This is the base class for vector data providers. More...

#include <qgsvectordataprovider.h>

Inheritance diagram for QgsVectorDataProvider:

Classes
struct	NativeType

Public Types
enum	Capability { NoCapabilities = 0, AddFeatures = 1, DeleteFeatures = 1 << 1, ChangeAttributeValues = 1 << 2, AddAttributes = 1 << 3, DeleteAttributes = 1 << 4, SaveAsShapefile = 1 << 5, CreateSpatialIndex = 1 << 6, SelectAtId = 1 << 7, ChangeGeometries = 1 << 8, SelectGeometryAtId = 1 << 9, RandomSelectGeometryAtId = 1 << 10, SequentialSelectGeometryAtId = 1 << 11, CreateAttributeIndex = 1 << 12, SelectEncoding = 1 << 13, SimplifyGeometries = 1 << 14, SimplifyGeometriesWithTopologicalValidation = 1 << 15, TransactionSupport = 1 << 16, CircularGeometries = 1 << 17, ChangeFeatures = 1 << 18, RenameAttributes = 1 << 19 }
	enumeration with capabilities that providers might implement More...

Public Types inherited from QgsDataProvider
enum	DataCapability { NoDataCapabilities = 0, File = 1, Dir = 1 << 1, Database = 1 << 2, Net = 1 << 3 }

enum	ProviderProperty { EvaluateDefaultValues, CustomData = 3000 }
	Properties are used to pass custom configuration options into data providers. More...

Signals
void	raiseError (const QString &msg)
	Signals an error in this provider. More...

Signals inherited from QgsDataProvider
void	dataChanged ()
	This is emitted whenever an asynchronous operation has finished and the data should be redrawn. More...

void	dataChanged (int changed)
	This is emitted whenever data or metadata (e.g. More...

void	fullExtentCalculated ()
	This is emitted whenever the worker thread has fully calculated the PostGIS extents for this layer, and its event has been received by this provider. More...

Public Member Functions
	QgsVectorDataProvider (const QString &uri=QString())
	Constructor of the vector provider. More...

virtual	~QgsVectorDataProvider ()
	Destructor. More...

virtual bool	addAttributes (const QList< QgsField > &attributes)
	Adds new attributes. More...

virtual bool	addFeatures (QgsFeatureList &flist)
	Adds a list of features. More...

virtual QVariant	aggregate (QgsAggregateCalculator::Aggregate aggregate, int index, const QgsAggregateCalculator::AggregateParameters &parameters, QgsExpressionContext *context, bool &ok)
	Calculates an aggregated value from the layer's features. More...

virtual QgsAttributeList	attributeIndexes ()
	Return list of indexes to fetch all attributes in nextFeature() More...

virtual int	capabilities () const
	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. More...

QString	capabilitiesString () const
	Returns the above in friendly format. More...

virtual bool	changeAttributeValues (const QgsChangedAttributesMap &attr_map)
	Changes attribute values of existing features. More...

virtual bool	changeFeatures (const QgsChangedAttributesMap &attr_map, const QgsGeometryMap &geometry_map)
	Changes attribute values and geometries of existing features. More...

virtual bool	changeGeometryValues (const QgsGeometryMap &geometry_map)
	Changes geometries of existing features. More...

void	clearErrors ()
	Clear recorded errors. More...

virtual bool	createAttributeIndex (int field)
	Create an attribute index on the datasource. More...

virtual bool	createSpatialIndex ()
	Creates a spatial index on the datasource (if supported by the provider type). More...

virtual QString	dataComment () const
	Return a short comment for the data that this provider is providing access to (e.g. More...

virtual QVariant	defaultValue (int fieldId, bool forceLazyEval=false)
	Returns the default value for field specified by fieldId. More...

virtual bool	deleteAttributes (const QgsAttributeIds &attributes)
	Deletes existing attributes. More...

virtual bool	deleteFeatures (const QgsFeatureIds &id)
	Deletes one or more features. More...

virtual bool	doesStrictFeatureTypeCheck () const
	Returns true if the provider is strict about the type of inserted features (e.g. More...

QString	encoding () const
	Get encoding which is used for accessing data. More...

virtual void	enumValues (int index, QStringList &enumList)
	Returns the possible enum values of an attribute. More...

QStringList	errors ()
	Get recorded errors. More...

virtual long	featureCount () const =0
	Number of features in the layer. More...

virtual QgsAbstractFeatureSource *	featureSource () const =0
	Return feature source object that can be used for querying provider's data. More...

int	fieldNameIndex (const QString &fieldName) const
	Returns the index of a field name or -1 if the field does not exist. More...

QMap< QString, int >	fieldNameMap () const
	Return a map where the key is the name of the field and the value is its index. More...

virtual const QgsFields &	fields () const =0
	Return a map of indexes with field names for this layer. More...

virtual void	forceReload ()
	Forces a reload of the underlying datasource if the provider implements this method. More...

virtual QGis::WkbType	geometryType () const =0
	Get feature type. More...

virtual QgsFeatureIterator	getFeatures (const QgsFeatureRequest &request=QgsFeatureRequest())=0
	Query the provider for features specified in request. More...

bool	hasErrors ()
	Provider has errors to report. More...

virtual bool	isSaveAndLoadStyleToDBSupported ()
	It returns false by default. More...

virtual QSet< QString >	layerDependencies () const
	Get the list of layer ids on which this layer depends. More...

virtual QVariant	maximumValue (int index)
	Returns the maximum value of an attribute. More...

virtual QVariant	minimumValue (int index)
	Returns the minimum value of an attribute. More...

const QList< NativeType > &	nativeTypes () const
	Returns the names of the supported types. More...

virtual QgsAttrPalIndexNameHash	palAttributeIndexNames () const
	Return list of indexes to names for QgsPalLabeling fix. More...

virtual QgsAttributeList	pkAttributeIndexes ()
	Return list of indexes of fields that make up the primary key. More...

virtual bool	renameAttributes (const QgsFieldNameMap &renamedAttributes)
	Renames existing attributes. More...

virtual void	setEncoding (const QString &e)
	Set encoding used for accessing data from layer. More...

virtual QString	storageType () const
	Returns the permanent storage type for this layer as a friendly name. More...

bool	supportedType (const QgsField &field) const
	check if provider supports type of field More...

virtual QgsTransaction *	transaction () const
	Returns the transaction this data provider is included in, if any. More...

virtual void	uniqueValues (int index, QList< QVariant > &uniqueValues, int limit=-1)
	Return unique values of an attribute. More...

Public Member Functions inherited from QgsDataProvider
	QgsDataProvider (QString const &uri="")

virtual	~QgsDataProvider ()
	We need this so the subclass destructors get called. More...

virtual QgsCoordinateReferenceSystem	crs ()=0
	Get the QgsCoordinateReferenceSystem for this layer. More...

virtual QString	dataSourceUri (bool expandAuthConfig=false) const
	Get the data source specification. More...

virtual QDateTime	dataTimestamp () const
	Current time stamp of data source. More...

virtual QString	description () const =0
	Return description. More...

virtual bool	enterUpdateMode ()
	Enter update mode. More...

virtual QgsError	error () const
	Get current status error. More...

virtual QgsRectangle	extent ()=0
	Get the extent of the layer. More...

virtual QString	fileRasterFilters () const
	Return raster file filter string. More...

virtual QString	fileVectorFilters () const
	Return vector file filter string. More...

virtual void	invalidateConnections (const QString &connection)
	Invalidate connections corresponding to specified name. More...

virtual bool	isValid ()=0
	Returns true if this is a valid layer. More...

virtual bool	leaveUpdateMode ()
	Leave update mode. More...

virtual QString	name () const =0
	Return a provider name. More...

QVariant	providerProperty (ProviderProperty property, const QVariant &defaultValue=QVariant()) const
	Get the current value of a certain provider property. More...

QVariant	providerProperty (int property, const QVariant &defaultValue) const
	Get the current value of a certain provider property. More...

virtual void	reloadData ()
	Reloads the data from the source. More...

virtual void	setDataSourceUri (const QString &uri)
	Set the data source specification. More...

virtual void	setLayerOrder (const QStringList &layers)
	Reorder the list of layer names to be rendered by this provider (in order from bottom to top) More...

void	setProviderProperty (ProviderProperty property, const QVariant &value)
	Allows setting arbitrary properties on the provider. More...

void	setProviderProperty (int property, const QVariant &value)
	Allows setting arbitrary properties on the provider. More...

virtual void	setSubLayerVisibility (const QString &name, bool vis)
	Set the visibility of the given sublayer name. More...

virtual bool	setSubsetString (const QString &subset, bool updateFeatureCount=true)
	Set the subset string used to create a subset of features in the layer. More...

virtual uint	subLayerCount () const
	return the number of layers for the current data source More...

virtual QStringList	subLayers () const
	Sub-layers handled by this provider, in order from bottom to top. More...

virtual QStringList	subLayerStyles () const
	Sub-layer styles for each sub-layer handled by this provider, in order from bottom to top. More...

virtual QString	subsetString ()
	Returns the subset definition string (typically sql) currently in use by the layer and used by the provider to limit the feature set. More...

virtual bool	supportsSubsetString ()
	Provider supports setting of subset strings. More...

virtual QDateTime	timestamp () const
	Time stamp of data source in the moment when data/metadata were loaded by provider. More...

virtual void	updateExtents ()
	Update the extents of the layer. More...

Public Member Functions inherited from QObject
	QObject (QObject *parent)

	QObject (QObject parent, const char name)

virtual	~QObject ()

bool	blockSignals (bool block)

QObject *	child (const char objName, const char inheritsClass, bool recursiveSearch) const

const QObjectList &	children () const

const char *	className () const

bool	connect (const QObject sender, const char signal, const char *method, Qt::ConnectionType type) const

void	deleteLater ()

void	destroyed (QObject *obj)

bool	disconnect (const QObject receiver, const char method)

bool	disconnect (const char signal, const QObject receiver, const char *method)

void	dumpObjectInfo ()

void	dumpObjectTree ()

QList< QByteArray >	dynamicPropertyNames () const

virtual bool	event (QEvent *e)

virtual bool	eventFilter (QObject watched, QEvent event)

T	findChild (const QString &name) const

QList< T >	findChildren (const QRegExp &regExp) const

QList< T >	findChildren (const QString &name) const

bool	inherits (const char *className) const

void	insertChild (QObject *object)

void	installEventFilter (QObject *filterObj)

bool	isA (const char *className) const

bool	isWidgetType () const

void	killTimer (int id)

virtual const QMetaObject *	metaObject () const

void	moveToThread (QThread *targetThread)

const char *	name () const

const char *	name (const char *defaultName) const

QString	objectName () const

QObject *	parent () const

QVariant	property (const char *name) const

void	removeChild (QObject *object)

void	removeEventFilter (QObject *obj)

void	setName (const char *name)

void	setObjectName (const QString &name)

void	setParent (QObject *parent)

bool	setProperty (const char *name, const QVariant &value)

bool	signalsBlocked () const

int	startTimer (int interval)

QThread *	thread () const

Static Public Member Functions
static const QStringList &	availableEncodings ()
	Returns a list of available encodings. More...

static QVariant	convertValue (QVariant::Type type, const QString &value)

Static Public Member Functions inherited from QObject
bool	connect (const QObject sender, const char signal, const QObject receiver, const char method, Qt::ConnectionType type)

bool	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type)

bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char method)

bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method)

QString	tr (const char sourceText, const char disambiguation, int n)

QString	trUtf8 (const char sourceText, const char disambiguation, int n)

Static Public Attributes
static const int	EditingCapabilities
	Bitmask of all provider's editing capabilities. More...

Protected Member Functions
void	clearMinMaxCache ()

QgsGeometry *	convertToProviderType (const QgsGeometry *geom) const
	Converts the geometry to the provider type if possible / necessary this is the list of possible modifications: More...

void	fillMinMaxCache ()

void	pushError (const QString &msg)

Protected Member Functions inherited from QgsDataProvider
void	appendError (const QgsErrorMessage &theMessage)
	Add error message. More...

void	setError (const QgsError &theError)
	Set error message. More...

Protected Member Functions inherited from QObject
bool	checkConnectArgs (const char signal, const QObject object, const char *method)

virtual void	childEvent (QChildEvent *event)

virtual void	connectNotify (const char *signal)

virtual void	customEvent (QEvent *event)

virtual void	disconnectNotify (const char *signal)

int	receivers (const char *signal) const

QObject *	sender () const

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *event)

Protected Attributes
QgsAttributeList	mAttributesToFetch
	List of attribute indices to fetch with nextFeature calls. More...

QgsAttrPalIndexNameHash	mAttrPalIndexName
	Old-style mapping of index to name for QgsPalLabeling fix. More...

QMap< int, QVariant >	mCacheMaxValues

bool	mCacheMinMaxDirty

QMap< int, QVariant >	mCacheMinValues

QTextCodec *	mEncoding
	Encoding. More...

QList< NativeType >	mNativeTypes
	The names of the providers native types. More...

Protected Attributes inherited from QgsDataProvider
QgsError	mError
	Error. More...

QDateTime	mTimestamp
	Timestamp of data in the moment when the data were loaded by provider. More...

Friends
class	QgsTransaction

class	QgsVectorLayerEditBuffer

Additional Inherited Members
Static Protected Member Functions inherited from QObject
QByteArray	normalizeSignalSlot (const char *signalSlot)

Properties inherited from QObject
	objectName

Detailed Description

This is the base class for vector data providers.

Data providers abstract the retrieval and writing (where supported) of feature and attribute information from a spatial datasource.

Definition at line 50 of file qgsvectordataprovider.h.

Member Enumeration Documentation

◆ Capability

enum QgsVectorDataProvider::Capability

enumeration with capabilities that providers might implement

Enumerator
NoCapabilities	Provider has no capabilities.
AddFeatures	Allows adding features.
DeleteFeatures	Allows deletion of features.
ChangeAttributeValues	Allows modification of attribute values.
AddAttributes	Allows addition of new attributes (fields)
DeleteAttributes	Allows deletion of attributes (fields)
SaveAsShapefile	DEPRECATED - do not use.
CreateSpatialIndex	Allows creation of spatial index.
SelectAtId	Fast access to features using their ID.
ChangeGeometries	Allows modifications of geometries.
SelectGeometryAtId	DEPRECATED - do not use.
RandomSelectGeometryAtId	DEPRECATED - do not use.
SequentialSelectGeometryAtId	DEPRECATED - do not use.
CreateAttributeIndex	DEPRECATED - do not use.
SelectEncoding	Allows user to select encoding.
SimplifyGeometries	Supports simplification of geometries on provider side according to a distance tolerance.
SimplifyGeometriesWithTopologicalValidation	Supports topological simplification of geometries on provider side according to a distance tolerance.
TransactionSupport	Supports transactions.
CircularGeometries	Supports circular geometry types (circularstring, compoundcurve, curvepolygon)
ChangeFeatures	Supports joint updates for attributes and geometry Providers supporting this should still define ChangeGeometries \| ChangeAttributeValues.
RenameAttributes	Supports renaming attributes (fields). Added in QGIS 2.16

Definition at line 63 of file qgsvectordataprovider.h.

Constructor & Destructor Documentation

◆ QgsVectorDataProvider()

QgsVectorDataProvider::QgsVectorDataProvider ( const QString & uri = QString() )

Constructor of the vector provider.

Parameters

uri	uniform resource locator (URI) for a dataset

Definition at line 36 of file qgsvectordataprovider.cpp.

◆ ~QgsVectorDataProvider()

QgsVectorDataProvider::~QgsVectorDataProvider ( )

virtual

Destructor.

Definition at line 46 of file qgsvectordataprovider.cpp.

Member Function Documentation

◆ addAttributes()

bool QgsVectorDataProvider::addAttributes ( const QList< QgsField > & attributes )

virtual

Adds new attributes.

Parameters

attributes list of new attributes

Returns: true in case of success and false in case of failure

Definition at line 72 of file qgsvectordataprovider.cpp.

◆ addFeatures()

bool QgsVectorDataProvider::addFeatures ( QgsFeatureList & flist )

virtual

Adds a list of features.

Returns: true in case of success and false in case of failure

Definition at line 60 of file qgsvectordataprovider.cpp.

◆ aggregate()

QVariant QgsVectorDataProvider::aggregate	(	QgsAggregateCalculator::Aggregate	aggregate,
		int	index,
		const QgsAggregateCalculator::AggregateParameters &	parameters,
		QgsExpressionContext *	context,
		bool &	ok
	)

virtual

Calculates an aggregated value from the layer's features.

The base implementation does nothing, but subclasses can override this method to handoff calculation of aggregates to the provider.

Parameters

aggregate	aggregate to calculate
index	the index of the attribute to calculate aggregate over
parameters	parameters controlling aggregate calculation
context	expression context for filter
ok	will be set to true if calculation was successfully performed by the data provider

Returns: calculated aggregate value

Note: added in QGIS 2.16

Definition at line 415 of file qgsvectordataprovider.cpp.

◆ attributeIndexes()

QgsAttributeList QgsVectorDataProvider::attributeIndexes ( )

virtual

Return list of indexes to fetch all attributes in nextFeature()

Definition at line 282 of file qgsvectordataprovider.cpp.

◆ availableEncodings()

const QStringList & QgsVectorDataProvider::availableEncodings ( )

static

Returns a list of available encodings.

Definition at line 535 of file qgsvectordataprovider.cpp.

◆ capabilities()

int QgsVectorDataProvider::capabilities ( ) const

virtual

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.

Definition at line 128 of file qgsvectordataprovider.cpp.

◆ capabilitiesString()

QString QgsVectorDataProvider::capabilitiesString ( ) const

Returns the above in friendly format.

Definition at line 163 of file qgsvectordataprovider.cpp.

◆ changeAttributeValues()

bool QgsVectorDataProvider::changeAttributeValues ( const QgsChangedAttributesMap & attr_map )

virtual

Changes attribute values of existing features.

Parameters

attr_map a map containing changed attributes

Returns: true in case of success and false in case of failure

Definition at line 90 of file qgsvectordataprovider.cpp.

◆ changeFeatures()

bool QgsVectorDataProvider::changeFeatures	(	const QgsChangedAttributesMap &	attr_map,
		const QgsGeometryMap &	geometry_map
	)

virtual

Changes attribute values and geometries of existing features.

Parameters

attr_map	a map containing changed attributes
geometry_map	A QgsGeometryMap whose index contains the feature IDs that will have their geometries changed. The second map parameter being the new geometries themselves

Returns: true in case of success and false in case of failure

Definition at line 109 of file qgsvectordataprovider.cpp.

◆ changeGeometryValues()

bool QgsVectorDataProvider::changeGeometryValues ( const QgsGeometryMap & geometry_map )

virtual

Changes geometries of existing features.

Parameters

geometry_map A QgsGeometryMap whose index contains the feature IDs that will have their geometries changed. The second map parameter being the new geometries themselves

Returns: True in case of success and false in case of failure

Definition at line 103 of file qgsvectordataprovider.cpp.

◆ clearErrors()

void QgsVectorDataProvider::clearErrors ( )

Clear recorded errors.

Definition at line 598 of file qgsvectordataprovider.cpp.

◆ clearMinMaxCache()

void QgsVectorDataProvider::clearMinMaxCache ( )

protected

Definition at line 428 of file qgsvectordataprovider.cpp.

◆ convertToProviderType()

QgsGeometry * QgsVectorDataProvider::convertToProviderType ( const QgsGeometry * geom ) const

protected

Converts the geometry to the provider type if possible / necessary this is the list of possible modifications:

convert compoundcurve to circularstring (possible if compoundcurve consists of one circular string)
convert to multitype if necessary
convert to curved type if necessary
convert to linear type from curved type
Add z/m 0 default values
Remove z/m QgsVectorLayerEditBuffer::adaptGeometry()
Parameters

geom Geometry to convert

Returns
the converted geometry or nullptr if no conversion was necessary or possible

Definition at line 625 of file qgsvectordataprovider.cpp.

◆ convertValue()

QVariant QgsVectorDataProvider::convertValue	(	QVariant::Type	type,
		const QString &	value
	)

static

Definition at line 520 of file qgsvectordataprovider.cpp.

◆ createAttributeIndex()

bool QgsVectorDataProvider::createAttributeIndex ( int field )

virtual

Create an attribute index on the datasource.

Definition at line 122 of file qgsvectordataprovider.cpp.

◆ createSpatialIndex()

bool QgsVectorDataProvider::createSpatialIndex ( )

virtual

Creates a spatial index on the datasource (if supported by the provider type).

Returns: true in case of success

Definition at line 117 of file qgsvectordataprovider.cpp.

◆ dataComment()

QString QgsVectorDataProvider::dataComment ( ) const

virtual

Return a short comment for the data that this provider is providing access to (e.g.

the comment for postgres table).

Definition at line 55 of file qgsvectordataprovider.cpp.

◆ defaultValue()

QVariant QgsVectorDataProvider::defaultValue	(	int	fieldId,
		bool	forceLazyEval = `false`
	)

virtual

Returns the default value for field specified by fieldId.

If forceLazyEval is set to true, the provider the default value will not be evaluated on server side even if specified in the project properties.

Definition at line 96 of file qgsvectordataprovider.cpp.

◆ deleteAttributes()

bool QgsVectorDataProvider::deleteAttributes ( const QgsAttributeIds & attributes )

virtual

Deletes existing attributes.

Parameters

attributes a set containing indices of attributes

Returns: true in case of success and false in case of failure

Definition at line 78 of file qgsvectordataprovider.cpp.

◆ deleteFeatures()

bool QgsVectorDataProvider::deleteFeatures ( const QgsFeatureIds & id )

virtual

Deletes one or more features.

Parameters

id	list containing feature ids to delete

Returns: true in case of success and false in case of failure

Definition at line 66 of file qgsvectordataprovider.cpp.

◆ doesStrictFeatureTypeCheck()

virtual bool QgsVectorDataProvider::doesStrictFeatureTypeCheck ( ) const

inlinevirtual

Returns true if the provider is strict about the type of inserted features (e.g.

no multipolygon in a polygon layer)

Definition at line 395 of file qgsvectordataprovider.h.

◆ encoding()

QString QgsVectorDataProvider::encoding ( ) const

Get encoding which is used for accessing data.

Definition at line 153 of file qgsvectordataprovider.cpp.

◆ enumValues()

virtual void QgsVectorDataProvider::enumValues	(	int	index,
		QStringList &	enumList
	)

inlinevirtual

Returns the possible enum values of an attribute.

Returns an empty stringlist if a provider does not support enum types or if the given attribute is not an enum type.

Parameters

index	the index of the attribute
enumList	reference to the list to fill

Definition at line 233 of file qgsvectordataprovider.h.

◆ errors()

QStringList QgsVectorDataProvider::errors ( )

Get recorded errors.

Definition at line 608 of file qgsvectordataprovider.cpp.

◆ featureCount()

virtual long QgsVectorDataProvider::featureCount ( ) const

pure virtual

Number of features in the layer.

Returns: long containing number of features

◆ featureSource()

virtual QgsAbstractFeatureSource* QgsVectorDataProvider::featureSource ( ) const

pure virtual

Return feature source object that can be used for querying provider's data.

The returned feature source is independent from provider - any changes to provider's state (e.g. change of subset string) will not be reflected in the feature source, therefore it can be safely used for processing in background without having to care about possible changes within provider that may happen concurrently. Also, even in the case of provider being deleted, any feature source obtained from the provider will be kept alive and working (they are independent and owned by the caller).

Sometimes there are cases when some data needs to be shared between vector data provider and its feature source. In such cases, the implementation must ensure that the data is not susceptible to run condition. For example, if it is possible that both feature source and provider may need reading/writing to some shared data at the same time, some synchronization mechanisms must be used (e.g. mutexes) to prevent data corruption.

Note: added in 2.4

Returns: new instance of QgsAbstractFeatureSource (caller is responsible for deleting it)

◆ fieldNameIndex()

int QgsVectorDataProvider::fieldNameIndex ( const QString & fieldName ) const

Returns the index of a field name or -1 if the field does not exist.

Definition at line 264 of file qgsvectordataprovider.cpp.

◆ fieldNameMap()

QMap< QString, int > QgsVectorDataProvider::fieldNameMap ( ) const

Return a map where the key is the name of the field and the value is its index.

Definition at line 269 of file qgsvectordataprovider.cpp.

◆ fields()

virtual const QgsFields& QgsVectorDataProvider::fields ( ) const

pure virtual

Return a map of indexes with field names for this layer.

Returns: map of fields

See also: QgsFields

◆ fillMinMaxCache()

void QgsVectorDataProvider::fillMinMaxCache ( )

protected

Definition at line 433 of file qgsvectordataprovider.cpp.

◆ forceReload()

virtual void QgsVectorDataProvider::forceReload ( )

inlinevirtual

Forces a reload of the underlying datasource if the provider implements this method.

In particular on the OGR provider, a pooled connection will be invalidated. This forces QGIS to reopen a file or connection. This can be required if the underlying file is replaced.

Definition at line 436 of file qgsvectordataprovider.h.

◆ geometryType()

virtual QGis::WkbType QgsVectorDataProvider::geometryType ( ) const

pure virtual

Get feature type.

Returns: int representing the feature type

◆ getFeatures()

virtual QgsFeatureIterator QgsVectorDataProvider::getFeatures ( const QgsFeatureRequest & request = QgsFeatureRequest() )

pure virtual

Query the provider for features specified in request.

◆ hasErrors()

bool QgsVectorDataProvider::hasErrors ( )

Provider has errors to report.

Definition at line 603 of file qgsvectordataprovider.cpp.

◆ isSaveAndLoadStyleToDBSupported()

virtual bool QgsVectorDataProvider::isSaveAndLoadStyleToDBSupported ( )

inlinevirtual

It returns false by default.

Must be implemented by providers that support saving and loading styles to db returning true

Definition at line 420 of file qgsvectordataprovider.h.

◆ layerDependencies()

QSet< QString > QgsVectorDataProvider::layerDependencies ( ) const

virtual

Get the list of layer ids on which this layer depends.

This in particular determines the order of layer loading.

Definition at line 620 of file qgsvectordataprovider.cpp.

◆ maximumValue()

QVariant QgsVectorDataProvider::maximumValue ( int index )

virtual

Returns the maximum value of an attribute.

Parameters

index the index of the attribute

Default implementation walks all numeric attributes and caches minimal and maximal values. If provider has facilities to retrieve maximal value directly, override this function.

Definition at line 376 of file qgsvectordataprovider.cpp.

◆ minimumValue()

QVariant QgsVectorDataProvider::minimumValue ( int index )

virtual

Returns the minimum value of an attribute.

Parameters

index the index of the attribute

Default implementation walks all numeric attributes and caches minimal and maximal values. If provider has facilities to retrieve minimal value directly, override this function.

Definition at line 360 of file qgsvectordataprovider.cpp.

◆ nativeTypes()

const QList< QgsVectorDataProvider::NativeType > & QgsVectorDataProvider::nativeTypes ( ) const

Returns the names of the supported types.

Definition at line 287 of file qgsvectordataprovider.cpp.

◆ palAttributeIndexNames()

virtual QgsAttrPalIndexNameHash QgsVectorDataProvider::palAttributeIndexNames ( ) const

inlinevirtual

Return list of indexes to names for QgsPalLabeling fix.

Definition at line 358 of file qgsvectordataprovider.h.

◆ pkAttributeIndexes()

virtual QgsAttributeList QgsVectorDataProvider::pkAttributeIndexes ( )

inlinevirtual

Return list of indexes of fields that make up the primary key.

Definition at line 353 of file qgsvectordataprovider.h.

◆ pushError()

void QgsVectorDataProvider::pushError ( const QString & msg )

protected

Definition at line 613 of file qgsvectordataprovider.cpp.

◆ raiseError

void QgsVectorDataProvider::raiseError ( const QString & msg )

signal

Signals an error in this provider.

◆ renameAttributes()

bool QgsVectorDataProvider::renameAttributes ( const QgsFieldNameMap & renamedAttributes )

virtual

Renames existing attributes.

Parameters

renamedAttributes map of attribute index to new attribute name

Returns: true in case of success and false in case of failure

Note: added in QGIS 2.16

Definition at line 84 of file qgsvectordataprovider.cpp.

◆ setEncoding()

void QgsVectorDataProvider::setEncoding ( const QString & e )

virtual

Set encoding used for accessing data from layer.

Definition at line 134 of file qgsvectordataprovider.cpp.

◆ storageType()

QString QgsVectorDataProvider::storageType ( ) const

virtual

Returns the permanent storage type for this layer as a friendly name.

Definition at line 50 of file qgsvectordataprovider.cpp.

◆ supportedType()

bool QgsVectorDataProvider::supportedType ( const QgsField & field ) const

check if provider supports type of field

Definition at line 292 of file qgsvectordataprovider.cpp.

◆ transaction()

virtual QgsTransaction* QgsVectorDataProvider::transaction ( ) const

inlinevirtual

Returns the transaction this data provider is included in, if any.

Definition at line 427 of file qgsvectordataprovider.h.

◆ uniqueValues()

void QgsVectorDataProvider::uniqueValues	(	int	index,
		QList< QVariant > &	uniqueValues,
		int	limit = `-1`
	)

virtual

Return unique values of an attribute.

Parameters

index	the index of the attribute
uniqueValues	values reference to the list to fill
limit	maxmum number of the values to return

Default implementation simply iterates the features

Definition at line 392 of file qgsvectordataprovider.cpp.

Friends And Related Function Documentation

◆ QgsTransaction

friend class QgsTransaction

friend

Definition at line 54 of file qgsvectordataprovider.h.

◆ QgsVectorLayerEditBuffer

friend class QgsVectorLayerEditBuffer

friend

Definition at line 55 of file qgsvectordataprovider.h.

Member Data Documentation

◆ EditingCapabilities

const int QgsVectorDataProvider::EditingCapabilities

static

Initial value:

= AddFeatures | DeleteFeatures |
                                           ChangeAttributeValues | ChangeGeometries | AddAttributes | DeleteAttributes |
                                           RenameAttributes

Bitmask of all provider's editing capabilities.

Definition at line 112 of file qgsvectordataprovider.h.

◆ mAttributesToFetch

QgsAttributeList QgsVectorDataProvider::mAttributesToFetch

protected

List of attribute indices to fetch with nextFeature calls.

Definition at line 461 of file qgsvectordataprovider.h.

◆ mAttrPalIndexName

QgsAttrPalIndexNameHash QgsVectorDataProvider::mAttrPalIndexName

protected

Old-style mapping of index to name for QgsPalLabeling fix.

Definition at line 469 of file qgsvectordataprovider.h.

◆ mCacheMaxValues

QMap<int, QVariant> QgsVectorDataProvider::mCacheMaxValues

protected

Definition at line 455 of file qgsvectordataprovider.h.

◆ mCacheMinMaxDirty

bool QgsVectorDataProvider::mCacheMinMaxDirty

protected

Definition at line 454 of file qgsvectordataprovider.h.

◆ mCacheMinValues

QMap<int, QVariant> QgsVectorDataProvider::mCacheMinValues

protected

Definition at line 455 of file qgsvectordataprovider.h.

◆ mEncoding

QTextCodec* QgsVectorDataProvider::mEncoding

protected

Encoding.

Definition at line 458 of file qgsvectordataprovider.h.

◆ mNativeTypes

QList< NativeType > QgsVectorDataProvider::mNativeTypes

protected

The names of the providers native types.

Definition at line 464 of file qgsvectordataprovider.h.

The documentation for this class was generated from the following files:

/tmp/buildd/qgis-2.18.21+99unstable/src/core/qgsvectordataprovider.h
/tmp/buildd/qgis-2.18.21+99unstable/src/core/qgsvectordataprovider.cpp

Classes

Public Types

Signals

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Friends

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ Capability

Constructor & Destructor Documentation

◆ QgsVectorDataProvider()

◆ ~QgsVectorDataProvider()

Member Function Documentation

◆ addAttributes()

◆ addFeatures()

◆ aggregate()

◆ attributeIndexes()

◆ availableEncodings()

◆ capabilities()

◆ capabilitiesString()

◆ changeAttributeValues()

◆ changeFeatures()

◆ changeGeometryValues()

◆ clearErrors()

◆ clearMinMaxCache()

◆ convertToProviderType()

◆ convertValue()

◆ createAttributeIndex()

◆ createSpatialIndex()

◆ dataComment()

◆ defaultValue()

◆ deleteAttributes()

◆ deleteFeatures()

◆ doesStrictFeatureTypeCheck()

◆ encoding()

◆ enumValues()

◆ errors()

◆ featureCount()

◆ featureSource()

◆ fieldNameIndex()

◆ fieldNameMap()

◆ fields()

◆ fillMinMaxCache()

◆ forceReload()

◆ geometryType()

◆ getFeatures()

◆ hasErrors()

◆ isSaveAndLoadStyleToDBSupported()

◆ layerDependencies()

◆ maximumValue()

◆ minimumValue()

◆ nativeTypes()

◆ palAttributeIndexNames()

◆ pkAttributeIndexes()

◆ pushError()

◆ raiseError

◆ renameAttributes()

◆ setEncoding()

◆ storageType()

◆ supportedType()

◆ transaction()

◆ uniqueValues()

Friends And Related Function Documentation

◆ QgsTransaction

◆ QgsVectorLayerEditBuffer

Member Data Documentation

◆ EditingCapabilities

◆ mAttributesToFetch

◆ mAttrPalIndexName

◆ mCacheMaxValues

◆ mCacheMinMaxDirty

◆ mCacheMinValues

◆ mEncoding

◆ mNativeTypes