Class Poco::Data::AbstractExtraction

Library: Data
Package: DataCore
Header: Poco/Data/AbstractExtraction.h

Description

AbstractExtraction is the interface class that connects output positions to concrete values retrieved via an AbstractExtractor.

Inheritance

Direct Base Classes: Poco::RefCountedObject

All Base Classes: Poco::RefCountedObject

Known Derived Classes: Extraction

Member Summary

Member Functions: createPrepareObject, extract, getExtractor, getLimit, numOfColumnsHandled, numOfRowsAllowed, numOfRowsHandled, reset, setExtractor, setLimit

Inherited Functions: duplicate, referenceCount, release

Constructors

AbstractExtraction

AbstractExtraction(
Poco::UInt32 limit = Limit::LIMIT_UNLIMITED
);

Creates the AbstractExtraction. A limit value equal to EXTRACT_UNLIMITED (0xffffffffu) means that we extract as much data as possible during one execute. Otherwise the limit value is used to partition data extracting to a limited amount of rows.

Destructor

~AbstractExtraction

virtual ~AbstractExtraction();

Destroys the AbstractExtraction.

Member Functions

createPrepareObject

virtual AbstractPrepare * createPrepareObject(
AbstractPreparation * pPrep,
std::size_t pos
) const = 0;

Creates a Prepare object for the etxracting object

extract

virtual void extract(
std::size_t pos
) = 0;

Extracts a value from the param, starting at the given column position.

getExtractor

AbstractExtractor * getExtractor() const;

Retrieves the extractor object

getLimit

Poco::UInt32 getLimit() const;

Gets the limit.

numOfColumnsHandled

virtual std::size_t numOfColumnsHandled() const = 0;

Returns the number of columns that the extraction handles.

The trivial case will be one single column but when complex types are used this value can be larger than one.

numOfRowsAllowed

virtual std::size_t numOfRowsAllowed() const = 0;

Returns the upper limit on number of rows that the extraction will handle.

numOfRowsHandled

virtual std::size_t numOfRowsHandled() const = 0;

Returns the number of rows that the extraction handles.

The trivial case will be one single row but for collection data types (ie vector) it can be larger.

reset

virtual void reset() = 0;

Resets the etxractor so that it can be re-used.

setExtractor

void setExtractor(
AbstractExtractor * pExtractor
);

Sets the class used for extracting the data. Does not take ownership of the pointer.

setLimit

void setLimit(
Poco::UInt32 limit
);