#include <qgsrelation.h>

Collaboration diagram for QgsRelation:

Classes
class	FieldPair
	Defines a relation between matchin fields of the two involved tables of a relation. More...

Public Member Functions
	QgsRelation ()
	Default constructor.
void	writeXML (QDomNode &node, QDomDocument &doc) const
	Writes a relation to an XML structure.
void	setRelationId (QString id)
	Set a name for this relation.
void	setRelationName (QString name)
	Set a name for this relation.
void	setReferencingLayer (QString id)
	Set the referencing layer id.
void	setReferencedLayer (QString id)
	Set the referenced layer id.
void	addFieldPair (QString referencingField, QString referencedField)
	Add a field pairs which is part of this relation The first element of each pair are the field names fo the foreign key.
void	addFieldPair (FieldPair fieldPair)
	Add a field pairs which is part of this relation The first element of each pair are the field names fo the foreign key.
QgsFeatureIterator	getRelatedFeatures (const QgsFeature &feature) const
	Creates an iterator which returns all the features on the referencing (child) layer which have a foreign key pointing to the provided feature.
QgsFeatureRequest	getRelatedFeaturesRequest (const QgsFeature &feature) const
	Creates a request to return all the features on the referencing (child) layer which have a foreign key pointing to the provided feature.
const QString	name () const
const QString &	id () const
	The id.
QString	referencingLayerId () const
	Access the referencing (child) layer's id This is the layer which has the field(s) which point to another layer.
QgsVectorLayer *	referencingLayer () const
	Access the referencing (child) layer This is the layer which has the field(s) which point to another layer.
QString	referencedLayerId () const
	Access the referenced (parent) layer's id.
QgsVectorLayer *	referencedLayer () const
	Access the referenced (parent) layer.
QList< FieldPair >	fieldPairs () const
	Returns the field pairs which form this relation The first element of each pair are the field names fo the foreign key.
bool	isValid () const
	Returns the validity of this relation.

Static Public Member Functions
static QgsRelation	createFromXML (const QDomNode &node)
	Creates a relation from an XML structure.

Protected Member Functions
void	updateRelationStatus ()
void	runChecks ()

Private Attributes
QString	mRelationId
	Unique Id.
QString	mRelationName
	Human redable name.
QString	mReferencingLayerId
	The child layer.
QgsVectorLayer *	mReferencingLayer
	The child layer.
QString	mReferencedLayerId
	The parent layer id.
QgsVectorLayer *	mReferencedLayer
	The parent layer.
QList< FieldPair >	mFieldPairs
	A list of fields which define the relation.
bool	mValid

Detailed Description

Definition at line 28 of file qgsrelation.h.

Constructor & Destructor Documentation

QgsRelation::QgsRelation ( )

Default constructor.

Creates an invalid relation.

Definition at line 23 of file qgsrelation.cpp.

Member Function Documentation

void QgsRelation::addFieldPair	(	QString	referencingField,
		QString	referencedField
	)

Add a field pairs which is part of this relation The first element of each pair are the field names fo the foreign key.

The second element of each pair are the field names of the matching primary key.

Parameters

referencingField	The field name on the referencing layer (FK)
referencedField	The field name on the referenced layer (PK)

Definition at line 135 of file qgsrelation.cpp.

References mFieldPairs, and updateRelationStatus().

Referenced by createFromXML(), and QgsRelationManagerDialog::on_mBtnAddRelation_clicked().

void QgsRelation::addFieldPair ( QgsRelation::FieldPair fieldPair )

Add a field pairs which is part of this relation The first element of each pair are the field names fo the foreign key.

The second element of each pair are the field names of the matching primary key.

Parameters

fieldPair A pair of two strings

Definition at line 141 of file qgsrelation.cpp.

References mFieldPairs, and updateRelationStatus().

QgsRelation QgsRelation::createFromXML ( const QDomNode & node )

static

Creates a relation from an XML structure.

Used for reading .qgs projects.

Parameters

node	The dom node containing the relation information

Returns: A relation

Definition at line 30 of file qgsrelation.cpp.

References addFieldPair(), id(), QgsMapLayerRegistry::instance(), QgsMapLayerRegistry::mapLayers(), mReferencedLayer, mReferencedLayerId, mReferencingLayer, mReferencingLayerId, mRelationId, mRelationName, name(), referencedLayer(), referencedLayerId(), referencingLayer(), referencingLayerId(), QgsMapLayer::type(), updateRelationStatus(), QgsMapLayer::VectorLayer, and QgsLogger::warning().

Referenced by QgsRelationManager::readProject().

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

Returns the field pairs which form this relation The first element of each pair are the field names fo the foreign key.

The second element of each pair are the field names of the matching primary key.

Returns: The fields forming the relation

Definition at line 214 of file qgsrelation.cpp.

References mFieldPairs.

Referenced by QgsRelationManagerDialog::addRelation(), QgsRelationEditorWidget::on_mAddFeatureButton_clicked(), QgsRelationEditorWidget::on_mLinkFeatureButton_clicked(), QgsRelationEditorWidget::on_mUnlinkFeatureButton_clicked(), and QgsRelationManager::referencingRelations().

QgsFeatureIterator QgsRelation::getRelatedFeatures ( const QgsFeature & feature ) const

Creates an iterator which returns all the features on the referencing (child) layer which have a foreign key pointing to the provided feature.

Parameters

feature A feature from the referenced (parent) layer

Returns: An iterator with all the referenced features

Definition at line 147 of file qgsrelation.cpp.

References QgsVectorLayer::getFeatures(), getRelatedFeaturesRequest(), and referencingLayer().

QgsFeatureRequest QgsRelation::getRelatedFeaturesRequest ( const QgsFeature & feature ) const

Creates a request to return all the features on the referencing (child) layer which have a foreign key pointing to the provided feature.

Parameters

feature A feature from the referenced (parent) layer

Returns: An request for all the referenced features

Definition at line 152 of file qgsrelation.cpp.

References QgsFields::at(), QgsFeature::attribute(), QgsFields::indexFromName(), mFieldPairs, QgsVectorLayer::pendingFields(), QgsDebugMsg, QgsRelation::FieldPair::referencedField(), QgsRelation::FieldPair::referencingField(), referencingLayer(), QgsFeatureRequest::setFilterExpression(), and QgsField::type().

Referenced by QgsRelationEditorWidget::createRelationEditor(), and getRelatedFeatures().

const QString & QgsRelation::id ( ) const

The id.

Returns

Definition at line 189 of file qgsrelation.cpp.

References mRelationId.

Referenced by QgsRelationManagerDialog::addRelation(), QgsRelationManager::addRelation(), createFromXML(), QgsAttributeDialog::init(), QgsRelationManagerDialog::on_mBtnAddRelation_clicked(), QgsRelationManager::removeRelation(), setReferencedLayer(), setReferencingLayer(), setRelationId(), and QgsAttributeEditorRelation::toDomElement().

bool QgsRelation::isValid ( ) const

Returns the validity of this relation.

Don't use the information if it's not valid.

Returns: true if the relation is valid

Definition at line 219 of file qgsrelation.cpp.

References mValid.

Referenced by QgsRelationManager::addRelation(), QgsAttributeDialog::init(), and QgsAttributeEditorRelation::init().

const QString QgsRelation::name ( ) const

Definition at line 184 of file qgsrelation.cpp.

References mRelationName.

Referenced by QgsRelationManagerDialog::addRelation(), createFromXML(), and setRelationName().

QgsVectorLayer * QgsRelation::referencedLayer ( ) const

Access the referenced (parent) layer.

Returns: referenced layer

Definition at line 209 of file qgsrelation.cpp.

References mReferencedLayer.

Referenced by QgsRelationManagerDialog::addRelation(), createFromXML(), and QgsRelationManager::referencedRelations().

QString QgsRelation::referencedLayerId ( ) const

Access the referenced (parent) layer's id.

Returns: The id of the referenced layer

Definition at line 204 of file qgsrelation.cpp.

References mReferencedLayerId.

Referenced by createFromXML().

QgsVectorLayer * QgsRelation::referencingLayer ( ) const

Access the referencing (child) layer This is the layer which has the field(s) which point to another layer.

Returns: The referencing layer

Definition at line 199 of file qgsrelation.cpp.

References mReferencingLayer.

QString QgsRelation::referencingLayerId ( ) const

Access the referencing (child) layer's id This is the layer which has the field(s) which point to another layer.

Returns: The id of the referencing layer

Definition at line 194 of file qgsrelation.cpp.

References mReferencingLayerId.

Referenced by createFromXML().

void QgsRelation::runChecks ( )

protected

Definition at line 255 of file qgsrelation.cpp.

void QgsRelation::setReferencedLayer ( QString id )

Set the referenced layer id.

This layer will be searched in the registry.

Parameters

id

Definition at line 128 of file qgsrelation.cpp.

References id(), mReferencedLayerId, and updateRelationStatus().

Referenced by QgsRelationManagerDialog::on_mBtnAddRelation_clicked().

void QgsRelation::setReferencingLayer ( QString id )

Set the referencing layer id.

This layer will be searched in the registry.

Parameters

id

Definition at line 121 of file qgsrelation.cpp.

References id(), mReferencingLayerId, and updateRelationStatus().

Referenced by QgsRelationManagerDialog::on_mBtnAddRelation_clicked().

void QgsRelation::setRelationId ( QString id )

Set a name for this relation.

Parameters

id

Definition at line 111 of file qgsrelation.cpp.

References id(), and mRelationId.

Referenced by QgsRelationManagerDialog::on_mBtnAddRelation_clicked().

void QgsRelation::setRelationName ( QString name )

Set a name for this relation.

Parameters

name

Definition at line 116 of file qgsrelation.cpp.

References mRelationName, and name().

Referenced by QgsRelationManagerDialog::on_mBtnAddRelation_clicked(), and QgsRelationManagerDialog::relations().

void QgsRelation::updateRelationStatus ( )

protected

Definition at line 224 of file qgsrelation.cpp.

References QgsVectorLayer::fieldNameIndex(), QgsMapLayerRegistry::instance(), QgsMapLayerRegistry::mapLayers(), mFieldPairs, mReferencedLayer, mReferencedLayerId, mReferencingLayer, mReferencingLayerId, and mValid.

Referenced by addFieldPair(), createFromXML(), setReferencedLayer(), and setReferencingLayer().

void QgsRelation::writeXML	(	QDomNode &	node,
		QDomDocument &	doc
	)		const

Writes a relation to an XML structure.

Used for saving .qgs projects

Parameters

node	The parent node in which the relation will be created
doc	The document in which the relation will be saved

Definition at line 92 of file qgsrelation.cpp.

References mFieldPairs, mReferencedLayerId, mReferencingLayerId, mRelationId, and mRelationName.

Referenced by QgsRelationManager::writeProject().

Member Data Documentation

QList< FieldPair > QgsRelation::mFieldPairs

private

A list of fields which define the relation.

In most cases there will be only one value, but multiple values are supported for composited foreign keys. The first field is on the referencing layer, the second on the referenced

Definition at line 219 of file qgsrelation.h.

Referenced by addFieldPair(), fieldPairs(), getRelatedFeaturesRequest(), updateRelationStatus(), and writeXML().