class QgsVectorDataProvider : QgsDataProvider
{
%TypeHeaderCode
#include <qgsvectordataprovider.h>
%End
public:
// If you add to this, please also add to capabilitiesString()
/**
* enumeration with capabilities that providers might implement
*/
enum Capability
{
NoCapabilities = 0,
AddFeatures = 1,
DeleteFeatures = 2,
ChangeAttributeValues = 4,
AddAttributes = 8,
DeleteAttributes = 16,
SaveAsShapefile = 32,
CreateSpatialIndex = 64,
SelectAtId = 128,
ChangeGeometries = 256,
SelectGeometryAtId = 512,
RandomSelectGeometryAtId = 1024,
SequentialSelectGeometryAtId = 2048
};
/**
* Constructor of the vector provider
* @param uri uniform resource locator (URI) for a dataset
*/
QgsVectorDataProvider(QString uri = QString());
/**
* Destructor
*/
virtual ~QgsVectorDataProvider();
/**
* Returns the permanent storage type for this layer as a friendly name.
*/
virtual QString storageType() const;
/** Select features based on a bounding rectangle. Features can be retrieved with calls to getNextFeature.
* @param fetchAttributes list of attributes which should be fetched
* @param rect spatial filter
* @param fetchGeometry true if the feature geometry should be fetched
* @param useIntersect true if an accurate intersection test should be used,
* false if a test based on bounding box is sufficient
*/
virtual void select(QList<int> fetchAttributes = QList<int>(),
QgsRect rect = QgsRect(),
bool fetchGeometry = true,
bool useIntersect = false) = 0;
/**
* Update the feature count based on current spatial filter. If not
* overridden in the data provider this function returns -1
*/
virtual long updateFeatureCount();
/**
* Gets the feature at the given feature ID.
* @param featureId id of the feature
* @param feature feature which will receive the data
* @param fetchGeoemtry if true, geometry will be fetched from the provider
* @param fetchAttributes a list containing the indexes of the attribute fields to copy
* @return True when feature was found, otherwise false
*/
virtual bool getFeatureAtId(int featureId,
QgsFeature& feature,
bool fetchGeometry = true,
QList<int> fetchAttributes = QList<int>());
/**
* Get the next feature resulting from a select operation.
* @param feature feature which will receive data from the provider
* @return true when there was a feature to fetch, false when end was hit
*/
virtual bool getNextFeature(QgsFeature& feature) = 0;
/**
* Get feature type.
* @return int representing the feature type
*/
virtual QGis::WKBTYPE geometryType() const = 0;
/**
* Number of features in the layer
* @return long containing number of features
*/
virtual long featureCount() const = 0;
/**
* Number of attribute fields for a feature in the layer
*/
virtual uint fieldCount() const = 0;
/**
* Return a map of indexes with field names for this layer
* @return map of fields
*/
virtual const QMap<int, QgsField> & fields() const = 0;
/**
* Return a short comment for the data that this provider is
* providing access to (e.g. the comment for postgres table).
*/
virtual QString dataComment() const;
/** Restart reading features from previous select operation */
virtual void reset() = 0;
/**
* Returns the minimum value of an attributs
* @param index the index of the attribute
*
* Default implementation walks all numeric attributes and caches minimal
* and maximal values. If provider has facilities to retreive minimal
* value directly, override this function.
*/
virtual QVariant minValue(int index);
/**
* Returns the maximum value of an attributs
* @param index the index of the attribute
*
* Default implementation walks all numeric attributes and caches minimal
* and maximal values. If provider has facilities to retreive maximal
* value directly, override this function.
*/
virtual QVariant maxValue(int index);
/**
* Adds a list of features
* @return true in case of success and false in case of failure
*/
virtual bool addFeatures(QList<QgsFeature> & flist);
/**
* Deletes a feature
* @param id list containing feature ids to delete
* @return true in case of success and false in case of failure
*/
virtual bool deleteFeatures(const QSet<int> & id);
/**
* Adds new attributes
* @param attributes map with attribute name as key and type as value
* @return true in case of success and false in case of failure
*/
virtual bool addAttributes(const QMap<QString, QString> & attributes);
/**
* Deletes existing attributes
* @param attributes a set containing indexes of attributes
* @return true in case of success and false in case of failure
*/
virtual bool deleteAttributes(const QSet<int> & attributes);
/**
* Changes attribute values of existing features.
* @param attr_map a map containing changed attributes
* @return true in case of success and false in case of failure
*/
virtual bool changeAttributeValues(const QMap<int, QMap<int, QVariant> > & attr_map);
/**
* Returns the default value for field specified by @c fieldId
*/
virtual QVariant getDefaultValue(int fieldId);
/**
* Changes geometries of existing features
* @param geometry_map A std::map containing the feature IDs to change the geometries of.
* the second map parameter being the new geometries themselves
* @return true in case of success and false in case of failure
*/
virtual bool changeGeometryValues(QMap<int, QgsGeometry> & geometry_map);
/**
* Creates a spatial index on the datasource (if supported by the provider type).
* @return true in case of success
*/
virtual bool createSpatialIndex();
/** Returns a bitmask containing the supported capabilities
Note, some capabilities may change depending on whether
a spatial filter is active on this provider, so it may
be prudent to check this value per intended operation.
*/
virtual int capabilities() const;
/**
* Returns the above in friendly format.
*/
QString capabilitiesString() const;
/**
* Set encoding used for accessing data from layer
*/
virtual void setEncoding(const QString& e);
/**
* Get encoding which is used for accessing data
*/
QString encoding() const;
/**
* Returns the index of a field name or -1 if the field does not exist
*/
int indexFromFieldName(const QString& fieldName) const;
/**
* Return list of indexes to fetch all attributes in getNextFeature()
*/
QList<int> allAttributesList();
/**Returns the names of the numerical types*/
const QSet<QString>& supportedNativeTypes() const;
/**
* Set whether provider should return also features that don't have
* associated geometry. FALSE by default
*/
void setFetchFeaturesWithoutGeom(bool fetch);
};