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QgsRelation Class Reference

#include <qgsrelation.h>

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Classes

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

Public Member Functions

 QgsRelation ()
 Default constructor. More...
 
void writeXML (QDomNode &node, QDomDocument &doc) const
 Writes a relation to an XML structure. More...
 
void setRelationId (QString id)
 Set a name for this relation. More...
 
void setRelationName (QString name)
 Set a name for this relation. More...
 
void setReferencingLayer (QString id)
 Set the referencing layer id. More...
 
void setReferencedLayer (QString id)
 Set the referenced layer id. More...
 
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. More...
 
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. More...
 
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. More...
 
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. More...
 
const QString name () const
 
const QString & id () const
 The id. More...
 
QString referencingLayerId () const
 Access the referencing (child) layer's id This is the layer which has the field(s) which point to another layer. More...
 
QgsVectorLayerreferencingLayer () const
 Access the referencing (child) layer This is the layer which has the field(s) which point to another layer. More...
 
QString referencedLayerId () const
 Access the referenced (parent) layer's id. More...
 
QgsVectorLayerreferencedLayer () const
 Access the referenced (parent) layer. More...
 
QList< FieldPairfieldPairs () const
 Returns the field pairs which form this relation The first element of each pair are the field names fo the foreign key. More...
 
bool isValid () const
 Returns the validity of this relation. More...
 

Static Public Member Functions

static QgsRelation createFromXML (const QDomNode &node)
 Creates a relation from an XML structure. More...
 

Protected Member Functions

void updateRelationStatus ()
 
void runChecks ()
 

Private Attributes

QString mRelationId
 Unique Id. More...
 
QString mRelationName
 Human redable name. More...
 
QString mReferencingLayerId
 The child layer. More...
 
QgsVectorLayermReferencingLayer
 The child layer. More...
 
QString mReferencedLayerId
 The parent layer id. More...
 
QgsVectorLayermReferencedLayer
 The parent layer. More...
 
QList< FieldPairmFieldPairs
 A list of fields which define the relation. More...
 
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
referencingFieldThe field name on the referencing layer (FK)
referencedFieldThe 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
fieldPairA pair of two strings

Definition at line 141 of file qgsrelation.cpp.

References mFieldPairs, and updateRelationStatus().

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

Writes a relation to an XML structure.

Used for saving .qgs projects

Parameters
nodeThe parent node in which the relation will be created
docThe 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().

QgsVectorLayer* QgsRelation::mReferencedLayer
private

The parent layer.

Definition at line 214 of file qgsrelation.h.

Referenced by createFromXML(), referencedLayer(), and updateRelationStatus().

QString QgsRelation::mReferencedLayerId
private

The parent layer id.

Definition at line 212 of file qgsrelation.h.

Referenced by createFromXML(), referencedLayerId(), setReferencedLayer(), updateRelationStatus(), and writeXML().

QgsVectorLayer* QgsRelation::mReferencingLayer
private

The child layer.

Definition at line 210 of file qgsrelation.h.

Referenced by createFromXML(), referencingLayer(), and updateRelationStatus().

QString QgsRelation::mReferencingLayerId
private

The child layer.

Definition at line 208 of file qgsrelation.h.

Referenced by createFromXML(), referencingLayerId(), setReferencingLayer(), updateRelationStatus(), and writeXML().

QString QgsRelation::mRelationId
private

Unique Id.

Definition at line 204 of file qgsrelation.h.

Referenced by createFromXML(), id(), setRelationId(), and writeXML().

QString QgsRelation::mRelationName
private

Human redable name.

Definition at line 206 of file qgsrelation.h.

Referenced by createFromXML(), name(), setRelationName(), and writeXML().

bool QgsRelation::mValid
private

Definition at line 221 of file qgsrelation.h.

Referenced by isValid(), and updateRelationStatus().


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