dotnet/efcore · error · InvalidOperationException

' . ' and ' . ' are both mapped to column ' ' in ' ', but…

Error message

'{entityType1}.{property1}' and '{entityType2}.{property2}' are both mapped to column '{columnName}' in '{table}', but are configured with different scales ('{scale1}' and '{scale2}').

What it means

Two properties sharing a column declare different numeric scales (the second HasPrecision argument, or HasScale). Scale is the number of digits after the decimal point; differing scales on one physical column are irreconcilable, so EF rejects the model.

Solutions

Set the same scale (second HasPrecision argument, or HasScale) on both properties.
Choose the larger scale to preserve precision across both usages.
Remap one property to a distinct column if the scales are genuinely different.

Example fix

// before
modelBuilder.Entity<Order>().Property(o => o.Total).HasPrecision(18, 2);
modelBuilder.Entity<OrderDiscount>().Property(d => d.Total).HasPrecision(18, 4); // shared column

// after
modelBuilder.Entity<Order>().Property(o => o.Total).HasPrecision(18, 4);
modelBuilder.Entity<OrderDiscount>().Property(d => d.Total).HasPrecision(18, 4);

Defensive patterns

Strategy: validation

Validate before calling

foreach (var (col, props) in sharedColumnGroups)
{
    var scales = props.Select(p => p.GetScale(storeObject)).Distinct().ToList();
    if (scales.Count > 1)
        Console.WriteLine($"Column {col} has conflicting scales: {string.Join(", ", scales)}");
}

Try / catch

try { _ = db.Model; } catch (InvalidOperationException ex) when (ex.Message.Contains("different scales")) { // align the scale argument of HasPrecision on both properties }

Prevention

Always set precision and scale together via HasPrecision(p, s) and reuse the same call.
Use named constants for currency vs percentage scales.
Smoke-test the model at startup.

When it happens

Trigger: ValidateCompatible() compares property.GetScale(storeObject) vs duplicateProperty.GetScale(storeObject) for a duplicate column and they differ.

Common situations: A rate column shared between owner and owned entity where one was configured for 4 decimal places and the other for 2; currency vs percentage fields that ended up mapped to the same column after refactoring.

Related errors

AI-assisted analysis of dotnet/efcore@3a2006ef56 (2026-08-11). Data as JSON: /api/errors/2f94262d4e34b1bb. Report an issue: GitHub.

Appendix: source

Thrown at src/EFCore.Relational/Infrastructure/RelationalModelValidator.cs:1606

        if (currentPrecision != previousPrecision)
        {
            throw new InvalidOperationException(
                RelationalStrings.DuplicateColumnNamePrecisionMismatch(
                    duplicateProperty.DeclaringType.DisplayName(),
                    duplicateProperty.Name,
                    property.DeclaringType.DisplayName(),
                    property.Name,
                    columnName,
                    storeObject.DisplayName(),
                    currentPrecision,
                    previousPrecision));
        }

        var currentScale = property.GetScale(storeObject);
        var previousScale = duplicateProperty.GetScale(storeObject);
        if (currentScale != previousScale)
        {
            throw new InvalidOperationException(
                RelationalStrings.DuplicateColumnNameScaleMismatch(
                    duplicateProperty.DeclaringType.DisplayName(),
                    duplicateProperty.Name,
                    property.DeclaringType.DisplayName(),
                    property.Name,
                    columnName,
                    storeObject.DisplayName(),
                    currentScale,
                    previousScale));
        }

        if (property.IsConcurrencyToken != duplicateProperty.IsConcurrencyToken)
        {
            throw new InvalidOperationException(
                RelationalStrings.DuplicateColumnNameConcurrencyTokenMismatch(
                    duplicateProperty.DeclaringType.DisplayName(),
                    duplicateProperty.Name,
                    property.DeclaringType.DisplayName(),

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