diff --git a/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Configurations/InstanceConfiguration.cs b/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Configurations/InstanceConfiguration.cs
index bd14aeeb..f9c4b038 100644
--- a/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Configurations/InstanceConfiguration.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Configurations/InstanceConfiguration.cs
@@ -53,10 +53,40 @@ public class InstanceConfiguration : IEntityTypeConfiguration<Instance>
             .HasForeignKey(b => b.InstanceId)
             .OnDelete(DeleteBehavior.Cascade);
 
+        builder.HasMany(i => i.NativeAlarmSourceOverrides)
+            .WithOne()
+            .HasForeignKey(o => o.InstanceId)
+            .OnDelete(DeleteBehavior.Cascade);
+
         builder.HasIndex(i => new { i.SiteId, i.UniqueName }).IsUnique();
     }
 }
 
+public class InstanceNativeAlarmSourceOverrideConfiguration : IEntityTypeConfiguration<InstanceNativeAlarmSourceOverride>
+{
+    /// <summary>Configures the EF Core mapping for <see cref="InstanceNativeAlarmSourceOverride"/>.</summary>
+    /// <param name="builder">The entity type builder.</param>
+    public void Configure(EntityTypeBuilder<InstanceNativeAlarmSourceOverride> builder)
+    {
+        builder.HasKey(o => o.Id);
+
+        builder.Property(o => o.SourceCanonicalName)
+            .IsRequired()
+            .HasMaxLength(400); // Larger than names to fit composed paths.
+
+        builder.Property(o => o.ConnectionNameOverride)
+            .HasMaxLength(200);
+
+        builder.Property(o => o.SourceReferenceOverride)
+            .HasMaxLength(1000);
+
+        builder.Property(o => o.ConditionFilterOverride)
+            .HasMaxLength(1000);
+
+        builder.HasIndex(o => new { o.InstanceId, o.SourceCanonicalName }).IsUnique();
+    }
+}
+
 public class InstanceAttributeOverrideConfiguration : IEntityTypeConfiguration<InstanceAttributeOverride>
 {
     /// <summary>Configures the EF Core mapping for <see cref="InstanceAttributeOverride"/>.</summary>
diff --git a/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Configurations/TemplateConfiguration.cs b/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Configurations/TemplateConfiguration.cs
index abff41d7..ac7c1e4a 100644
--- a/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Configurations/TemplateConfiguration.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Configurations/TemplateConfiguration.cs
@@ -58,6 +58,41 @@ public class TemplateConfiguration : IEntityTypeConfiguration<Template>
             .WithOne()
             .HasForeignKey(c => c.TemplateId)
             .OnDelete(DeleteBehavior.Cascade);
+
+        builder.HasMany(t => t.NativeAlarmSources)
+            .WithOne()
+            .HasForeignKey(s => s.TemplateId)
+            .OnDelete(DeleteBehavior.Cascade);
+    }
+}
+
+public class TemplateNativeAlarmSourceConfiguration : IEntityTypeConfiguration<TemplateNativeAlarmSource>
+{
+    /// <summary>Configures the EF Core mapping for <see cref="TemplateNativeAlarmSource"/>.</summary>
+    /// <param name="builder">The entity type builder.</param>
+    public void Configure(EntityTypeBuilder<TemplateNativeAlarmSource> builder)
+    {
+        builder.HasKey(s => s.Id);
+
+        builder.Property(s => s.Name)
+            .IsRequired()
+            .HasMaxLength(200);
+
+        builder.Property(s => s.Description)
+            .HasMaxLength(2000);
+
+        builder.Property(s => s.ConnectionName)
+            .IsRequired()
+            .HasMaxLength(200);
+
+        builder.Property(s => s.SourceReference)
+            .IsRequired()
+            .HasMaxLength(1000);
+
+        builder.Property(s => s.ConditionFilter)
+            .HasMaxLength(1000);
+
+        builder.HasIndex(s => new { s.TemplateId, s.Name }).IsUnique();
     }
 }
 
diff --git a/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/ScadaBridgeDbContext.cs b/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/ScadaBridgeDbContext.cs
index 19868d99..483c4f30 100644
--- a/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/ScadaBridgeDbContext.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/ScadaBridgeDbContext.cs
@@ -55,6 +55,8 @@ public class ScadaBridgeDbContext : DbContext, IDataProtectionKeyContext
     public DbSet<TemplateComposition> TemplateCompositions => Set<TemplateComposition>();
     /// <summary>Gets the set of template folders.</summary>
     public DbSet<TemplateFolder> TemplateFolders => Set<TemplateFolder>();
+    /// <summary>Gets the set of template native alarm source bindings.</summary>
+    public DbSet<TemplateNativeAlarmSource> TemplateNativeAlarmSources => Set<TemplateNativeAlarmSource>();
 
     // Instances
     /// <summary>Gets the set of instances.</summary>
@@ -65,6 +67,8 @@ public class ScadaBridgeDbContext : DbContext, IDataProtectionKeyContext
     public DbSet<InstanceAlarmOverride> InstanceAlarmOverrides => Set<InstanceAlarmOverride>();
     /// <summary>Gets the set of instance connection bindings.</summary>
     public DbSet<InstanceConnectionBinding> InstanceConnectionBindings => Set<InstanceConnectionBinding>();
+    /// <summary>Gets the set of instance native alarm source overrides.</summary>
+    public DbSet<InstanceNativeAlarmSourceOverride> InstanceNativeAlarmSourceOverrides => Set<InstanceNativeAlarmSourceOverride>();
     /// <summary>Gets the set of areas.</summary>
     public DbSet<Area> Areas => Set<Area>();
 
diff --git a/tests/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase.Tests/NativeAlarmSourceSchemaTests.cs b/tests/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase.Tests/NativeAlarmSourceSchemaTests.cs
new file mode 100644
index 00000000..d3cf5192
--- /dev/null
+++ b/tests/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase.Tests/NativeAlarmSourceSchemaTests.cs
@@ -0,0 +1,39 @@
+using Microsoft.EntityFrameworkCore;
+using ZB.MOM.WW.ScadaBridge.Commons.Entities.Templates;
+using ZB.MOM.WW.ScadaBridge.ConfigurationDatabase;
+
+namespace ZB.MOM.WW.ScadaBridge.ConfigurationDatabase.Tests;
+
+public class NativeAlarmSourceSchemaTests
+{
+    private static ScadaBridgeDbContext NewContext()
+    {
+        var opts = new DbContextOptionsBuilder<ScadaBridgeDbContext>()
+            .UseSqlite("DataSource=:memory:")
+            .Options;
+        var ctx = new ScadaBridgeDbContext(opts);
+        ctx.Database.OpenConnection();
+        ctx.Database.EnsureCreated();
+        return ctx;
+    }
+
+    [Fact]
+    public async Task TemplateNativeAlarmSource_PersistsViaTemplate()
+    {
+        using var ctx = NewContext();
+
+        var t = new Template("T1");
+        t.NativeAlarmSources.Add(new TemplateNativeAlarmSource("Src1") { ConnectionName = "C", SourceReference = "r" });
+        ctx.Templates.Add(t);
+        await ctx.SaveChangesAsync();
+
+        Assert.Single(ctx.TemplateNativeAlarmSources);
+    }
+
+    [Fact]
+    public async Task InstanceNativeAlarmSourceOverride_DbSetIsMapped()
+    {
+        using var ctx = NewContext();
+        Assert.Equal(0, await ctx.InstanceNativeAlarmSourceOverrides.CountAsync());
+    }
+}