Method getColumnType

src/Interpreters/InterpreterCreateQuery.cpp:537–577

}

DataTypePtr InterpreterCreateQuery::getColumnType(
    const ASTColumnDeclaration & col_decl, const LoadingStrictnessLevel mode, const bool make_columns_nullable)
{
    auto col_type = col_decl.getType();
    if (!col_type)
    {
        /// we're creating dummy DataTypeUInt8 in order to prevent the NullPointerException in ExpressionActions
        return std::make_shared<DataTypeUInt8>();
    }

    DataTypePtr column_type = DataTypeFactory::instance().get(col_type);

    if (LoadingStrictnessLevel::ATTACH <= mode)
        setVersionToAggregateFunctions(column_type, true);

    if (col_decl.null_modifier)
    {
        if (column_type->isNullable())
            throw Exception(ErrorCodes::ILLEGAL_SYNTAX_FOR_DATA_TYPE, "Can't use [NOT] NULL modifier with Nullable type");
        if (*col_decl.null_modifier)
            column_type = makeNullable(column_type);
    }
    else if (make_columns_nullable)
    {
        column_type = makeNullable(column_type);
    }
    else if (auto default_expr = col_decl.getDefaultExpression();
        !hasNullable(column_type) && col_decl.default_specifier == ColumnDefaultSpecifier::Default && default_expr
        && default_expr->as<ASTLiteral>() && default_expr->as<ASTLiteral>()->value.isNull())
    {
        if (column_type->lowCardinality())
        {
            const auto * low_cardinality_type = typeid_cast<const DataTypeLowCardinality *>(column_type.get());
            chassert(low_cardinality_type);
            column_type = std::make_shared<DataTypeLowCardinality>(makeNullable(low_cardinality_type->getDictionaryType()));
        }
        else
            column_type = makeNullable(column_type);
    }
    return column_type;
}

ColumnsDescription InterpreterCreateQuery::getColumnsDescription(
    const ASTExpressionList & columns_ast, ContextPtr context_, LoadingStrictnessLevel mode, bool is_restore_from_backup)