Function checkKeyExpression

src/Storages/MergeTree/MergeTreeData.cpp:906–933

}

static void checkKeyExpression(const ExpressionActions & expr, const Block & sample_block, const String & key_name, bool allow_nullable_key)
{
    if (expr.hasArrayJoin())
        throw Exception(ErrorCodes::ILLEGAL_COLUMN, "{} key cannot contain array joins", key_name);

    try
    {
        expr.assertDeterministic();
    }
    catch (Exception & e)
    {
        e.addMessage(fmt::format("for {} key", key_name));
        throw;
    }

    for (const ColumnWithTypeAndName & element : sample_block)
    {
        const ColumnPtr & column = element.column;
        if (column && (isColumnConst(*column) || column->isDummy()))
            throw Exception(ErrorCodes::ILLEGAL_COLUMN, "{} key cannot contain constants", key_name);

        if (!allow_nullable_key && hasNullable(element.type))
            throw Exception(
                            ErrorCodes::ILLEGAL_COLUMN,
                            "{} key contains nullable columns, "
                            "but merge tree setting `allow_nullable_key` is disabled", key_name);
    }
}

void MergeTreeData::checkProperties(
    const StorageInMemoryMetadata & new_metadata,