Add a SharedTableConvention to set IndexesUniqueAcrossTables = false

src/EFCore.Jet/Metadata/Conventions/JetConventionSetBuilder.cs

@@ -36,6 +36,8 @@ namespace Microsoft.EntityFrameworkCore.Metadata.Conventions
                 new JetStoreGenerationConvention(Dependencies, RelationalDependencies));
             conventionSet.Replace<ValueGenerationConvention>(
                 new JetValueGenerationConvention(Dependencies, RelationalDependencies));
+            conventionSet.Replace<SharedTableConvention>(
+                new JetSharedTableConvention(Dependencies, RelationalDependencies));
 
             return conventionSet;
         }

src/EFCore.Jet/Metadata/Conventions/JetSharedTableConvention.cs

@@ -0,0 +1,30 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.EntityFrameworkCore.Metadata.Conventions.Infrastructure;
+using Microsoft.EntityFrameworkCore.Metadata.Internal;
+
+// ReSharper disable once CheckNamespace
+namespace Microsoft.EntityFrameworkCore.Metadata.Conventions;
+
+/// <summary>
+///     A convention that manipulates names of database objects for entity types that share a table to avoid clashes.
+/// </summary>
+public class JetSharedTableConvention : SharedTableConvention
+{
+    /// <summary>
+    ///     Creates a new instance of <see cref="JetSharedTableConvention" />.
+    /// </summary>
+    /// <param name="dependencies">Parameter object containing dependencies for this convention.</param>
+    /// <param name="relationalDependencies"> Parameter object containing relational dependencies for this convention.</param>
+    public JetSharedTableConvention(
+        ProviderConventionSetBuilderDependencies dependencies,
+        RelationalConventionSetBuilderDependencies relationalDependencies)
+        : base(dependencies, relationalDependencies)
+    {
+    }
+
+    /// <inheritdoc />
+    protected override bool IndexesUniqueAcrossTables
+        => false;
+}