dotnet/efcore · error · InvalidOperationException

Both ' ' and ' ' are mapped to the view ' '. All the entity…

Error message

Both '{entityType}' and '{otherEntityType}' are mapped to the view '{view}'. All the entity types in a non-TPH hierarchy (one that doesn't have a discriminator) must be mapped to different views. See https://go.microsoft.com/fwlink/?linkid=2130430 for more information.

What it means

Thrown inside ValidateNonTphMapping when two entity types in a non-TPH hierarchy resolve to the same View StoreObjectIdentifier. Like the table clash (426) but for view mappings — each type in TPT/TPC must map to a distinct view.

Solutions

Map each type to its own view name.
Switch to TPH if a single shared view is intended.
Remove conflicting ToView calls and let mapping differ per type.

Example fix

// before
modelBuilder.UseTptMappingStrategy();
modelBuilder.Entity<Customer>().ToView("v_People");
modelBuilder.Entity<Vendor>().ToView("v_People"); // throws 427

// after
modelBuilder.Entity<Customer>().ToView("v_Customers");
modelBuilder.Entity<Vendor>().ToView("v_Vendors");

Defensive patterns

Strategy: validation

Validate before calling

foreach (var root in modelBuilder.Model.GetEntityTypes().Where(t => t.BaseType == null))
{
    var strategy = root.GetMappingStrategy();
    if (strategy != RelationalAnnotationNames.TptMappingStrategy
        && strategy != RelationalAnnotationNames.TpcMappingStrategy) continue;
    var views = new HashSet<string>();
    foreach (var et in root.GetDerivedTypesInclusive())
    {
        var so = StoreObjectIdentifier.Create(et, StoreObjectType.View);
        if (so != null && !views.Add(so.Value.Name))
            throw new InvalidOperationException($"View '{so.Value.Name}' used by multiple types in {root.DisplayName()} hierarchy.");
    }
}

Prevention

In TPT/TPC, give each type a unique ToView name.
Use TPH if a single shared view is intended.
Add a view-collision check in your model test.

When it happens

Trigger: Two types in a TPT/TPC hierarchy call ToView("SameView"), producing the same view StoreObjectIdentifier for sibling types.

Common situations: Backing a TPT/TPC hierarchy with database views and reusing a view name across types; copy-pasting ToView calls; refactor that merged view names.

Related errors

AI-assisted analysis of dotnet/efcore@3a2006ef56 (2026-08-11). Data as JSON: /api/errors/ac996f347c7b4766. Report an issue: GitHub.

Appendix: source

Thrown at src/EFCore.Relational/Infrastructure/RelationalModelValidator.cs:2245

                            entityType.DisplayName(),
                            unmappedOwnedType.FindOwnership()!.PrincipalToDependent?.Name,
                            unmappedOwnedType.DisplayName(),
                            storeObjectType));
                }

                continue;
            }

            if (derivedTypes.TryGetValue(storeObject.Value, out var otherType))
            {
                switch (storeObjectType)
                {
                    case StoreObjectType.Table:
                        throw new InvalidOperationException(
                            RelationalStrings.NonTphTableClash(
                                entityType.DisplayName(), otherType.DisplayName(), storeObject.Value.DisplayName()));
                    case StoreObjectType.View:
                        throw new InvalidOperationException(
                            RelationalStrings.NonTphViewClash(
                                entityType.DisplayName(), otherType.DisplayName(), storeObject.Value.DisplayName()));
                    case StoreObjectType.InsertStoredProcedure:
                    case StoreObjectType.DeleteStoredProcedure:
                    case StoreObjectType.UpdateStoredProcedure:
                        throw new InvalidOperationException(
                            RelationalStrings.NonTphStoredProcedureClash(
                                entityType.DisplayName(), otherType.DisplayName(), storeObject.Value.DisplayName()));
                }
            }

            if (isTpc)
            {
                var rowInternalFk = entityType.FindDeclaredReferencingRowInternalForeignKeys(storeObject.Value)
                    .FirstOrDefault();
                if (rowInternalFk != null
                    && entityType.GetDirectlyDerivedTypes().Any())
                {

View on GitHub (pinned to 3a2006ef56)