QGIS API Documentation
2.18.21-Las Palmas (9fba24a)
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#include <qgsrelation.h>
Classes | |
class | FieldPair |
Defines a relation between matching fields of the two involved tables of a relation. More... | |
Public Member Functions | |
QgsRelation () | |
Default constructor. More... | |
void | addFieldPair (const QString &referencingField, const QString &referencedField) |
Add a field pairs which is part of this relation The first element of each pair are the field names of the foreign key. More... | |
void | addFieldPair (const FieldPair &fieldPair) |
Add a field pairs which is part of this relation The first element of each pair are the field names of the foreign key. More... | |
QList< FieldPair > | fieldPairs () const |
Returns the field pairs which form this relation The first element of each pair are the field names of the foreign key. More... | |
QgsFeature | getReferencedFeature (const QgsFeature &feature) const |
Creates a request to return the feature on the referenced (parent) layer which is referenced by the provided feature. More... | |
QgsFeatureRequest | getReferencedFeatureRequest (const QgsAttributes &attributes) const |
Creates a request to return the feature on the referenced (parent) layer which is referenced by the provided feature. More... | |
QgsFeatureRequest | getReferencedFeatureRequest (const QgsFeature &feature) const |
Creates a request to return the feature on the referenced (parent) layer which is referenced by the provided feature. 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... | |
QString | getRelatedFeaturesFilter (const QgsFeature &feature) const |
Returns a filter expression 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... | |
QString | id () const |
A (project-wide) unique id for this relation. More... | |
bool | isValid () const |
Returns the validity of this relation. More... | |
QString | name () const |
Returns a human readable name for this relation. More... | |
QgsAttributeList | referencedFields () const |
Returns a list of attributes used to form the referenced fields (most likely primary key) on the referenced (parent) layer. More... | |
QgsVectorLayer * | referencedLayer () const |
Access the referenced (parent) layer. More... | |
QString | referencedLayerId () const |
Access the referenced (parent) layer's id. More... | |
QgsAttributeList | referencingFields () const |
Returns a list of attributes used to form the referencing fields (foreign key) on the referencing (child) layer. More... | |
QgsVectorLayer * | referencingLayer () const |
Access the referencing (child) layer This is the layer which has the field(s) which point to another layer. 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... | |
void | setReferencedLayer (const QString &id) |
Set the referenced (parent) layer id. More... | |
void | setReferencingLayer (const QString &id) |
Set the referencing (child) layer id. More... | |
void | setRelationId (const QString &id) |
Set a name for this relation. More... | |
void | setRelationName (const QString &name) |
Set a name for this relation. More... | |
void | writeXML (QDomNode &node, QDomDocument &doc) const |
Writes a relation to an XML structure. More... | |
Static Public Member Functions | |
static QgsRelation | createFromXML (const QDomNode &node) |
Creates a relation from an XML structure. More... | |
Protected Member Functions | |
void | updateRelationStatus () |
Updates the validity status of this relation. More... | |
Definition at line 31 of file qgsrelation.h.
QgsRelation::QgsRelation | ( | ) |
void QgsRelation::addFieldPair | ( | const QString & | referencingField, |
const QString & | referencedField | ||
) |
Add a field pairs which is part of this relation The first element of each pair are the field names of the foreign key.
The second element of each pair are the field names of the matching primary key.
referencingField | The field name on the referencing (child) layer (FK) |
referencedField | The field name on the referenced (parent) layer (PK) |
Definition at line 137 of file qgsrelation.cpp.
void QgsRelation::addFieldPair | ( | const FieldPair & | fieldPair | ) |
Add a field pairs which is part of this relation The first element of each pair are the field names of the foreign key.
The second element of each pair are the field names of the matching primary key.
fieldPair | A pair of two strings |
Definition at line 143 of file qgsrelation.cpp.
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static |
Creates a relation from an XML structure.
Used for reading .qgs projects.
node | The dom node containing the relation information |
Definition at line 30 of file qgsrelation.cpp.
QList< QgsRelation::FieldPair > QgsRelation::fieldPairs | ( | ) | const |
Returns the field pairs which form this relation The first element of each pair are the field names of the foreign key.
The second element of each pair are the field names of the matching primary key.
Definition at line 240 of file qgsrelation.cpp.
QgsFeature QgsRelation::getReferencedFeature | ( | const QgsFeature & | feature | ) | const |
Creates a request to return the feature on the referenced (parent) layer which is referenced by the provided feature.
feature | A feature from the referencing (child) layer |
Definition at line 201 of file qgsrelation.cpp.
QgsFeatureRequest QgsRelation::getReferencedFeatureRequest | ( | const QgsAttributes & | attributes | ) | const |
Creates a request to return the feature on the referenced (parent) layer which is referenced by the provided feature.
attributes | An attribute vector containing the foreign key |
Definition at line 177 of file qgsrelation.cpp.
QgsFeatureRequest QgsRelation::getReferencedFeatureRequest | ( | const QgsFeature & | feature | ) | const |
Creates a request to return the feature on the referenced (parent) layer which is referenced by the provided feature.
feature | A feature from the referencing (child) layer |
Definition at line 196 of file qgsrelation.cpp.
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.
feature | A feature from the referenced (parent) layer |
Definition at line 149 of file qgsrelation.cpp.
QString QgsRelation::getRelatedFeaturesFilter | ( | const QgsFeature & | feature | ) | const |
Returns a filter expression which returns all the features on the referencing (child) layer which have a foreign key pointing to the provided feature.
feature | A feature from the referenced (parent) layer |
Definition at line 164 of file qgsrelation.cpp.
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.
feature | A feature from the referenced (parent) layer |
Definition at line 154 of file qgsrelation.cpp.
QString QgsRelation::id | ( | ) | const |
A (project-wide) unique id for this relation.
Definition at line 215 of file qgsrelation.cpp.
bool QgsRelation::isValid | ( | ) | const |
Returns the validity of this relation.
Don't use the information if it's not valid.
Definition at line 268 of file qgsrelation.cpp.
QString QgsRelation::name | ( | ) | const |
Returns a human readable name for this relation.
Mostly used as title for the children.
Definition at line 210 of file qgsrelation.cpp.
QgsAttributeList QgsRelation::referencedFields | ( | ) | const |
Returns a list of attributes used to form the referenced fields (most likely primary key) on the referenced (parent) layer.
Definition at line 245 of file qgsrelation.cpp.
QgsVectorLayer * QgsRelation::referencedLayer | ( | ) | const |
Access the referenced (parent) layer.
Definition at line 235 of file qgsrelation.cpp.
QString QgsRelation::referencedLayerId | ( | ) | const |
Access the referenced (parent) layer's id.
Definition at line 230 of file qgsrelation.cpp.
QgsAttributeList QgsRelation::referencingFields | ( | ) | const |
Returns a list of attributes used to form the referencing fields (foreign key) on the referencing (child) layer.
Definition at line 256 of file qgsrelation.cpp.
QgsVectorLayer * QgsRelation::referencingLayer | ( | ) | const |
Access the referencing (child) layer This is the layer which has the field(s) which point to another layer.
Definition at line 225 of file qgsrelation.cpp.
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.
Definition at line 220 of file qgsrelation.cpp.
void QgsRelation::setReferencedLayer | ( | const QString & | id | ) |
Set the referenced (parent) layer id.
This layer will be searched in the registry.
id |
Definition at line 130 of file qgsrelation.cpp.
void QgsRelation::setReferencingLayer | ( | const QString & | id | ) |
Set the referencing (child) layer id.
This layer will be searched in the registry.
id |
Definition at line 123 of file qgsrelation.cpp.
void QgsRelation::setRelationId | ( | const QString & | id | ) |
void QgsRelation::setRelationName | ( | const QString & | name | ) |
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protected |
Updates the validity status of this relation.
Will be called internally whenever a member is changed.
Definition at line 273 of file qgsrelation.cpp.
void QgsRelation::writeXML | ( | QDomNode & | node, |
QDomDocument & | doc | ||
) | const |
Writes a relation to an XML structure.
Used for saving .qgs projects
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.