ClickHouse/dbms/src/Dictionaries/ODBCBlockInputStream.cpp

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2016-12-08 02:49:04 +00:00
#include <DB/Dictionaries/ODBCBlockInputStream.h>
#include <DB/Columns/ColumnsNumber.h>
#include <DB/Columns/ColumnString.h>
#include <ext/range.hpp>
#include <vector>
namespace DB
{
namespace ErrorCodes
{
extern const int NUMBER_OF_COLUMNS_DOESNT_MATCH;
}
ODBCBlockInputStream::ODBCBlockInputStream(
Poco::Data::Session && session, const std::string & query_str, const Block & sample_block,
const size_t max_block_size)
:
session{session},
statement{(this->session << query_str, Poco::Data::Keywords::now)},
result{statement},
iterator{result.begin()},
max_block_size{max_block_size}
{
if (sample_block.columns() != result.columnCount())
throw Exception{
"RecordSet contains " + toString(result.columnCount()) + " columns while " +
toString(sample_block.columns()) + " expected",
ErrorCodes::NUMBER_OF_COLUMNS_DOESNT_MATCH};
description.init(sample_block);
}
String ODBCBlockInputStream::getID() const
{
return "ODBC(" + statement.toString() + ")";
}
namespace
{
using ValueType = ExternalResultDescription::ValueType;
static void insertValue(IColumn * const column, const ValueType type, const Poco::Dynamic::Var & value)
{
switch (type)
{
case ValueType::UInt8: static_cast<ColumnUInt8 *>(column)->insert(value.convert<UInt64>()); break;
case ValueType::UInt16: static_cast<ColumnUInt16 *>(column)->insert(value.convert<UInt64>()); break;
case ValueType::UInt32: static_cast<ColumnUInt32 *>(column)->insert(value.convert<UInt64>()); break;
case ValueType::UInt64: static_cast<ColumnUInt64 *>(column)->insert(value.convert<UInt64>()); break;
case ValueType::Int8: static_cast<ColumnInt8 *>(column)->insert(value.convert<Int64>()); break;
case ValueType::Int16: static_cast<ColumnInt16 *>(column)->insert(value.convert<Int64>()); break;
case ValueType::Int32: static_cast<ColumnInt32 *>(column)->insert(value.convert<Int64>()); break;
case ValueType::Int64: static_cast<ColumnInt64 *>(column)->insert(value.convert<Int64>()); break;
case ValueType::Float32: static_cast<ColumnFloat32 *>(column)->insert(value.convert<Float64>()); break;
case ValueType::Float64: static_cast<ColumnFloat64 *>(column)->insert(value.convert<Float64>()); break;
case ValueType::String: static_cast<ColumnString *>(column)->insert(value.convert<String>()); break;
case ValueType::Date: static_cast<ColumnUInt16 *>(column)->insert(UInt16{LocalDate{value.convert<String>()}.getDayNum()}); break;
case ValueType::DateTime: static_cast<ColumnUInt32 *>(column)->insert(time_t{LocalDateTime{value.convert<String>()}}); break;
}
}
}
Block ODBCBlockInputStream::readImpl()
{
if (iterator == result.end())
return {};
auto block = description.sample_block.cloneEmpty();
/// cache pointers returned by the calls to getByPosition
std::vector<IColumn *> columns(block.columns());
for (const auto i : ext::range(0, columns.size()))
columns[i] = block.getByPosition(i).column.get();
size_t num_rows = 0;
while (iterator != result.end())
{
Poco::Data::Row & row = *iterator;
for (const auto idx : ext::range(0, row.fieldCount()))
{
const Poco::Dynamic::Var & value = row[idx];
if (!value.isEmpty())
insertValue(columns[idx], description.types[idx], value);
else
insertDefaultValue(columns[idx], *description.sample_columns[idx]);
}
++num_rows;
if (num_rows == max_block_size)
break;
++iterator;
}
return block;
}
}