QGIS API Documentation  2.99.0-Master (ba079d8)
Signals | Public Member Functions | Static Public Member Functions | List of all members
QgsRelationManager Class Reference

This class manages a set of relations between layers. More...

#include <qgsrelationmanager.h>

Inheritance diagram for QgsRelationManager:
Inheritance graph
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Signals

void changed ()
 Emitted when relations are added or removed to the manager. More...
 
void relationsLoaded ()
 This signal is emitted when the relations were loaded after reading a project. More...
 

Public Member Functions

 QgsRelationManager (QgsProject *project=nullptr)
 Constructor for QgsRelationManager. More...
 
void addRelation (const QgsRelation &relation)
 Add a relation. More...
 
void clear ()
 Remove any relation managed by this class. More...
 
QList< QgsRelationreferencedRelations (QgsVectorLayer *layer=nullptr) const
 Get all relations where this layer is the referenced part (i.e. More...
 
QList< QgsRelationreferencingRelations (const QgsVectorLayer *layer=nullptr, int fieldIdx=-2) const
 Get all relations where the specified layer (and field) is the referencing part (i.e. More...
 
Q_INVOKABLE QgsRelation relation (const QString &id) const
 Get access to a relation by its id. More...
 
QMap< QString, QgsRelationrelations () const
 Get access to the relations managed by this class. More...
 
QList< QgsRelationrelationsByName (const QString &name) const
 Returns a list of relations with matching names. More...
 
void removeRelation (const QString &id)
 Remove a relation. More...
 
void removeRelation (const QgsRelation &relation)
 Remove a relation. More...
 
void setRelations (const QList< QgsRelation > &relations)
 Will set the specified relations and remove any relation currently set. More...
 

Static Public Member Functions

static QList< QgsRelationdiscoverRelations (const QList< QgsRelation > &existingRelations, const QList< QgsVectorLayer *> &layers)
 Discover all the relations available from the current layers. More...
 

Detailed Description

This class manages a set of relations between layers.

Definition at line 33 of file qgsrelationmanager.h.

Constructor & Destructor Documentation

◆ QgsRelationManager()

QgsRelationManager::QgsRelationManager ( QgsProject project = nullptr)
explicit

Constructor for QgsRelationManager.

Parameters
projectassociated project (used to notify project of changes)

Definition at line 24 of file qgsrelationmanager.cpp.

Member Function Documentation

◆ addRelation()

void QgsRelationManager::addRelation ( const QgsRelation relation)

Add a relation.

Parameters
relationThe relation to add.

Definition at line 48 of file qgsrelationmanager.cpp.

◆ changed

void QgsRelationManager::changed ( )
signal

Emitted when relations are added or removed to the manager.

Since
QGIS 2.5

◆ clear()

void QgsRelationManager::clear ( )

Remove any relation managed by this class.

Definition at line 90 of file qgsrelationmanager.cpp.

◆ discoverRelations()

QList< QgsRelation > QgsRelationManager::discoverRelations ( const QList< QgsRelation > &  existingRelations,
const QList< QgsVectorLayer *> &  layers 
)
static

Discover all the relations available from the current layers.

Parameters
existingRelationsthe existing relations to filter them out
layersthe current layers
Returns
the list of discovered relations
Since
QGIS 3.0

Definition at line 230 of file qgsrelationmanager.cpp.

◆ referencedRelations()

QList< QgsRelation > QgsRelationManager::referencedRelations ( QgsVectorLayer layer = nullptr) const

Get all relations where this layer is the referenced part (i.e.

the parent table with the primary key being referenced from another layer).

Parameters
layerThe layer which should be searched for.
Returns
A list of relations where the specified layer is the referenced part.

Definition at line 133 of file qgsrelationmanager.cpp.

◆ referencingRelations()

QList< QgsRelation > QgsRelationManager::referencingRelations ( const QgsVectorLayer layer = nullptr,
int  fieldIdx = -2 
) const

Get all relations where the specified layer (and field) is the referencing part (i.e.

the child table with the foreign key).

Parameters
layerThe layer which should be searched for.
fieldIdxThe field which should be part of the foreign key. If not set will return all relations.
Returns
A list of relations matching the given layer and fieldIdx.

Definition at line 96 of file qgsrelationmanager.cpp.

◆ relation()

QgsRelation QgsRelationManager::relation ( const QString &  id) const

Get access to a relation by its id.

Parameters
idThe id to search for
Returns
A relation. Invalid if not found.
See also
relationsByName()

Definition at line 72 of file qgsrelationmanager.cpp.

◆ relations()

QMap< QString, QgsRelation > QgsRelationManager::relations ( ) const

Get access to the relations managed by this class.

Returns
A QMap where the key is the relation id, the value the relation object.

Definition at line 43 of file qgsrelationmanager.cpp.

◆ relationsByName()

QList< QgsRelation > QgsRelationManager::relationsByName ( const QString &  name) const

Returns a list of relations with matching names.

Parameters
namerelation name to search for. Searching is case insensitive.
Returns
a list of matching relations
Since
QGIS 2.16
See also
relation()

Definition at line 77 of file qgsrelationmanager.cpp.

◆ relationsLoaded

void QgsRelationManager::relationsLoaded ( )
signal

This signal is emitted when the relations were loaded after reading a project.

◆ removeRelation() [1/2]

void QgsRelationManager::removeRelation ( const QString &  id)

Remove a relation.

Parameters
idThe id of the relation to remove.

Definition at line 60 of file qgsrelationmanager.cpp.

◆ removeRelation() [2/2]

void QgsRelationManager::removeRelation ( const QgsRelation relation)

Remove a relation.

Parameters
relationThe relation to remove.

Definition at line 66 of file qgsrelationmanager.cpp.

◆ setRelations()

void QgsRelationManager::setRelations ( const QList< QgsRelation > &  relations)

Will set the specified relations and remove any relation currently set.

Parameters
relationsA list of relations to set.

Definition at line 33 of file qgsrelationmanager.cpp.


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