diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/AbsolutePathAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/AbsolutePathAttribute.cs
new file mode 100644
index 00000000..16d42d07
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/AbsolutePathAttribute.cs
@@ -0,0 +1,22 @@
+using JetBrains.Annotations;
+using Microsoft.Extensions.DependencyInjection;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+using NexusMods.Paths;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds an <see cref="AbsolutePath"/>.
+/// </summary>
+[PublicAPI]
+public sealed class AbsolutePathAttribute(string ns, string name) : ScalarAttribute<AbsolutePath, string, Utf8InsensitiveSerializer>(ns, name)
+{
+    /// <inheritdoc/>
+    protected override string ToLowLevel(AbsolutePath value) => value.ToString();
+
+    /// <inheritdoc/>
+    protected override AbsolutePath FromLowLevel(string value, AttributeResolver resolver)
+    {
+        return resolver.ServiceProvider.GetRequiredService<IFileSystem>().FromUnsanitizedFullPath(value);
+    }
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/BackReferenceAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/BackReferenceAttribute.cs
index c33a5627..6cc15e09 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/Attributes/BackReferenceAttribute.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/BackReferenceAttribute.cs
@@ -1,4 +1,5 @@
-using NexusMods.MnemonicDB.Abstractions.Models;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.Models;
 // ReSharper disable UnusedTypeParameter
 #pragma warning disable CS9113 // Parameter is unread.
 
@@ -8,7 +9,5 @@ namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 /// A meta attribute the expresses a backwards reference some other
 /// model has
 /// </summary>
-public class BackReferenceAttribute<TOtherModel>(ReferenceAttribute referenceAttribute)
-where TOtherModel : IModelDefinition
-{
-}
+[PublicAPI]
+public sealed class BackReferenceAttribute<TOtherModel>(ReferenceAttribute referenceAttribute) where TOtherModel : IModelDefinition { }
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/BooleanAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/BooleanAttribute.cs
new file mode 100644
index 00000000..5431b9af
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/BooleanAttribute.cs
@@ -0,0 +1,17 @@
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds a boolean value.
+/// </summary>
+[PublicAPI]
+public sealed class BooleanAttribute(string ns, string name) : ScalarAttribute<bool, byte, UInt8Serializer>(ns, name)
+{
+    /// <inheritdoc/>
+    protected override byte ToLowLevel(bool value) => value ? (byte)1 : (byte)0;
+
+    /// <inheritdoc/>
+    protected override bool FromLowLevel(byte value, AttributeResolver resolver) => value == 1;
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/CardinalityAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/CardinalityAttribute.cs
index c5549a82..69a2e2c3 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/Attributes/CardinalityAttribute.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/CardinalityAttribute.cs
@@ -1,4 +1,4 @@
-using NexusMods.MnemonicDB.Abstractions.ElementComparers;
+using JetBrains.Annotations;
 using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
 
 namespace NexusMods.MnemonicDB.Abstractions.Attributes;
@@ -6,6 +6,7 @@ namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 /// <summary>
 /// Used to mark the cardinality of an attribute in the database
 /// </summary>
+[PublicAPI]
 public sealed class CardinalityAttribute(string ns, string name) : ScalarAttribute<Cardinality, byte, UInt8Serializer>(ns, name)
 {
     /// <inheritdoc />
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/CollectionAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/CollectionAttribute.cs
index ca8d0500..fca17541 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/Attributes/CollectionAttribute.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/CollectionAttribute.cs
@@ -1,4 +1,5 @@
-using NexusMods.MnemonicDB.Abstractions.IndexSegments;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.IndexSegments;
 using NexusMods.MnemonicDB.Abstractions.Models;
 
 namespace NexusMods.MnemonicDB.Abstractions.Attributes;
@@ -6,6 +7,7 @@ namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 /// <summary>
 /// An attribute that represents a collection of values
 /// </summary>
+[PublicAPI]
 public abstract class CollectionAttribute<TValue, TLowLevel, TSerializer>(string ns, string name)
     : Attribute<TValue, TLowLevel, TSerializer>(ns, name, cardinality: Cardinality.Many) 
     where TSerializer : IValueSerializer<TLowLevel>
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/EnumAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/EnumAttribute.cs
new file mode 100644
index 00000000..9d267d4c
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/EnumAttribute.cs
@@ -0,0 +1,53 @@
+using System;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds an enum value backed by an int32 value.
+/// </summary>
+[PublicAPI]
+public sealed class EnumAttribute<T>(string ns, string name) : ScalarAttribute<T, int, Int32Serializer>(ns, name)
+    where T : Enum
+{
+    /// <inheritdoc />
+    protected override int ToLowLevel(T value)
+    {
+        // NOTE(halgari): Looks like an allocation, but the cast to object is removed by the JIT since the type of
+        // T is a compile-time constant. Verified via sharpLab.io:
+        // https://sharplab.io/#v2:EYLgtghglgdgNAFxBAzmAPgAQEwEYCwAUJgAwAEAygBYQBOADgDITAB0ASgK4wJRgCmAbiJEA2gCkoCAOL8Y/WlADGACgQBPevwD2AMxUBZdQFEYnMAEoLAXTKYAzHexkAwgB4AKgD4yAdyoK/GQeZCBkpuZkAN5EZHHxDmSwCGQGKiEAbhAANpz8FtGx8cWYAOxkKskWKtrAAFb8SggWWblCRXEAvkTdhESJcpFGEWDRZABi2tpkALxkJHBkAEJ0s2S4ZJ2CQA=
+        return (int)(object)value;
+    }
+
+    /// <inheritdoc />
+    protected override T FromLowLevel(int value, AttributeResolver resolver)
+    {
+        // Same as ToLowLevel, the cast to object is removed by the JIT
+        return (T)(object)value;
+    }
+}
+
+/// <summary>
+/// An attribute that holds an enum value backed by a byte value.
+/// </summary>
+[PublicAPI]
+public sealed class EnumByteAttribute<T>(string ns, string name) : ScalarAttribute<T, byte, UInt8Serializer>(ns, name)
+    where T : Enum
+{
+    /// <inheritdoc />
+    protected override byte ToLowLevel(T value)
+    {
+        // NOTE(halgari): Looks like an allocation, but the cast to object is removed by the JIT since the type of
+        // T is a compile-time constant. Verified via sharpLab.io:
+        // https://sharplab.io/#v2:EYLgtghglgdgNAFxBAzmAPgAQEwEYCwAUJgAwAEAygBYQBOADgDITAB0ASgK4wJRgCmAbiJEA2gCkoCAOL8Y/WlADGACgQBPevwD2AMxUBZdQFEYnMAEoLAXTKYAzHexkAwgB4AKgD4yAdyoK/GQeZCBkpuZkAN5EZHHxDmSwCGQGKiEAbhAANpz8FtGx8cWYAOxkKskWKtrAAFb8SggWWblCRXEAvkTdhESJcpFGEWDRZABi2tpkALxkJHBkAEJ0s2S4ZJ2CQA=
+        return (byte)(object)value;
+    }
+
+    /// <inheritdoc />
+    protected override T FromLowLevel(byte value, AttributeResolver resolver)
+    {
+        // Same as ToLowLevel, the cast to object is removed by the JIT
+        return (T)(object)value;
+    }
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/Float32Attribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/Float32Attribute.cs
new file mode 100644
index 00000000..ca5798e9
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/Float32Attribute.cs
@@ -0,0 +1,17 @@
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds a float32 value.
+/// </summary>
+[PublicAPI]
+public sealed class Float32Attribute(string ns, string name) : ScalarAttribute<float, float, Float32Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override float ToLowLevel(float value) => value;
+
+    /// <inheritdoc />
+    protected override float FromLowLevel(float value, AttributeResolver resolver) => value;
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/Float64Attribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/Float64Attribute.cs
new file mode 100644
index 00000000..2c5b55ab
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/Float64Attribute.cs
@@ -0,0 +1,17 @@
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds a float64 value.
+/// </summary>
+[PublicAPI]
+public sealed class Float64Attribute(string ns, string name) : ScalarAttribute<double, double, Float64Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override double ToLowLevel(double value) => value;
+
+    /// <inheritdoc />
+    protected override double FromLowLevel(double value, AttributeResolver resolver) => value;
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/Int128Attribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/Int128Attribute.cs
new file mode 100644
index 00000000..d658ed1b
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/Int128Attribute.cs
@@ -0,0 +1,18 @@
+using System;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds an int128 value.
+/// </summary>
+[PublicAPI]
+public sealed class Int128Attribute(string ns, string name) : ScalarAttribute<Int128, Int128, Int128Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override Int128 ToLowLevel(Int128 value) => value;
+
+    /// <inheritdoc />
+    protected override Int128 FromLowLevel(Int128 value, AttributeResolver resolver) => value;
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/Int16Attribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/Int16Attribute.cs
new file mode 100644
index 00000000..83272038
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/Int16Attribute.cs
@@ -0,0 +1,17 @@
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds an int16 value.
+/// </summary>
+[PublicAPI]
+public sealed class Int16Attribute(string ns, string name) : ScalarAttribute<short, short, Int16Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override short ToLowLevel(short value) => value;
+
+    /// <inheritdoc />
+    protected override short FromLowLevel(short value, AttributeResolver resolver) => value;
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/Int32Attribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/Int32Attribute.cs
new file mode 100644
index 00000000..bc58c1af
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/Int32Attribute.cs
@@ -0,0 +1,17 @@
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds an int32 value.
+/// </summary>
+[PublicAPI]
+public sealed class Int32Attribute(string ns, string name) : ScalarAttribute<int, int, Int32Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override int ToLowLevel(int value) => value;
+
+    /// <inheritdoc />
+    protected override int FromLowLevel(int value, AttributeResolver resolver) => value;
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/Int64Attribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/Int64Attribute.cs
new file mode 100644
index 00000000..0eed6908
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/Int64Attribute.cs
@@ -0,0 +1,17 @@
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds an uint64 value.
+/// </summary>
+[PublicAPI]
+public sealed class Int64Attribute(string ns, string name) : ScalarAttribute<long, long, Int64Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override long ToLowLevel(long value) => value;
+
+    /// <inheritdoc />
+    protected override long FromLowLevel(long value, AttributeResolver resolver) => value;
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/MarkerAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/MarkerAttribute.cs
index 6122ef31..79d2be46 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/Attributes/MarkerAttribute.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/MarkerAttribute.cs
@@ -1,5 +1,5 @@
-using NexusMods.MnemonicDB.Abstractions.ElementComparers;
-using NexusMods.MnemonicDB.Abstractions.Models;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ElementComparers;
 using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
 
 namespace NexusMods.MnemonicDB.Abstractions.Attributes;
@@ -8,29 +8,12 @@ namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 /// An attribute that doesn't have a value, but is used to dispatch logic or to mark an entity
 /// as being of a certain type.
 /// </summary>
-/// <param name="ns"></param>
-/// <param name="name"></param>
-public class MarkerAttribute(string ns, string name) : Attribute<Null, Null, NullSerializer>(ns, name)
+[PublicAPI]
+public sealed class MarkerAttribute(string ns, string name) : ScalarAttribute<Null, Null, NullSerializer>(ns, name)
 {
     /// <inheritdoc />
     protected override Null ToLowLevel(Null value) => value;
 
     /// <inheritdoc />
     protected override Null FromLowLevel(Null value, AttributeResolver resolver) => value;
-
-    /// <summary>
-    /// Returns true if the entity contains the attribute.
-    /// </summary>
-    public bool Contains(IHasIdAndIndexSegment entity)
-    {
-        var segment = entity.IndexSegment;
-        var dbId = entity.Db.Connection.AttributeCache.GetAttributeId(Id);
-        for (var i = 0; i < segment.Count; i++)
-        {
-            var datom = segment[i];
-            if (datom.A != dbId) continue;
-            return true;
-        }
-        return false;
-    }
 }
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/ReferenceAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/ReferenceAttribute.cs
index fc7c8a45..4d873db6 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/Attributes/ReferenceAttribute.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/ReferenceAttribute.cs
@@ -1,4 +1,5 @@
-using NexusMods.MnemonicDB.Abstractions.Models;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.Models;
 using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
 
 namespace NexusMods.MnemonicDB.Abstractions.Attributes;
@@ -6,6 +7,7 @@ namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 /// <summary>
 /// An attribute that references another entity.
 /// </summary>
+[PublicAPI]
 public class ReferenceAttribute(string ns, string name) : ScalarAttribute<EntityId, EntityId, EntityIdSerializer>(ns, name)
 {
     /// <inheritdoc />
@@ -18,5 +20,6 @@ public class ReferenceAttribute(string ns, string name) : ScalarAttribute<Entity
 /// <summary>
 /// A typesafe reference attribute, that references entities of type T.
 /// </summary>
+[PublicAPI]
 public sealed class ReferenceAttribute<T>(string ns, string name) : ReferenceAttribute(ns, name)
 where T : IModelDefinition;
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/ReferencesAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/ReferencesAttribute.cs
index 29e16e28..af4a9504 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/Attributes/ReferencesAttribute.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/ReferencesAttribute.cs
@@ -1,4 +1,4 @@
-using NexusMods.MnemonicDB.Abstractions.ElementComparers;
+using JetBrains.Annotations;
 using NexusMods.MnemonicDB.Abstractions.Models;
 using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
 
@@ -7,6 +7,7 @@ namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 /// <summary>
 /// Represents a collection of references to other entities.
 /// </summary>
+[PublicAPI]
 public class ReferencesAttribute(string ns, string name) : CollectionAttribute<EntityId, EntityId, EntityIdSerializer>(ns, name)
 {
     /// <inheritdoc />
@@ -19,5 +20,6 @@ public class ReferencesAttribute(string ns, string name) : CollectionAttribute<E
 /// <summary>
 /// A typesafe reference attribute, that references entities of type T.
 /// </summary>
+[PublicAPI]
 public sealed class ReferencesAttribute<T>(string ns, string name) : ReferencesAttribute(ns, name)
 where T : IModelDefinition;
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/RelativePathAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/RelativePathAttribute.cs
new file mode 100644
index 00000000..f3f622ef
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/RelativePathAttribute.cs
@@ -0,0 +1,22 @@
+using JetBrains.Annotations;
+using Microsoft.Extensions.DependencyInjection;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+using NexusMods.Paths;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds an <see cref="RelativePath"/>.
+/// </summary>
+[PublicAPI]
+public sealed class RelativePathAttribute(string ns, string name) : ScalarAttribute<RelativePath, string, Utf8InsensitiveSerializer>(ns, name)
+{
+    /// <inheritdoc/>
+    protected override string ToLowLevel(RelativePath value) => value.ToString();
+
+    /// <inheritdoc/>
+    protected override RelativePath FromLowLevel(string value, AttributeResolver resolver)
+    {
+        return new RelativePath(value);
+    }
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/ScalarAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/ScalarAttribute.cs
index 00a7d263..28abfe98 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/Attributes/ScalarAttribute.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/ScalarAttribute.cs
@@ -1,6 +1,6 @@
 using System.Collections.Generic;
 using DynamicData.Kernel;
-using NexusMods.MnemonicDB.Abstractions.ElementComparers;
+using JetBrains.Annotations;
 using NexusMods.MnemonicDB.Abstractions.Models;
 
 namespace NexusMods.MnemonicDB.Abstractions.Attributes;
@@ -8,6 +8,7 @@ namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 /// <summary>
 /// An attribute that represents a scalar value, where there is a 1:1 ratio between the attribute and the value.
 /// </summary>
+[PublicAPI]
 public abstract class ScalarAttribute<TValue, TLowLevel, TSerializer>(string ns, string name) :
     Attribute<TValue, TLowLevel, TSerializer>(ns, name)
     where TSerializer : IValueSerializer<TLowLevel>
@@ -22,6 +23,14 @@ public bool IsOptional
         init => DeclaredOptional = value;
     }
 
+    /// <summary>
+    /// True whether the index segment contains this attribute.
+    /// </summary>
+    public bool Contains<T>(T entity) where T : IHasIdAndIndexSegment
+    {
+        return entity.IndexSegment.Contains(this);
+    }
+
     /// <summary>
     ///   Gets the value of the attribute from the entity.
     /// </summary>
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/SizeAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/SizeAttribute.cs
new file mode 100644
index 00000000..0010725f
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/SizeAttribute.cs
@@ -0,0 +1,18 @@
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+using NexusMods.Paths;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds an <see cref="Size"/>.
+/// </summary>
+[PublicAPI]
+public sealed class SizeAttribute(string ns, string name) : ScalarAttribute<Size, ulong, UInt64Serializer>(ns, name)
+{
+    /// <inheritdoc/>
+    protected override ulong ToLowLevel(Size value) => value.Value;
+
+    /// <inheritdoc/>
+    protected override Size FromLowLevel(ulong value, AttributeResolver resolver) => Size.From(value);
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/StringAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/StringAttribute.cs
index e7481e9c..daab05ca 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/Attributes/StringAttribute.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/StringAttribute.cs
@@ -1,10 +1,12 @@
-using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
 
 namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 
 /// <summary>
 /// An attribute that represents a string.
 /// </summary>
+[PublicAPI]
 public sealed class StringAttribute(string ns, string name) : ScalarAttribute<string, string, Utf8Serializer>(ns, name)
 {
     /// <inheritdoc />
diff --git a/tests/NexusMods.MnemonicDB.TestModel/Attributes/StringsAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/StringsAttribute.cs
similarity index 61%
rename from tests/NexusMods.MnemonicDB.TestModel/Attributes/StringsAttribute.cs
rename to src/NexusMods.MnemonicDB.Abstractions/Attributes/StringsAttribute.cs
index 9dd586f3..1bd33b1d 100644
--- a/tests/NexusMods.MnemonicDB.TestModel/Attributes/StringsAttribute.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/StringsAttribute.cs
@@ -1,13 +1,17 @@
-using NexusMods.MnemonicDB.Abstractions;
-using NexusMods.MnemonicDB.Abstractions.Attributes;
-using NexusMods.MnemonicDB.Abstractions.ElementComparers;
+using JetBrains.Annotations;
 using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
 
-namespace NexusMods.MnemonicDB.TestModel.Attributes;
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 
+/// <summary>
+/// An attribute that holds a collection of strings.
+/// </summary>
+[PublicAPI]
 public sealed class StringsAttribute(string ns, string name) : CollectionAttribute<string, string, Utf8Serializer>(ns, name)
 {
+    /// <inheritdoc/>
     protected override string ToLowLevel(string value) => value;
 
+    /// <inheritdoc/>
     protected override string FromLowLevel(string value, AttributeResolver resolver) => value;
 }
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/SymbolAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/SymbolAttribute.cs
index 4025a438..7506bf7a 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/Attributes/SymbolAttribute.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/SymbolAttribute.cs
@@ -1,11 +1,13 @@
-using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
 
 namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 
 /// <summary>
 /// An attribute that encodes a symbol.
 /// </summary>
-public class SymbolAttribute(string ns, string name) : ScalarAttribute<Symbol, string, AsciiSerializer>(ns, name)
+[PublicAPI]
+public sealed class SymbolAttribute(string ns, string name) : ScalarAttribute<Symbol, string, AsciiSerializer>(ns, name)
 {
     /// <inheritdoc />
     protected override string ToLowLevel(Symbol value) => value.Id;
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/TimestampAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/TimestampAttribute.cs
index 796b1ecd..48698209 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/Attributes/TimestampAttribute.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/TimestampAttribute.cs
@@ -1,6 +1,5 @@
 using System;
-using NexusMods.MnemonicDB.Abstractions.ElementComparers;
-using NexusMods.MnemonicDB.Abstractions.Models;
+using JetBrains.Annotations;
 using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
 
 namespace NexusMods.MnemonicDB.Abstractions.Attributes;
@@ -8,7 +7,8 @@ namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 /// <summary>
 /// An attribute that holds a timestamp
 /// </summary>
-public class TimestampAttribute(string ns, string name) : ScalarAttribute<DateTimeOffset, long, Int64Serializer>(ns, name)
+[PublicAPI]
+public sealed class TimestampAttribute(string ns, string name) : ScalarAttribute<DateTimeOffset, long, Int64Serializer>(ns, name)
 {
     /// <inheritdoc />
     protected override long ToLowLevel(DateTimeOffset value) => value.ToUnixTimeMilliseconds();
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/TxIdAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/TxIdAttribute.cs
new file mode 100644
index 00000000..2047a7c8
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/TxIdAttribute.cs
@@ -0,0 +1,17 @@
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds a <see cref="TxId"/>.
+/// </summary>
+[PublicAPI]
+public sealed class TxIdAttribute(string ns, string name) : ScalarAttribute<TxId, ulong, UInt64Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override ulong ToLowLevel(TxId value) => value.Value;
+
+    /// <inheritdoc />
+    protected override TxId FromLowLevel(ulong value, AttributeResolver resolver) => TxId.From(value);
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/UInt128Attribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/UInt128Attribute.cs
new file mode 100644
index 00000000..510a76cb
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/UInt128Attribute.cs
@@ -0,0 +1,18 @@
+using System;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds an uint128 value.
+/// </summary>
+[PublicAPI]
+public sealed class UInt128Attribute(string ns, string name) : ScalarAttribute<UInt128, UInt128, UInt128Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override UInt128 ToLowLevel(UInt128 value) => value;
+
+    /// <inheritdoc />
+    protected override UInt128 FromLowLevel(UInt128 value, AttributeResolver resolver) => value;
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/UInt16Attribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/UInt16Attribute.cs
new file mode 100644
index 00000000..1859091b
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/UInt16Attribute.cs
@@ -0,0 +1,17 @@
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds an uint16 value.
+/// </summary>
+[PublicAPI]
+public sealed class UInt16Attribute(string ns, string name) : ScalarAttribute<ushort, ushort, UInt16Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override ushort ToLowLevel(ushort value) => value;
+
+    /// <inheritdoc />
+    protected override ushort FromLowLevel(ushort value, AttributeResolver resolver) => value;
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/UInt32Attribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/UInt32Attribute.cs
new file mode 100644
index 00000000..6e67682f
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/UInt32Attribute.cs
@@ -0,0 +1,17 @@
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds an uint32 value.
+/// </summary>
+[PublicAPI]
+public sealed class UInt32Attribute(string ns, string name) : ScalarAttribute<uint, uint, UInt32Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override uint ToLowLevel(uint value) => value;
+
+    /// <inheritdoc />
+    protected override uint FromLowLevel(uint value, AttributeResolver resolver) => value;
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/ULongAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/UInt64Attribute.cs
similarity index 63%
rename from src/NexusMods.MnemonicDB.Abstractions/Attributes/ULongAttribute.cs
rename to src/NexusMods.MnemonicDB.Abstractions/Attributes/UInt64Attribute.cs
index ef4cc88c..2ab1edca 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/Attributes/ULongAttribute.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/UInt64Attribute.cs
@@ -1,11 +1,13 @@
+using JetBrains.Annotations;
 using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
 
 namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 
 /// <summary>
-/// UInt64 attribute (ulong)
+/// An attribute that holds an uint64 value.
 /// </summary>
-public sealed class ULongAttribute(string ns, string name) : ScalarAttribute<ulong, ulong, UInt64Serializer>(ns, name)
+[PublicAPI]
+public sealed class UInt64Attribute(string ns, string name) : ScalarAttribute<ulong, ulong, UInt64Serializer>(ns, name)
 {
     /// <inheritdoc />
     protected override ulong ToLowLevel(ulong value) => value;
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/UriAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/UriAttribute.cs
new file mode 100644
index 00000000..88a30428
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/UriAttribute.cs
@@ -0,0 +1,18 @@
+using System;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
+
+namespace NexusMods.MnemonicDB.Abstractions.Attributes;
+
+/// <summary>
+/// An attribute that holds a <see cref="Uri"/>.
+/// </summary>
+[PublicAPI]
+public sealed class UriAttribute(string ns, string name) : ScalarAttribute<Uri, string, Utf8Serializer>(ns, name)
+{
+    /// <inheritdoc />
+    protected override string ToLowLevel(Uri value) => value.ToString();
+
+    /// <inheritdoc />
+    protected override Uri FromLowLevel(string value, AttributeResolver resolver) => new(value);
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/Attributes/ValuesTagAttribute.cs b/src/NexusMods.MnemonicDB.Abstractions/Attributes/ValuesTagAttribute.cs
index ff70daac..0bb24c71 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/Attributes/ValuesTagAttribute.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/Attributes/ValuesTagAttribute.cs
@@ -1,4 +1,5 @@
-using NexusMods.MnemonicDB.Abstractions.ElementComparers;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.ElementComparers;
 using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
 
 namespace NexusMods.MnemonicDB.Abstractions.Attributes;
@@ -6,6 +7,7 @@ namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 /// <summary>
 /// An attribute that represents a value tag value
 /// </summary>
+[PublicAPI]
 public sealed class ValuesTagAttribute(string ns, string name) : ScalarAttribute<ValueTag, byte, UInt8Serializer>(ns, name)
 {
     /// <inheritdoc />
diff --git a/src/NexusMods.MnemonicDB.Abstractions/BuiltInEntities/Transaction.cs b/src/NexusMods.MnemonicDB.Abstractions/BuiltInEntities/Transaction.cs
index da7e31d6..955f5b68 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/BuiltInEntities/Transaction.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/BuiltInEntities/Transaction.cs
@@ -20,5 +20,5 @@ public partial class Transaction : IModelDefinition
     /// <summary>
     /// If this database is associated with a excision, this attribute will contain the number of datoms that were excised.
     /// </summary>
-    public static readonly ULongAttribute ExcisedDatoms = new(Namespace, "ExcisedDatoms") { IsOptional = true };
+    public static readonly UInt64Attribute ExcisedDatoms = new(Namespace, "ExcisedDatoms") { IsOptional = true };
 }
diff --git a/src/NexusMods.MnemonicDB.Abstractions/EntityExtensions.cs b/src/NexusMods.MnemonicDB.Abstractions/EntityExtensions.cs
new file mode 100644
index 00000000..d33207e2
--- /dev/null
+++ b/src/NexusMods.MnemonicDB.Abstractions/EntityExtensions.cs
@@ -0,0 +1,27 @@
+using System;
+using System.Linq;
+using JetBrains.Annotations;
+using NexusMods.MnemonicDB.Abstractions.BuiltInEntities;
+using NexusMods.MnemonicDB.Abstractions.Models;
+
+namespace NexusMods.MnemonicDB.Abstractions;
+
+/// <summary>
+/// Extension methods for entities.
+/// </summary>
+[PublicAPI]
+public static class EntityExtensions
+{
+    /// <summary>
+    /// Gets the timestamp of the transaction that created the model.
+    /// </summary>
+    public static DateTimeOffset GetCreatedAt<T>(this T model, DateTimeOffset defaultValue = default)
+        where T : IReadOnlyModel<T>
+    {
+        if (model.Count == 0) return defaultValue;
+        var minTx = model.Min(m => m.T);
+
+        var tx = new Transaction.ReadOnly(model.Db, EntityId.From(minTx.Value));
+        return Transaction.Timestamp.Get(tx);
+    }
+}
diff --git a/src/NexusMods.MnemonicDB.Abstractions/EntityId.cs b/src/NexusMods.MnemonicDB.Abstractions/EntityId.cs
index 895a37a9..4ab2d6c7 100644
--- a/src/NexusMods.MnemonicDB.Abstractions/EntityId.cs
+++ b/src/NexusMods.MnemonicDB.Abstractions/EntityId.cs
@@ -1,4 +1,7 @@
-using TransparentValueObjects;
+using System;
+using System.Globalization;
+using JetBrains.Annotations;
+using TransparentValueObjects;
 
 namespace NexusMods.MnemonicDB.Abstractions;
 
@@ -6,6 +9,7 @@ namespace NexusMods.MnemonicDB.Abstractions;
 ///     A unique identifier for an entity.
 /// </summary>
 [ValueObject<ulong>]
+[PublicAPI]
 public readonly partial struct EntityId : IAugmentWith<JsonAugment>
 {
     /// <summary>
@@ -38,4 +42,24 @@ public override string ToString()
     {
         return "EId:" + Value.ToString("X");
     }
+
+    /// <summary>
+    /// Tries to parse a hex string as an entity ID.
+    /// </summary>
+    public static bool TryParseFromHex(ReadOnlySpan<char> input, out EntityId id)
+    {
+        const string prefix = "EId:";
+
+        if (input.StartsWith(prefix))
+            input = input[prefix.Length..];
+
+        if (ulong.TryParse(input, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var result))
+        {
+            id = EntityId.From(result);
+            return true;
+        }
+
+        id = default;
+        return false;
+    }
 }
diff --git a/tests/NexusMods.MnemonicDB.TestModel/ArchiveFile.cs b/tests/NexusMods.MnemonicDB.TestModel/ArchiveFile.cs
index c65ead72..d45cd35b 100644
--- a/tests/NexusMods.MnemonicDB.TestModel/ArchiveFile.cs
+++ b/tests/NexusMods.MnemonicDB.TestModel/ArchiveFile.cs
@@ -1,4 +1,5 @@
-using NexusMods.MnemonicDB.Abstractions.Models;
+using NexusMods.MnemonicDB.Abstractions.Attributes;
+using NexusMods.MnemonicDB.Abstractions.Models;
 using NexusMods.MnemonicDB.TestModel.Attributes;
 
 namespace NexusMods.MnemonicDB.TestModel;
diff --git a/tests/NexusMods.MnemonicDB.TestModel/Attributes/AbsolutePathAttribute.cs b/tests/NexusMods.MnemonicDB.TestModel/Attributes/AbsolutePathAttribute.cs
deleted file mode 100644
index e0bb4e99..00000000
--- a/tests/NexusMods.MnemonicDB.TestModel/Attributes/AbsolutePathAttribute.cs
+++ /dev/null
@@ -1,17 +0,0 @@
-using Microsoft.Extensions.DependencyInjection;
-using NexusMods.MnemonicDB.Abstractions;
-using NexusMods.MnemonicDB.Abstractions.Attributes;
-using NexusMods.MnemonicDB.Abstractions.ElementComparers;
-using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
-using NexusMods.Paths;
-
-namespace NexusMods.MnemonicDB.TestModel.Attributes;
-
-public sealed class AbsolutePathAttribute(string ns, string name) : ScalarAttribute<AbsolutePath, string, Utf8Serializer>(ns, name)
-{ 
-    protected override string ToLowLevel(AbsolutePath value) 
-        => value.ToString();
-
-    protected override AbsolutePath FromLowLevel(string value, AttributeResolver resolver) 
-        => resolver.ServiceProvider.GetRequiredService<IFileSystem>().FromUnsanitizedFullPath(value);
-}
diff --git a/tests/NexusMods.MnemonicDB.TestModel/Attributes/RelativePathAttribute.cs b/tests/NexusMods.MnemonicDB.TestModel/Attributes/RelativePathAttribute.cs
deleted file mode 100644
index c040c513..00000000
--- a/tests/NexusMods.MnemonicDB.TestModel/Attributes/RelativePathAttribute.cs
+++ /dev/null
@@ -1,15 +0,0 @@
-using NexusMods.MnemonicDB.Abstractions;
-using NexusMods.MnemonicDB.Abstractions.Attributes;
-using NexusMods.MnemonicDB.Abstractions.ElementComparers;
-using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
-using NexusMods.Paths;
-
-namespace NexusMods.MnemonicDB.TestModel.Attributes;
-
-public sealed class RelativePathAttribute(string ns, string name) :
-    ScalarAttribute<RelativePath, string, Utf8InsensitiveSerializer>(ns, name)
-{
-    protected override string ToLowLevel(RelativePath value) => value.Path;
-
-    protected override RelativePath FromLowLevel(string value, AttributeResolver resolver) => new(value);
-}
diff --git a/tests/NexusMods.MnemonicDB.TestModel/Attributes/SizeAttribute.cs b/tests/NexusMods.MnemonicDB.TestModel/Attributes/SizeAttribute.cs
deleted file mode 100644
index e6edff0d..00000000
--- a/tests/NexusMods.MnemonicDB.TestModel/Attributes/SizeAttribute.cs
+++ /dev/null
@@ -1,14 +0,0 @@
-using NexusMods.MnemonicDB.Abstractions;
-using NexusMods.MnemonicDB.Abstractions.Attributes;
-using NexusMods.MnemonicDB.Abstractions.ElementComparers;
-using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
-using NexusMods.Paths;
-
-namespace NexusMods.MnemonicDB.TestModel.Attributes;
-
-public sealed class SizeAttribute(string ns, string name) : ScalarAttribute<Size, ulong, UInt64Serializer>(ns, name) {
-    protected override ulong ToLowLevel(Size value) => value.Value;
-
-    protected override Size FromLowLevel(ulong value, AttributeResolver resolver)
-        => Size.From(value);
-}
diff --git a/tests/NexusMods.MnemonicDB.TestModel/Attributes/UriAttribute.cs b/tests/NexusMods.MnemonicDB.TestModel/Attributes/UriAttribute.cs
deleted file mode 100644
index 8052d8fa..00000000
--- a/tests/NexusMods.MnemonicDB.TestModel/Attributes/UriAttribute.cs
+++ /dev/null
@@ -1,15 +0,0 @@
-using NexusMods.MnemonicDB.Abstractions;
-using NexusMods.MnemonicDB.Abstractions.Attributes;
-using NexusMods.MnemonicDB.Abstractions.ElementComparers;
-using NexusMods.MnemonicDB.Abstractions.ValueSerializers;
-
-namespace NexusMods.MnemonicDB.TestModel.Attributes;
-
-public sealed class UriAttribute(string ns, string name) : ScalarAttribute<Uri, string, Utf8Serializer>(ns, name)
-{
-    protected override string ToLowLevel(Uri value) 
-        => value.ToString();
-
-    protected override Uri FromLowLevel(string lowLevelValue, AttributeResolver resolver) 
-        => new(lowLevelValue);
-}
diff --git a/tests/NexusMods.MnemonicDB.Tests/MigrationTests.cs b/tests/NexusMods.MnemonicDB.Tests/MigrationTests.cs
index d67457f9..b9424a18 100644
--- a/tests/NexusMods.MnemonicDB.Tests/MigrationTests.cs
+++ b/tests/NexusMods.MnemonicDB.Tests/MigrationTests.cs
@@ -101,7 +101,7 @@ public async Task CanConvertValues()
         var aid = cache.GetAttributeId(Mod.Description.Id);
         cache.IsIndexed(aid).Should().BeFalse();
         
-        var withIndex = new ULongAttribute(Mod.Description.Id.Namespace, Mod.Description.Id.Name) { IsIndexed = true, IsOptional = false };
+        var withIndex = new UInt64Attribute(Mod.Description.Id.Namespace, Mod.Description.Id.Name) { IsIndexed = true, IsOptional = false };
         var prevTxId = Connection.Db.BasisTxId;
 
         await Connection.UpdateSchema(withIndex);
@@ -117,7 +117,7 @@ public async Task CanConvertValues()
     public async Task ConvertingValuesIncorrectlyFails()
     {
         await AddData();
-        var withIndex = new ULongAttribute(Mod.Source.Id.Namespace, Mod.Source.Id.Name) { IsIndexed = true, IsOptional = false };
+        var withIndex = new UInt64Attribute(Mod.Source.Id.Namespace, Mod.Source.Id.Name) { IsIndexed = true, IsOptional = false };
         var act = async () => await Connection.UpdateSchema(withIndex);
         await act.Should().ThrowAsync<InvalidOperationException>("Converting values for attribute Mod.Source from String to ULong where the source is a URI should fail");
     }