dotnet/efcore · error · InvalidOperationException

The number of key values ({valuesCount}) doesn't match the n

Error message

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

What it means

Thrown inside GenerateModificationCommands(DeleteDataOperation, ...) in src/EFCore.Relational/Migrations/MigrationsSqlGenerator.cs:969 (message key DeleteDataOperationValuesCountMismatch). It compares operation.KeyColumns.Length against operation.KeyValues.GetLength(1) and throws InvalidOperationException when they differ. DeleteData builds a WHERE clause per row from the key columns, so the per-row key-value count must equal the key-column count.

Source

Thrown at src/EFCore.Relational/Migrations/MigrationsSqlGenerator.cs:969

        }

        builder.Append(sqlBuilder.ToString());
        EndStatement(builder);
    }

    /// <summary>
    ///     Generates the commands that correspond to the given operation.
    /// </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)));

View on GitHub (pinned to dbf9771522)

Solutions

Ensure every row in keyValues has exactly operation.KeyColumns.Length entries (the second dimension of the 2D array equals the keyColumns array length).
Re-scaffold the migration so DeleteData arrays are regenerated for the current composite key.
Use modelBuilder.Entity<T>().HasData(...) and remove rows there, letting EF scaffold the DeleteData consistently.
Audit: assert keyValues.GetLength(1) == keyColumns.Length for each DeleteData.

Example fix

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

// after (one value per key column):
migrationBuilder.DeleteData(
    table: "Members",
    keyColumns: new[] { "UserId", "GroupId" },
    keyValues: new object[,] { { 7, 3 } });

Defensive patterns

Strategy: validation

Validate before calling

static bool DeleteDataKeyShapeIsValid(string[] keyColumns, object[,] keyValues)
{
    return keyValues.GetLength(1) == keyColumns.Length;
}

// usage before calling migrationBuilder.DeleteData
if (!DeleteDataKeyShapeIsValid(keyColumns, keyValues))
    throw new InvalidOperationException("keyValues second dimension must equal keyColumns.Length");

Try / catch

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

Prevention

Prefer HasData management so EF scaffolds DeleteData with correct composite-key arrays.
When editing DeleteData for composite keys, update keyColumns and every keyValues row together.
Add a test asserting keyValues.GetLength(1) == keyColumns.Length for each DeleteData.
Re-scaffold migrations after key changes rather than hand-editing.

When it happens

Trigger: A migration calls migrationBuilder.DeleteData(keyColumns: new[] { "Id", "TenantId" }, keyValues: new object[,] { { 1 } }) where the inner dimension of keyValues does not match the keyColumns length. Happens after editing a generated migration (e.g. composite key) and dropping a key value, or scaffolding HasData removal for a composite-key entity incorrectly.

Common situations: Editing generated DeleteData calls for composite-key tables and miscounting. Removing a HasData seed row for a composite-key entity and then hand-editing the migration. Copy-paste errors in hand-authored migrations.

Related errors

AI-assisted analysis of dotnet/efcore@dbf9771522 (2026-08-06). Data as JSON: /api/errors/ed25476e25319e00. Report an issue: GitHub.