dotnet/efcore · error · InvalidOperationException

Unable to find a store type mapping for column '{table}.{col

Error message

Unable to find a store type mapping for column '{table}.{column}' with CLR type '{clrType}'.

What it means

Thrown by MigrationsSqlGenerator.GetColumnType when neither the relational model's column store type nor Dependencies.TypeMappingSource.FindMapping can resolve a store type for the column's CLR type and facets. EF first tries to reuse the model column's StoreType, then falls back to the TypeMappingSource; if both return null it cannot emit a column type and throws InvalidOperationException.

Source

Thrown at src/EFCore.Relational/Migrations/MigrationsSqlGenerator.cs:1451

        var storeType = Dependencies.TypeMappingSource.FindMapping(
                operation.ClrType,
                null,
                keyOrIndex,
                operation.IsUnicode,
                operation.MaxLength,
                operation.IsRowVersion,
                operation.IsFixedLength,
                operation.Precision,
                operation.Scale)
            ?.StoreType;

        if (storeType != null)
        {
            return storeType;
        }

        var fullTableName = schema != null ? $"{schema}.{tableName}" : tableName;
        throw new InvalidOperationException(
            RelationalStrings.UnsupportedTypeForColumn(fullTableName, name, operation.ClrType?.Name ?? "unknown"));
    }

    /// <summary>
    ///     Generates a SQL fragment for the default constraint of a column.
    /// </summary>
    /// <param name="defaultValue">The default value for the column.</param>
    /// <param name="defaultValueSql">The SQL expression to use for the column's default constraint.</param>
    /// <param name="columnType">Store/database type of the column.</param>
    /// <param name="builder">The command builder to use to add the SQL fragment.</param>
    protected virtual void DefaultValue(
        object? defaultValue,
        string? defaultValueSql,
        string? columnType,
        MigrationCommandListBuilder builder)
    {
        if (defaultValueSql != null)
        {

View on GitHub (pinned to dbf9771522)

Solutions

1. Register a type mapping or conversion for the CLR type (e.g. modelBuilder.Entity<T>().Property(x => x.MyEnum).HasConversion<int>() or .HasColumnType("jsonb")).
2. Install the missing provider plugin package that maps the type (e.g. NodaTime, NetTopologySuite for SQL Server/PostgreSQL).
3. Explicitly set operation.ColumnType (and the [Column(TypeName=...)] / HasColumnType) so GetColumnType short-circuits before reaching the mapping source.
4. If the CLR type is genuinely unsupported, change the property to a supported type or store it as a converted primitive (string/JSON).

Example fix

// before - custom enum type has no mapping
public class Order { public OrderStatus Status { get; set; } } // OrderStatus is a custom enum

// after - explicit conversion + column type
modelBuilder.Entity<Order>()
    .Property(o => o.Status)
    .HasConversion<int>()
    .HasColumnType("int");

foreach (var et in dbContext.Model.GetEntityTypes())
foreach (var p in et.GetProperties())
{
    var storeType = p.GetColumnType();
    if (string.IsNullOrEmpty(storeType) && p.ClrType.IsEnum && !p.GetJsonValueConverter()?.GetType().IsValueType)
        Console.WriteLine($"{et}.{p.Name} ({p.ClrType}) has no store type mapping; add HasConversion/HasColumnType.");
}

When it happens

Trigger: A column operation whose ClrType is a type the provider's type mapper does not know about (e.g. a custom struct/enum or an object/unknown type); a migration column where operation.ClrType is null (reported as 'unknown'); using a value type with no registered RelationalTypeMapping.

Common situations: Adding a property of an unmapped CLR type (e.g. a custom enum without HasConversion, a third-party type like NodaTime without the provider plugin); stripping ClrType in a hand-edited migration; provider plugin missing (e.g. NodaTime, NetTopologySuite) so its types are unmapped; a column operation built programmatically without setting ColumnType.

Related errors

• The provider '{provider}' is not a Relational provider and t
• The current migration SQL generator '{sqlGeneratorType}' is
• No DbContext named '{name}' was found.
• Unable to find provider assembly '{assemblyName}'. Ensure th
• Unable to find expected assembly attribute [DesignTimeProvid

AI-assisted analysis of dotnet/efcore@dbf9771522 (2026-08-06). Data as JSON: /api/errors/9912354da4199ae2. Report an issue: GitHub.