First commit that builds.

code/MessengerBroker.Db/BrokerDbContext.cs

@@ -0,0 +1,32 @@
+using MessengerBroker.Db.Model;
+using Microsoft.EntityFrameworkCore;
+
+namespace MessengerBroker.Db
+{
+    public class BrokerDbContext : DbContext
+    {
+        private string connectionString;
+
+        public DbSet<Sync> Syncs { get; }
+
+        public DbSet<User> Users { get; }
+
+        public DbSet<Message> Messages { get; }
+
+        public BrokerDbContext(string connectionString)
+        {
+            this.connectionString = connectionString;
+        }
+
+        protected override void OnModelCreating(ModelBuilder modelBuilder)
+        {
+            base.OnModelCreating(modelBuilder);
+        }
+
+        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+        {
+            base.OnConfiguring(optionsBuilder);
+            optionsBuilder.UseSqlServer(this.connectionString);
+        }
+    }
+}

code/MessengerBroker.Db/MessengerBroker.Db.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.6" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="9.0.6" />
+  </ItemGroup>
+
+</Project>

code/MessengerBroker.Db/Model/Contracts/IForeignEntity.cs

@@ -0,0 +1,15 @@
+namespace MessengerBroker.Db.Model.Contracts
+{
+    public interface IForeignEntity
+    {
+        Guid Id { get; }
+
+        Guid BrokerId { get; }
+
+        bool IsDeleted { get; }
+
+        Sync? FirstSync { get; }
+
+        Sync? LastSync { get; }
+    }
+}

code/MessengerBroker.Db/Model/Message.cs

@@ -0,0 +1,9 @@
+namespace MessengerBroker.Db.Model
+{
+    public class Message
+    {
+        public Guid Id { get; set; }
+
+        public Guid BrokerId { get; set; }
+    }
+}

code/MessengerBroker.Db/Model/Sync.cs

@@ -0,0 +1,15 @@
+namespace MessengerBroker.Db.Model
+{
+    public class Sync
+    {
+        public int Id { get; set; }
+
+        public Guid BrokerId { get; set; }
+
+        public DateTime StartedUtc { get; set; }
+
+        public DateTime? FinishedUtc { get; set; }
+
+        public long? Changes { get; set; }
+    }
+}

code/MessengerBroker.Db/Model/User.cs

@@ -0,0 +1,11 @@
+using MessengerBroker.Db.Model.Contracts;
+
+namespace MessengerBroker.Db.Model
+{
+    public class User
+    {
+        public Guid Id { get; set; }
+
+        public Guid BrokerId { get; set; }
+    }
+}