/SolutionMapper.cs b/API_SQLuedo/Shared/Mapper/SolutionMapper.cs
index 4d99120..098c56a 100644
--- a/API_SQLuedo/Shared/Mapper/SolutionMapper.cs
+++ b/API_SQLuedo/Shared/Mapper/SolutionMapper.cs
@@ -1,6 +1,6 @@
 using Dto;
 using Entities;
-using ModelToEntities.Business;
+using Model;
 
 namespace Shared.Mapper;
 
diff --git a/API_SQLuedo/Shared/Mapper/SuccessMapper.cs b/API_SQLuedo/Shared/Mapper/SuccessMapper.cs
index a6d0261..ea5ef02 100644
--- a/API_SQLuedo/Shared/Mapper/SuccessMapper.cs
+++ b/API_SQLuedo/Shared/Mapper/SuccessMapper.cs
@@ -1,6 +1,6 @@
 using Dto;
 using Entities;
-using ModelToEntities.Business;
+using Model;
 
 namespace Shared.Mapper;
 
diff --git a/API_SQLuedo/Shared/Mapper/UserMapper.cs b/API_SQLuedo/Shared/Mapper/UserMapper.cs
index a9d4350..f915699 100644
--- a/API_SQLuedo/Shared/Mapper/UserMapper.cs
+++ b/API_SQLuedo/Shared/Mapper/UserMapper.cs
@@ -1,6 +1,6 @@
 using Dto;
 using Entities;
-using ModelToEntities.Business;
+using Model;
 
 namespace Shared.Mapper;