diff --git a/HwProj.CoursesService/HwProj.CoursesService.API/Domains/MappingExtensions.cs b/HwProj.CoursesService/HwProj.CoursesService.API/Domains/MappingExtensions.cs
index 48ce7a8ea..0b536de7b 100644
--- a/HwProj.CoursesService/HwProj.CoursesService.API/Domains/MappingExtensions.cs
+++ b/HwProj.CoursesService/HwProj.CoursesService.API/Domains/MappingExtensions.cs
@@ -99,7 +99,7 @@ public static CourseDTO ToCourseDto(this Course course)
                 Name = course.Name,
                 GroupName = course.GroupName,
                 IsCompleted = course.IsCompleted,
-                MentorIds = course.MentorIds.Split('/', SplitOptions),
+                MentorIds = course.Mentors.Select(x => x.UserId).ToArray(),
                 IsOpen = course.IsOpen,
                 InviteCode = course.InviteCode,
                 CourseMates = course.CourseMates.Select(cm => cm.ToCourseMateViewModel()).ToArray(),
@@ -113,7 +113,7 @@ public static CoursePreview ToCoursePreview(this Course course)
                 Name = course.Name,
                 GroupName = course.GroupName,
                 IsCompleted = course.IsCompleted,
-                MentorIds = course.MentorIds.Split('/', SplitOptions),
+                MentorIds = course.Mentors.Select(x => x.UserId).ToArray(),
             };
 
         public static Criterion ToCriterion(this CriterionViewModel criterion) => new Criterion
diff --git a/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20240104183735_HomeworkCommonProperties.cs b/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20240104183735_HomeworkCommonProperties.cs
index eec4c39bd..00265b893 100644
--- a/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20240104183735_HomeworkCommonProperties.cs
+++ b/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20240104183735_HomeworkCommonProperties.cs
@@ -7,6 +7,18 @@ public partial class HomeworkCommonProperties : Migration
     {
         protected override void Up(MigrationBuilder migrationBuilder)
         {
+            migrationBuilder.Sql(@"
+                DECLARE @constraint NVARCHAR(200);
+                SELECT @constraint = dc.name
+                FROM sys.default_constraints dc
+                JOIN sys.columns c ON dc.parent_column_id = c.column_id 
+                    AND dc.parent_object_id = c.object_id
+                WHERE c.object_id = OBJECT_ID('Homeworks') AND c.name = 'Date';
+                
+                IF @constraint IS NOT NULL
+                    EXEC('ALTER TABLE Homeworks DROP CONSTRAINT ' + @constraint);
+            ");
+
             migrationBuilder.RenameColumn(
                 name: "Date",
                 table: "Homeworks",
@@ -47,5 +59,38 @@ protected override void Up(MigrationBuilder migrationBuilder)
                 nullable: false,
                 defaultValue: false);
         }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(name: "IsDeadlineStrict", table: "Homeworks");
+            migrationBuilder.DropColumn(name: "HasDeadline", table: "Homeworks");
+            migrationBuilder.DropColumn(name: "DeadlineDate", table: "Homeworks");
+
+            migrationBuilder.AlterColumn<bool>(
+                name: "HasDeadline",
+                table: "Tasks",
+                nullable: false,
+                oldClrType: typeof(bool),
+                oldNullable: true);
+
+            migrationBuilder.AlterColumn<bool>(
+                name: "IsDeadlineStrict",
+                table: "Tasks",
+                nullable: false,
+                oldClrType: typeof(bool),
+                oldNullable: true);
+
+            migrationBuilder.AlterColumn<DateTime>(
+                name: "PublicationDate",
+                table: "Tasks",
+                nullable: false,
+                oldClrType: typeof(DateTime),
+                oldNullable: true);
+
+            migrationBuilder.RenameColumn(
+                name: "PublicationDate",
+                table: "Homeworks",
+                newName: "Date");
+        }
     }
 }
diff --git a/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20261021133302_AddCourseMentorTable.Designer.cs b/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20261021133302_AddCourseMentorTable.Designer.cs
new file mode 100644
index 000000000..9d28fcba4
--- /dev/null
+++ b/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20261021133302_AddCourseMentorTable.Designer.cs
@@ -0,0 +1,516 @@
+// <auto-generated />
+using System;
+using HwProj.CoursesService.API.Models;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Metadata;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+#nullable disable
+
+namespace HwProj.CoursesService.API.Migrations
+{
+    [DbContext(typeof(CourseContext))]
+    [Migration("20261021133302_AddCourseMentorTable")]
+    partial class AddCourseMentorTable
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "9.0.9")
+                .HasAnnotation("Relational:MaxIdentifierLength", 128);
+
+            SqlServerModelBuilderExtensions.UseIdentityColumns(modelBuilder);
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Assignment", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<long>("CourseId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("MentorId")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("StudentId")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CourseId");
+
+                    b.ToTable("Assignments");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Course", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<string>("GroupName")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("InviteCode")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<bool>("IsCompleted")
+                        .HasColumnType("bit");
+
+                    b.Property<bool>("IsOpen")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("MentorIds")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Name")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Courses");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseFilter", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<string>("FilterJson")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("CourseFilters");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseMate", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<long>("CourseId")
+                        .HasColumnType("bigint");
+
+                    b.Property<bool>("IsAccepted")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("StudentId")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CourseId");
+
+                    b.ToTable("CourseMates");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseMentor", b =>
+                {
+                    b.Property<string>("UserId")
+                        .HasColumnType("nvarchar(450)");
+
+                    b.Property<long>("CourseId")
+                        .HasColumnType("bigint");
+
+                    b.HasKey("UserId", "CourseId");
+
+                    b.HasIndex("CourseId");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("CourseMentors");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Criterion", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<string>("Arguments")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<int>("MaxPoints")
+                        .HasColumnType("int");
+
+                    b.Property<string>("Name")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<long>("TaskId")
+                        .HasColumnType("bigint");
+
+                    b.Property<int>("Type")
+                        .HasColumnType("int");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TaskId");
+
+                    b.ToTable("Criteria");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Group", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<long>("CourseId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Name")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Groups");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.GroupMate", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<long>("GroupId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("StudentId")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(450)");
+
+                    b.HasKey("Id");
+
+                    b.HasAlternateKey("GroupId", "StudentId");
+
+                    b.ToTable("GroupMates");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Homework", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<long>("CourseId")
+                        .HasColumnType("bigint");
+
+                    b.Property<DateTime?>("DeadlineDate")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("Description")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<long?>("GroupId")
+                        .HasColumnType("bigint");
+
+                    b.Property<bool>("HasDeadline")
+                        .HasColumnType("bit");
+
+                    b.Property<bool>("IsDeadlineStrict")
+                        .HasColumnType("bit");
+
+                    b.Property<DateTime>("PublicationDate")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("Tags")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Title")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CourseId");
+
+                    b.ToTable("Homeworks");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.HomeworkTask", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<DateTime?>("DeadlineDate")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("Description")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<bool?>("HasDeadline")
+                        .HasColumnType("bit");
+
+                    b.Property<long>("HomeworkId")
+                        .HasColumnType("bigint");
+
+                    b.Property<bool>("IsBonusExplicit")
+                        .HasColumnType("bit");
+
+                    b.Property<bool?>("IsDeadlineStrict")
+                        .HasColumnType("bit");
+
+                    b.Property<int>("MaxRating")
+                        .HasColumnType("int");
+
+                    b.Property<DateTime?>("PublicationDate")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("Title")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("HomeworkId");
+
+                    b.ToTable("Tasks");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.StudentCharacteristics", b =>
+                {
+                    b.Property<long>("CourseMateId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Description")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Tags")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("CourseMateId");
+
+                    b.ToTable("StudentCharacteristics");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.TaskModel", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<long>("GroupId")
+                        .HasColumnType("bigint");
+
+                    b.Property<long>("TaskId")
+                        .HasColumnType("bigint");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("GroupId");
+
+                    b.ToTable("TasksModels");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.TaskQuestion", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<string>("Answer")
+                        .HasMaxLength(1000)
+                        .HasColumnType("nvarchar(1000)");
+
+                    b.Property<bool>("IsPrivate")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("LecturerId")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("StudentId")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<long>("TaskId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Text")
+                        .HasMaxLength(1000)
+                        .HasColumnType("nvarchar(1000)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TaskId");
+
+                    b.ToTable("Questions");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.UserToCourseFilter", b =>
+                {
+                    b.Property<long>("CourseId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Id")
+                        .HasColumnType("nvarchar(450)");
+
+                    b.Property<long>("CourseFilterId")
+                        .HasColumnType("bigint");
+
+                    b.HasKey("CourseId", "Id");
+
+                    b.HasIndex("CourseFilterId");
+
+                    b.ToTable("UserToCourseFilters");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Assignment", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Course", null)
+                        .WithMany("Assignments")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseMate", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Course", null)
+                        .WithMany("CourseMates")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseMentor", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Course", null)
+                        .WithMany("Mentors")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Criterion", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.HomeworkTask", "Task")
+                        .WithMany("Criteria")
+                        .HasForeignKey("TaskId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Task");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.GroupMate", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Group", null)
+                        .WithMany("GroupMates")
+                        .HasForeignKey("GroupId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Homework", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Course", null)
+                        .WithMany("Homeworks")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.HomeworkTask", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Homework", "Homework")
+                        .WithMany("Tasks")
+                        .HasForeignKey("HomeworkId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Homework");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.StudentCharacteristics", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.CourseMate", null)
+                        .WithOne("Characteristics")
+                        .HasForeignKey("HwProj.CoursesService.API.Models.StudentCharacteristics", "CourseMateId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.TaskModel", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Group", null)
+                        .WithMany("Tasks")
+                        .HasForeignKey("GroupId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.UserToCourseFilter", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.CourseFilter", "CourseFilter")
+                        .WithMany()
+                        .HasForeignKey("CourseFilterId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("CourseFilter");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Course", b =>
+                {
+                    b.Navigation("Assignments");
+
+                    b.Navigation("CourseMates");
+
+                    b.Navigation("Homeworks");
+
+                    b.Navigation("Mentors");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseMate", b =>
+                {
+                    b.Navigation("Characteristics");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Group", b =>
+                {
+                    b.Navigation("GroupMates");
+
+                    b.Navigation("Tasks");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Homework", b =>
+                {
+                    b.Navigation("Tasks");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.HomeworkTask", b =>
+                {
+                    b.Navigation("Criteria");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20261021133302_AddCourseMentorTable.cs b/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20261021133302_AddCourseMentorTable.cs
new file mode 100644
index 000000000..dbe525e64
--- /dev/null
+++ b/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20261021133302_AddCourseMentorTable.cs
@@ -0,0 +1,59 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace HwProj.CoursesService.API.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddCourseMentorTable : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "CourseMentors",
+                columns: table => new
+                {
+                    UserId = table.Column<string>(type: "nvarchar(450)", nullable: false),
+                    CourseId = table.Column<long>(type: "bigint", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_CourseMentors", x => new { x.UserId, x.CourseId });
+                    table.ForeignKey(
+                        name: "FK_CourseMentors_Courses_CourseId",
+                        column: x => x.CourseId,
+                        principalTable: "Courses",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+            
+            migrationBuilder.CreateIndex(
+                name: "IX_CourseMentors_CourseId",
+                table: "CourseMentors",
+                column: "CourseId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_CourseMentors_UserId",
+                table: "CourseMentors",
+                column: "UserId");
+            
+            migrationBuilder.Sql(@"
+                INSERT INTO CourseMentors (UserId, CourseId)
+                SELECT LTRIM(RTRIM(value)), c.Id
+                FROM Courses c
+                CROSS APPLY STRING_SPLIT(c.MentorIds, '/')
+                WHERE c.MentorIds IS NOT NULL 
+                  AND c.MentorIds != ''
+                  AND LTRIM(RTRIM(value)) != ''
+            ");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "CourseMentors");
+        }
+    }
+}
diff --git a/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20261022145922_DropMentorIds.Designer.cs b/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20261022145922_DropMentorIds.Designer.cs
new file mode 100644
index 000000000..cce404a3a
--- /dev/null
+++ b/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20261022145922_DropMentorIds.Designer.cs
@@ -0,0 +1,513 @@
+// <auto-generated />
+using System;
+using HwProj.CoursesService.API.Models;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Metadata;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+#nullable disable
+
+namespace HwProj.CoursesService.API.Migrations
+{
+    [DbContext(typeof(CourseContext))]
+    [Migration("20261022145922_DropMentorIds")]
+    partial class DropMentorIds
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "9.0.9")
+                .HasAnnotation("Relational:MaxIdentifierLength", 128);
+
+            SqlServerModelBuilderExtensions.UseIdentityColumns(modelBuilder);
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Assignment", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<long>("CourseId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("MentorId")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("StudentId")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CourseId");
+
+                    b.ToTable("Assignments");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Course", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<string>("GroupName")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("InviteCode")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<bool>("IsCompleted")
+                        .HasColumnType("bit");
+
+                    b.Property<bool>("IsOpen")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("Name")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Courses");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseFilter", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<string>("FilterJson")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("CourseFilters");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseMate", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<long>("CourseId")
+                        .HasColumnType("bigint");
+
+                    b.Property<bool>("IsAccepted")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("StudentId")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CourseId");
+
+                    b.ToTable("CourseMates");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseMentor", b =>
+                {
+                    b.Property<string>("UserId")
+                        .HasColumnType("nvarchar(450)");
+
+                    b.Property<long>("CourseId")
+                        .HasColumnType("bigint");
+
+                    b.HasKey("UserId", "CourseId");
+
+                    b.HasIndex("CourseId");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("CourseMentors");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Criterion", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<string>("Arguments")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<int>("MaxPoints")
+                        .HasColumnType("int");
+
+                    b.Property<string>("Name")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<long>("TaskId")
+                        .HasColumnType("bigint");
+
+                    b.Property<int>("Type")
+                        .HasColumnType("int");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TaskId");
+
+                    b.ToTable("Criteria");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Group", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<long>("CourseId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Name")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Groups");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.GroupMate", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<long>("GroupId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("StudentId")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(450)");
+
+                    b.HasKey("Id");
+
+                    b.HasAlternateKey("GroupId", "StudentId");
+
+                    b.ToTable("GroupMates");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Homework", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<long>("CourseId")
+                        .HasColumnType("bigint");
+
+                    b.Property<DateTime?>("DeadlineDate")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("Description")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<long?>("GroupId")
+                        .HasColumnType("bigint");
+
+                    b.Property<bool>("HasDeadline")
+                        .HasColumnType("bit");
+
+                    b.Property<bool>("IsDeadlineStrict")
+                        .HasColumnType("bit");
+
+                    b.Property<DateTime>("PublicationDate")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("Tags")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Title")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CourseId");
+
+                    b.ToTable("Homeworks");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.HomeworkTask", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<DateTime?>("DeadlineDate")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("Description")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<bool?>("HasDeadline")
+                        .HasColumnType("bit");
+
+                    b.Property<long>("HomeworkId")
+                        .HasColumnType("bigint");
+
+                    b.Property<bool>("IsBonusExplicit")
+                        .HasColumnType("bit");
+
+                    b.Property<bool?>("IsDeadlineStrict")
+                        .HasColumnType("bit");
+
+                    b.Property<int>("MaxRating")
+                        .HasColumnType("int");
+
+                    b.Property<DateTime?>("PublicationDate")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("Title")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("HomeworkId");
+
+                    b.ToTable("Tasks");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.StudentCharacteristics", b =>
+                {
+                    b.Property<long>("CourseMateId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Description")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("Tags")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("CourseMateId");
+
+                    b.ToTable("StudentCharacteristics");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.TaskModel", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<long>("GroupId")
+                        .HasColumnType("bigint");
+
+                    b.Property<long>("TaskId")
+                        .HasColumnType("bigint");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("GroupId");
+
+                    b.ToTable("TasksModels");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.TaskQuestion", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
+
+                    b.Property<string>("Answer")
+                        .HasMaxLength(1000)
+                        .HasColumnType("nvarchar(1000)");
+
+                    b.Property<bool>("IsPrivate")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("LecturerId")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("StudentId")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<long>("TaskId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Text")
+                        .HasMaxLength(1000)
+                        .HasColumnType("nvarchar(1000)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TaskId");
+
+                    b.ToTable("Questions");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.UserToCourseFilter", b =>
+                {
+                    b.Property<long>("CourseId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Id")
+                        .HasColumnType("nvarchar(450)");
+
+                    b.Property<long>("CourseFilterId")
+                        .HasColumnType("bigint");
+
+                    b.HasKey("CourseId", "Id");
+
+                    b.HasIndex("CourseFilterId");
+
+                    b.ToTable("UserToCourseFilters");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Assignment", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Course", null)
+                        .WithMany("Assignments")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseMate", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Course", null)
+                        .WithMany("CourseMates")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseMentor", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Course", null)
+                        .WithMany("Mentors")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Criterion", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.HomeworkTask", "Task")
+                        .WithMany("Criteria")
+                        .HasForeignKey("TaskId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Task");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.GroupMate", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Group", null)
+                        .WithMany("GroupMates")
+                        .HasForeignKey("GroupId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Homework", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Course", null)
+                        .WithMany("Homeworks")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.HomeworkTask", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Homework", "Homework")
+                        .WithMany("Tasks")
+                        .HasForeignKey("HomeworkId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Homework");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.StudentCharacteristics", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.CourseMate", null)
+                        .WithOne("Characteristics")
+                        .HasForeignKey("HwProj.CoursesService.API.Models.StudentCharacteristics", "CourseMateId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.TaskModel", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Group", null)
+                        .WithMany("Tasks")
+                        .HasForeignKey("GroupId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.UserToCourseFilter", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.CourseFilter", "CourseFilter")
+                        .WithMany()
+                        .HasForeignKey("CourseFilterId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("CourseFilter");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Course", b =>
+                {
+                    b.Navigation("Assignments");
+
+                    b.Navigation("CourseMates");
+
+                    b.Navigation("Homeworks");
+
+                    b.Navigation("Mentors");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseMate", b =>
+                {
+                    b.Navigation("Characteristics");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Group", b =>
+                {
+                    b.Navigation("GroupMates");
+
+                    b.Navigation("Tasks");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.Homework", b =>
+                {
+                    b.Navigation("Tasks");
+                });
+
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.HomeworkTask", b =>
+                {
+                    b.Navigation("Criteria");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20261022145922_DropMentorIds.cs b/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20261022145922_DropMentorIds.cs
new file mode 100644
index 000000000..969202d5c
--- /dev/null
+++ b/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/20261022145922_DropMentorIds.cs
@@ -0,0 +1,28 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace HwProj.CoursesService.API.Migrations
+{
+    /// <inheritdoc />
+    public partial class DropMentorIds : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "MentorIds",
+                table: "Courses");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "MentorIds",
+                table: "Courses",
+                type: "nvarchar(max)",
+                nullable: true);
+        }
+    }
+}
diff --git a/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/CourseContextModelSnapshot.cs b/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/CourseContextModelSnapshot.cs
index 199917cf8..881609de1 100644
--- a/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/CourseContextModelSnapshot.cs
+++ b/HwProj.CoursesService/HwProj.CoursesService.API/Migrations/CourseContextModelSnapshot.cs
@@ -66,9 +66,6 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                     b.Property<bool>("IsOpen")
                         .HasColumnType("bit");
 
-                    b.Property<string>("MentorIds")
-                        .HasColumnType("nvarchar(max)");
-
                     b.Property<string>("Name")
                         .HasColumnType("nvarchar(max)");
 
@@ -117,6 +114,23 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                     b.ToTable("CourseMates");
                 });
 
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseMentor", b =>
+                {
+                    b.Property<string>("UserId")
+                        .HasColumnType("nvarchar(450)");
+
+                    b.Property<long>("CourseId")
+                        .HasColumnType("bigint");
+
+                    b.HasKey("UserId", "CourseId");
+
+                    b.HasIndex("CourseId");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("CourseMentors");
+                });
+
             modelBuilder.Entity("HwProj.CoursesService.API.Models.Criterion", b =>
                 {
                     b.Property<long>("Id")
@@ -125,12 +139,12 @@ protected override void BuildModel(ModelBuilder modelBuilder)
 
                     SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<long>("Id"));
 
-                    b.Property<int>("MaxPoints")
-                        .HasColumnType("int");
-
                     b.Property<string>("Arguments")
                         .HasColumnType("nvarchar(max)");
 
+                    b.Property<int>("MaxPoints")
+                        .HasColumnType("int");
+
                     b.Property<string>("Name")
                         .HasColumnType("nvarchar(max)");
 
@@ -380,6 +394,15 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .IsRequired();
                 });
 
+            modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseMentor", b =>
+                {
+                    b.HasOne("HwProj.CoursesService.API.Models.Course", null)
+                        .WithMany("Mentors")
+                        .HasForeignKey("CourseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
             modelBuilder.Entity("HwProj.CoursesService.API.Models.Criterion", b =>
                 {
                     b.HasOne("HwProj.CoursesService.API.Models.HomeworkTask", "Task")
@@ -456,6 +479,8 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                     b.Navigation("CourseMates");
 
                     b.Navigation("Homeworks");
+
+                    b.Navigation("Mentors");
                 });
 
             modelBuilder.Entity("HwProj.CoursesService.API.Models.CourseMate", b =>
diff --git a/HwProj.CoursesService/HwProj.CoursesService.API/Models/Course.cs b/HwProj.CoursesService/HwProj.CoursesService.API/Models/Course.cs
index 255241668..f09d9713a 100644
--- a/HwProj.CoursesService/HwProj.CoursesService.API/Models/Course.cs
+++ b/HwProj.CoursesService/HwProj.CoursesService.API/Models/Course.cs
@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
 using HwProj.Repositories.Net8;
 
@@ -12,7 +13,7 @@ public class Course : IEntity<long>
         public bool IsOpen { get; set; }
         public string InviteCode { get; set; }
         public bool IsCompleted { get; set; }
-        public string MentorIds { get; set; }
+        public List<CourseMentor> Mentors { get; set; } = new List<CourseMentor>();
         public List<CourseMate> CourseMates { get; set; } = new List<CourseMate>();
         public List<Homework> Homeworks { get; set; } = new List<Homework>();
         public List<Assignment> Assignments { get; set; } = new List<Assignment>();
diff --git a/HwProj.CoursesService/HwProj.CoursesService.API/Models/CourseContext.cs b/HwProj.CoursesService/HwProj.CoursesService.API/Models/CourseContext.cs
index c32220254..c4f3418a9 100644
--- a/HwProj.CoursesService/HwProj.CoursesService.API/Models/CourseContext.cs
+++ b/HwProj.CoursesService/HwProj.CoursesService.API/Models/CourseContext.cs
@@ -18,6 +18,7 @@ public sealed class CourseContext : DbContext
         public DbSet<UserToCourseFilter> UserToCourseFilters { get; set; }
         public DbSet<TaskQuestion> Questions { get; set; }
         public DbSet<Criterion> Criteria { get; set; }
+        public DbSet<CourseMentor> CourseMentors { get; set; }
 
         public CourseContext(DbContextOptions options)
             : base(options)
@@ -30,6 +31,10 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
             modelBuilder.Entity<Assignment>().HasIndex(a => a.CourseId);
             modelBuilder.Entity<UserToCourseFilter>().HasKey(u => new { u.CourseId, u.Id });
             modelBuilder.Entity<TaskQuestion>().HasIndex(t => t.TaskId);
+
+            modelBuilder.Entity<CourseMentor>().HasKey(m => new { m.UserId, m.CourseId });
+            modelBuilder.Entity<CourseMentor>().HasIndex(m => m.UserId);
+            modelBuilder.Entity<CourseMentor>().HasIndex(m => m.CourseId);
         }
     }
 }
diff --git a/HwProj.CoursesService/HwProj.CoursesService.API/Models/CourseMentor.cs b/HwProj.CoursesService/HwProj.CoursesService.API/Models/CourseMentor.cs
new file mode 100644
index 000000000..0f0b51420
--- /dev/null
+++ b/HwProj.CoursesService/HwProj.CoursesService.API/Models/CourseMentor.cs
@@ -0,0 +1,8 @@
+namespace HwProj.CoursesService.API.Models
+{
+    public class CourseMentor
+    {
+        public string UserId { get; set; }
+        public long CourseId { get; set; }
+    }
+}
diff --git a/HwProj.CoursesService/HwProj.CoursesService.API/Repositories/CoursesRepository.cs b/HwProj.CoursesService/HwProj.CoursesService.API/Repositories/CoursesRepository.cs
index 2c1c83e95..e8f7925db 100644
--- a/HwProj.CoursesService/HwProj.CoursesService.API/Repositories/CoursesRepository.cs
+++ b/HwProj.CoursesService/HwProj.CoursesService.API/Repositories/CoursesRepository.cs
@@ -15,12 +15,14 @@ public CoursesRepository(CourseContext context)
 
         public Task<Course?> GetWithCourseMates(long id) =>
             Context.Set<Course>()
+                .Include(c => c.Mentors)
                 .Include(c => c.CourseMates)
                 .AsNoTracking()
                 .FirstOrDefaultAsync(c => c.Id == id);
 
         public async Task<Course?> GetWithHomeworksAsync(long id)
             => await Context.Set<Course>()
+                .Include(c => c.Mentors)
                 .Include(c => c.Homeworks)
                 .ThenInclude(h => h.Tasks)
                 .AsNoTracking()
@@ -28,9 +30,9 @@ public CoursesRepository(CourseContext context)
 
         public async Task<Course?> GetWithCourseMatesAndHomeworksAsync(long id, bool withCriteria)
         {
-            // Раздельные запросы вместо одного JOIN, иначе строки студентов перемножаются со строками задач
             var query = Context.Set<Course>()
                 .AsNoTracking()
+                .Include(c => c.Mentors)
                 .AsSplitQuery()
                 .Include(c => c.CourseMates)
                 .ThenInclude(c => c.Characteristics)
@@ -42,10 +44,15 @@ public CoursesRepository(CourseContext context)
                 : await query.FirstOrDefaultAsync(c => c.Id == id);
         }
 
-        public Task<string> GetMentorIdsAsync(long id) =>
-            Context.Set<Course>()
-                .Where(c => c.Id == id)
-                .Select(c => c.MentorIds)
-                .SingleAsync();
+        public IQueryable<Course> GetAllWithCourseMatesAndHomeworks()
+        {
+            return Context.Set<Course>()
+                .Include(c => c.Mentors)
+                .Include(c => c.CourseMates)
+                .ThenInclude(c => c.Characteristics)
+                .Include(c => c.Homeworks)
+                .ThenInclude(c => c.Tasks)
+                .AsNoTracking();
+        }
     }
 }
diff --git a/HwProj.CoursesService/HwProj.CoursesService.API/Repositories/ICoursesRepository.cs b/HwProj.CoursesService/HwProj.CoursesService.API/Repositories/ICoursesRepository.cs
index 9b9a9817e..adc8b0740 100644
--- a/HwProj.CoursesService/HwProj.CoursesService.API/Repositories/ICoursesRepository.cs
+++ b/HwProj.CoursesService/HwProj.CoursesService.API/Repositories/ICoursesRepository.cs
@@ -9,6 +9,6 @@ public interface ICoursesRepository : ICrudRepository<Course, long>
         Task<Course?> GetWithCourseMates(long id);
         Task<Course?> GetWithHomeworksAsync(long id);
         Task<Course?> GetWithCourseMatesAndHomeworksAsync(long id, bool withCriteria = false);
-        Task<string> GetMentorIdsAsync(long id);
+
     }
 }
diff --git a/HwProj.CoursesService/HwProj.CoursesService.API/Services/CoursesService.cs b/HwProj.CoursesService/HwProj.CoursesService.API/Services/CoursesService.cs
index cdd757c7c..306ec36ee 100644
--- a/HwProj.CoursesService/HwProj.CoursesService.API/Services/CoursesService.cs
+++ b/HwProj.CoursesService/HwProj.CoursesService.API/Services/CoursesService.cs
@@ -102,7 +102,7 @@ public async Task<long> AddAsync(CreateCourseViewModel courseViewModel, string m
             {
                 baseCourse = await _coursesRepository.GetWithHomeworksAsync(courseViewModel.BaseCourseId.Value);
                 if (baseCourse == null) throw new InvalidOperationException("Базовый курс не найден");
-                if (!baseCourse.MentorIds.Contains(mentorId))
+                if (!baseCourse.Mentors.Any(m => m.UserId == mentorId))
                     throw new ForbiddenException(
                         $"Пользователь с id{mentorId} не является ментором указанного базового курса");
             }
@@ -150,7 +150,7 @@ private async Task<Course> AddFromTemplateAsync(CourseTemplate courseTemplate, L
             using var transactionScope = new TransactionScope(TransactionScopeAsyncFlowOption.Enabled);
 
             var course = courseTemplate.ToCourse();
-            course.MentorIds = mentorId;
+            course.Mentors = new List<CourseMentor> { new CourseMentor { UserId = mentorId } };
             course.InviteCode = Guid.NewGuid().ToString();
             var courseId = await _coursesRepository.AddAsync(course);
 
@@ -178,7 +178,7 @@ private async Task<Course> AddFromTemplateAsync(CourseTemplate courseTemplate, L
                     {
                         CourseId = courseId,
                         CourseName = course.Name,
-                        MentorIds = course.MentorIds,
+                        MentorIds = string.Join("/", course.Mentors.Select(m => m.UserId)),
                         StudentId = student.StudentId
                     });
                 }
@@ -222,11 +222,17 @@ public async Task<bool> AddStudentAsync(long courseId, string studentId)
             };
 
             await _courseMatesRepository.AddAsync(courseMate);
+
+            var mentorIds = await _context.CourseMentors
+                .Where(m => m.CourseId == courseId)
+                .Select(m => m.UserId)
+                .ToArrayAsync();
+
             _eventBus.Publish(new NewCourseMateEvent
             {
                 CourseId = courseId,
                 CourseName = course.Name,
-                MentorIds = course.MentorIds,
+                MentorIds = string.Join("/", mentorIds),
                 StudentId = studentId,
                 IsAccepted = false
             });
@@ -244,11 +250,16 @@ public async Task<bool> AcceptCourseMateAsync(long courseId, string studentId)
 
             await _courseMatesRepository.UpdateAsync(cm.Id, cm => new CourseMate { IsAccepted = true });
 
+            var mentorIds = await _context.CourseMentors
+                .Where(m => m.CourseId == courseId)
+                .Select(m => m.UserId)
+                .ToArrayAsync();
+
             _eventBus.Publish(new LecturerAcceptToCourseEvent
             {
                 CourseId = courseId,
                 CourseName = course.Name,
-                MentorIds = course.MentorIds,
+                MentorIds = string.Join("/", mentorIds),
                 StudentId = studentId
             });
 
@@ -265,11 +276,16 @@ public async Task<bool> RejectCourseMateAsync(long courseId, string studentId)
 
             await _courseMatesRepository.DeleteAsync(cm.Id);
 
+            var mentorIds = await _context.CourseMentors
+                .Where(m => m.CourseId == courseId)
+                .Select(m => m.UserId)
+                .ToArrayAsync();
+
             _eventBus.Publish(new LecturerRejectToCourseEvent
             {
                 CourseId = courseId,
                 CourseName = course.Name,
-                MentorIds = course.MentorIds,
+                MentorIds = string.Join("/", mentorIds),
                 StudentId = studentId
             });
             return true;
@@ -280,10 +296,11 @@ public async Task<CourseDTO[]> GetUserCoursesAsync(string userId, string role)
             var isMentor = role == Roles.LecturerRole || role == Roles.ExpertRole;
 
             var courses = isMentor
-                ? _coursesRepository.FindAll(c => c.MentorIds.Contains(userId))
+                ? _coursesRepository.FindAll(c => c.Mentors.Any(m => m.UserId == userId))
                 : _coursesRepository.FindAll(c => c.CourseMates.Any(cm => cm.IsAccepted && cm.StudentId == userId));
 
             var coursesWithValues = await courses
+                .Include(c => c.Mentors)
                 .AsSplitQuery()
                 .Include(c => c.CourseMates)
                 .Include(c => c.Homeworks.OrderBy(h => h.Id)).ThenInclude(t => t.Tasks.OrderBy(x => x.Id))
@@ -311,13 +328,18 @@ public async Task<bool> AcceptLecturerAsync(long courseId, string lecturerEmail,
         {
             var course = await _coursesRepository.GetAsync(courseId);
             if (course == null) return false;
-            if (!course.MentorIds.Contains(lecturerId))
+
+            var alreadyMentor = await _context.CourseMentors
+                .AnyAsync(m => m.CourseId == courseId && m.UserId == lecturerId);
+
+            if (!alreadyMentor)
             {
-                var newMentors = course.MentorIds + "/" + lecturerId;
-                await _coursesRepository.UpdateAsync(courseId, с => new Course
+                await _context.CourseMentors.AddAsync(new CourseMentor
                 {
-                    MentorIds = newMentors,
+                    CourseId = courseId,
+                    UserId = lecturerId
                 });
+                await _context.SaveChangesAsync();
 
                 _eventBus.Publish(new LecturerInvitedToCourseEvent
                 {
@@ -335,8 +357,10 @@ public async Task<bool> AcceptLecturerAsync(long courseId, string lecturerEmail,
 
         public async Task<string[]> GetCourseLecturers(long courseId)
         {
-            var mentorIds = await _coursesRepository.GetMentorIdsAsync(courseId);
-            return mentorIds.Split('/');
+            return await _context.CourseMentors
+                .Where(m => m.CourseId == courseId)
+                .Select(m => m.UserId)
+                .ToArrayAsync();
         }
 
         public async Task<bool> HasStudent(long courseId, string studentId)