The QgsWeakRelation class represent a QgsRelation with possibly unresolved layers or unmatched fields. More...

#include <qgsweakrelation.h>

Public Types
enum	WeakRelationType { Referencing , Referenced }
	Enum to distinguish if the layer is referenced or referencing. More...

Public Member Functions
	QgsWeakRelation (const QString &relationId, const QString &relationName, const QgsRelation::RelationStrength strength, const QString &referencingLayerId, const QString &referencingLayerName, const QString &referencingLayerSource, const QString &referencingLayerProviderKey, const QString &referencedLayerId, const QString &referencedLayerName, const QString &referencedLayerSource, const QString &referencedLayerProviderKey, const QList< QgsRelation::FieldPair > &fieldPairs)
	Creates a QgsWeakRelation. More...

QList< QgsRelation::FieldPair >	fieldPairs () const
	Returns the list of field pairs. More...

QgsVectorLayerRef	referencedLayer () const
	Returns a weak reference to the referenced layer. More...

QgsVectorLayerRef	referencingLayer () const
	Returns a weak reference to the referencing layer. More...

QgsRelation	resolvedRelation (const QgsProject *project, QgsVectorLayerRef::MatchType matchType=QgsVectorLayerRef::MatchType::All) const
	Resolves a weak relation in the given project returning a possibly invalid QgsRelation and without performing any kind of validity check. More...

QgsRelation::RelationStrength	strength () const
	Returns the strength of the relation. More...

Static Public Member Functions
static QgsWeakRelation	readXml (const QgsVectorLayer *layer, WeakRelationType type, const QDomNode &node, const QgsPathResolver resolver)
	Returns a weak relation for the given layer. More...

static void	writeXml (const QgsVectorLayer *layer, WeakRelationType type, const QgsRelation &relation, QDomNode &node, QDomDocument &doc)
	Writes a weak relation infoto an XML structure. More...

Friends
class	TestQgsWeakRelation

Detailed Description

The QgsWeakRelation class represent a QgsRelation with possibly unresolved layers or unmatched fields.

This class is used to store relation information attached to a layer style, a method to attempt relation resolution is also implemented and can be used to create a QgsRelation after the dependent layers are loaded and available.

Note: not available in Python bindings

Since: QGIS 3.12

Definition at line 38 of file qgsweakrelation.h.

Member Enumeration Documentation

◆ WeakRelationType

enum QgsWeakRelation::WeakRelationType

Enum to distinguish if the layer is referenced or referencing.

Since: QGIS 3.16

Enumerator
Referencing	The layer is referencing.
Referenced	The layer is referenced.

Definition at line 46 of file qgsweakrelation.h.

Constructor & Destructor Documentation

◆ QgsWeakRelation()

QgsWeakRelation::QgsWeakRelation	(	const QString &	relationId,
		const QString &	relationName,
		const QgsRelation::RelationStrength	strength,
		const QString &	referencingLayerId,
		const QString &	referencingLayerName,
		const QString &	referencingLayerSource,
		const QString &	referencingLayerProviderKey,
		const QString &	referencedLayerId,
		const QString &	referencedLayerName,
		const QString &	referencedLayerSource,
		const QString &	referencedLayerProviderKey,
		const QList< QgsRelation::FieldPair > &	fieldPairs
	)

Creates a QgsWeakRelation.

Definition at line 22 of file qgsweakrelation.cpp.

Member Function Documentation

◆ fieldPairs()

QList< QgsRelation::FieldPair > QgsWeakRelation::fieldPairs ( ) const

Returns the list of field pairs.

Definition at line 75 of file qgsweakrelation.cpp.

◆ readXml()

QgsWeakRelation QgsWeakRelation::readXml	(	const QgsVectorLayer *	layer,
		WeakRelationType	type,
		const QDomNode &	node,
		const QgsPathResolver	resolver
	)

static

Returns a weak relation for the given layer.

Parameters

layer	the layer of the weak relation
type	determines if the layer is referencing or referenced
node	the QDomNode
resolver	the path resolver

Since: QGIS 3.16

Definition at line 80 of file qgsweakrelation.cpp.

◆ referencedLayer()

QgsVectorLayerRef QgsWeakRelation::referencedLayer ( ) const

Returns a weak reference to the referenced layer.

Definition at line 65 of file qgsweakrelation.cpp.

◆ referencingLayer()

QgsVectorLayerRef QgsWeakRelation::referencingLayer ( ) const

Returns a weak reference to the referencing layer.

Definition at line 60 of file qgsweakrelation.cpp.

◆ resolvedRelation()

QgsRelation QgsWeakRelation::resolvedRelation	(	const QgsProject *	project,
		QgsVectorLayerRef::MatchType	matchType = `QgsVectorLayerRef::MatchType::All`
	)		const

Resolves a weak relation in the given project returning a possibly invalid QgsRelation and without performing any kind of validity check.

Note: Client code should never assume that the returned relation is valid and the layer components are not NULL.

Definition at line 35 of file qgsweakrelation.cpp.

◆ strength()

QgsRelation::RelationStrength QgsWeakRelation::strength ( ) const

Returns the strength of the relation.

Definition at line 70 of file qgsweakrelation.cpp.

◆ writeXml()

void QgsWeakRelation::writeXml	(	const QgsVectorLayer *	layer,
		WeakRelationType	type,
		const QgsRelation &	relation,
		QDomNode &	node,
		QDomDocument &	doc
	)

static

Writes a weak relation infoto an XML structure.

Used for saving .qgs projects

Parameters

layer	the layer which we save the weak relation for
type	determines if the layer is referencing or referenced
relation	the relation to save as a weak relation
node	The parent node in which the relation will be created
doc	The document in which the relation will be saved

Since: QGIS 3.16

Definition at line 139 of file qgsweakrelation.cpp.

Friends And Related Function Documentation

◆ TestQgsWeakRelation

friend class TestQgsWeakRelation

friend

Definition at line 130 of file qgsweakrelation.h.

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

/build/qgis-3.20.0+99unstable/src/core/qgsweakrelation.h
/build/qgis-3.20.0+99unstable/src/core/qgsweakrelation.cpp

Public Types

Public Member Functions

Static Public Member Functions

Friends