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113 lines
3.4 KiB
Plaintext
113 lines
3.4 KiB
Plaintext
/**
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* This class manages a set of relations between layers.
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*/
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class QgsRelationManager : QObject
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{
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%TypeHeaderCode
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#include "qgsrelationmanager.h"
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%End
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public:
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/** Constructor for QgsRelationManager.
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* @param project associated project (used to notify project of changes)
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*/
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explicit QgsRelationManager( QgsProject *project = 0 );
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/**
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* Will set the specified relations and remove any relation currently set.
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*
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* @param relations A list of relations to set.
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*/
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void setRelations( const QList<QgsRelation> &relations );
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/**
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* Get access to the relations managed by this class.
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*
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* @return A QMap where the key is the relation id, the value the relation object.
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*/
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QMap<QString, QgsRelation> relations() const;
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/**
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* Add a relation.
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*
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* @param relation The relation to add.
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*/
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void addRelation( const QgsRelation &relation );
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/**
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* Remove a relation.
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*
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* @param id The id of the relation to remove.
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*/
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void removeRelation( const QString &id );
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/**
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* Remove a relation.
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*
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* @param relation The relation to remove.
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*/
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void removeRelation( const QgsRelation &relation );
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/**
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* Get access to a relation by its id.
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*
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* @param id The id to search for
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*
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* @return A relation. Invalid if not found.
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* @see relationsByName()
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*/
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QgsRelation relation( const QString &id ) const;
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/** Returns a list of relations with matching names.
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* @param name relation name to search for. Searching is case insensitive.
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* @returns a list of matching relations
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* @note added in QGIS 2.16
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* @see relation()
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*/
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QList<QgsRelation> relationsByName( const QString &name ) const;
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/**
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* Remove any relation managed by this class.
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*/
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void clear();
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/**
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* Get all relations where the specified layer (and field) is the referencing part (i.e. the child table with the foreign key).
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*
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* @param layer The layer which should be searched for.
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* @param fieldIdx The field which should be part of the foreign key. If not set will return all relations.
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*
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* @return A list of relations matching the given layer and fieldIdx.
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*/
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QList<QgsRelation> referencingRelations( const QgsVectorLayer *layer = 0, int fieldIdx = -2 ) const;
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/**
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* Get all relations where this layer is the referenced part (i.e. the parent table with the primary key being referenced from another layer).
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*
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* @param layer The layer which should be searched for.
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*
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* @return A list of relations where the specified layer is the referenced part.
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*/
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QList<QgsRelation> referencedRelations( QgsVectorLayer *layer = 0 ) const;
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/**
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* Discover all the relations available from the current layers.
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*
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* @param existingRelations the existing relations to filter them out
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* @param layers the current layers
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* @return the list of discovered relations
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* @note added in QGIS 3.0
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*/
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static QList<QgsRelation> discoverRelations( const QList<QgsRelation> &existingRelations, const QList<QgsVectorLayer*> &layers );
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signals:
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/** This signal is emitted when the relations were loaded after reading a project */
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void relationsLoaded();
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/**
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* Emitted when relations are added or removed to the manager.
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* @note added in QGIS 2.5
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*/
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void changed();
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};
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