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QgsRelation Class Reference

#include <qgsrelation.h>

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 ()
 

Constructor & Destructor Documentation

QgsRelation::QgsRelation ( )

Default constructor.

Creates an invalid relation.

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)
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
Note
not available in python bindings
QgsRelation QgsRelation::createFromXML ( const QDomNode &  node)
static

Creates a relation from an XML structure.

Used for reading .qgs projects.

Parameters
nodeThe dom node containing the relation information
Returns
A relation
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
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
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
const QString & QgsRelation::id ( ) const

The id.

Returns
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
const QString QgsRelation::name ( ) const
QgsVectorLayer * QgsRelation::referencedLayer ( ) const

Access the referenced (parent) layer.

Returns
referenced layer
QString QgsRelation::referencedLayerId ( ) const

Access the referenced (parent) layer's id.

Returns
The id of the referenced layer
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
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
void QgsRelation::runChecks ( )
protected
void QgsRelation::setReferencedLayer ( QString  id)

Set the referenced layer id.

This layer will be searched in the registry.

Parameters
id
void QgsRelation::setReferencingLayer ( QString  id)

Set the referencing layer id.

This layer will be searched in the registry.

Parameters
id
void QgsRelation::setRelationId ( QString  id)

Set a name for this relation.

Parameters
id
void QgsRelation::setRelationName ( QString  name)

Set a name for this relation.

Parameters
name
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

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