dotnet/efcore · error · InvalidOperationException

The number of key column types ({typesCount}) doesn't match

Error message

The number of key column types ({typesCount}) doesn't match the number of key columns ({columnsCount}) for the data deletion operation on '{table}'. Provide the same number of key column types and key columns.

What it means

Thrown inside GenerateModificationCommands(DeleteDataOperation, ...) in src/EFCore.Relational/Migrations/MigrationsSqlGenerator.cs:977 (message key DeleteDataOperationTypesCountMismatch). It throws InvalidOperationException when operation.KeyColumnTypes is non-null but its length differs from operation.KeyColumns.Length. KeyColumnTypes is an optional explicit type override; if supplied, it must align element-for-element with KeyColumns.

Source

Thrown at src/EFCore.Relational/Migrations/MigrationsSqlGenerator.cs:977

    /// </summary>
    /// <param name="operation">The data operation to generate commands for.</param>
    /// <param name="model">The model.</param>
    /// <returns>The commands that correspond to the given operation.</returns>
    protected virtual IEnumerable<IReadOnlyModificationCommand> GenerateModificationCommands(
        DeleteDataOperation operation,
        IModel? model)
    {
        if (operation.KeyColumns.Length != operation.KeyValues.GetLength(1))
        {
            throw new InvalidOperationException(
                RelationalStrings.DeleteDataOperationValuesCountMismatch(
                    operation.KeyValues.GetLength(1), operation.KeyColumns.Length, FormatTable(operation.Table, operation.Schema)));
        }

        if (operation.KeyColumnTypes != null
            && operation.KeyColumns.Length != operation.KeyColumnTypes.Length)
        {
            throw new InvalidOperationException(
                RelationalStrings.DeleteDataOperationTypesCountMismatch(
                    operation.KeyColumnTypes.Length, operation.KeyColumns.Length, FormatTable(operation.Table, operation.Schema)));
        }

        if (operation.KeyColumnTypes == null
            && model == null)
        {
            throw new InvalidOperationException(
                RelationalStrings.DeleteDataOperationNoModel(
                    FormatTable(operation.Table, operation.Schema)));
        }

        var keyPropertyMappings = operation.KeyColumnTypes == null
            ? GetPropertyMappings(operation.KeyColumns, operation.Table, operation.Schema, model)
            : null;

        for (var i = 0; i < operation.KeyValues.GetLength(0); i++)
        {

View on GitHub (pinned to dbf9771522)

Solutions

1. Make operation.KeyColumnTypes either null (types resolved from the model) or an array of exactly operation.KeyColumns.Length.
2. Re-scaffold the migration to regenerate consistent keyColumnTypes.
3. Map the table to an entity type so keyColumnTypes can be omitted entirely.
4. Audit: for every i, KeyColumns[i] must pair with KeyColumnTypes[i].

Example fix

// before (2 key columns, 1 key type):
migrationBuilder.DeleteData(
    table: "Members",
    keyColumns: new[] { "UserId", "GroupId" },
    keyColumnTypes: new[] { "int" },
    keyValues: new object[,] { { 7, 3 } });

// after (aligned):
migrationBuilder.DeleteData(
    table: "Members",
    keyColumns: new[] { "UserId", "GroupId" },
    keyColumnTypes: new[] { "int", "int" },
    keyValues: new object[,] { { 7, 3 } });

static bool DeleteKeyTypesAreValid(string[] keyColumns, string[]? keyColumnTypes)
{
    return keyColumnTypes == null || keyColumnTypes.Length == keyColumns.Length;
}

// usage
if (!DeleteKeyTypesAreValid(keyColumns, keyColumnTypes))
    throw new InvalidOperationException("keyColumnTypes.Length must equal keyColumns.Length (or be null)");

try
{
    await dbContext.Database.MigrateAsync();
}
catch (InvalidOperationException ex) when (ex.Message.Contains("number of key column types") && ex.Message.Contains("data deletion"))
{
    logger.LogError(ex, "A DeleteDataOperation has a keyColumnTypes/keyColumns length mismatch; fix the migration.");
    throw;
}

When it happens

Trigger: A migration calls migrationBuilder.DeleteData with keyColumnTypes: set to an array whose length differs from keyColumns:. For example keyColumns: new[] { "Id", "TenantId" } with keyColumnTypes: new[] { "int" }. Common after hand-editing a migration and removing a key column but not its type.

Common situations: Manually adding keyColumnTypes and miscounting. Editing a model-less migration and forgetting a key type entry. Refactoring a composite key without updating the type array.

Related errors

• The number of key values ({valuesCount}) doesn't match the n
• The number of values ({valuesCount}) doesn't match the numbe
• The number of column types ({typesCount}) doesn't match the
• The data deletion operation on '{table}' is not associated w
• The number of key values ({valuesCount}) doesn't match the n

AI-assisted analysis of dotnet/efcore@dbf9771522 (2026-08-06). Data as JSON: /api/errors/2470b014015e30a9. Report an issue: GitHub.