QGIS API Documentation  2.99.0-Master (ae4d26a)
qgsvectordataprovider.h
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1 /***************************************************************************
2  qgsvectordataprovider.h - DataProvider Interface for vector layers
3  --------------------------------------
4  Date : 23-Sep-2004
5  Copyright : (C) 2004 by Marco Hugentobler
6  email : [email protected]
7  ***************************************************************************
8  * *
9  * This program is free software; you can redistribute it and/or modify *
10  * it under the terms of the GNU General Public License as published by *
11  * the Free Software Foundation; either version 2 of the License, or *
12  * (at your option) any later version. *
13  * *
14  ***************************************************************************/
15 #ifndef QGSVECTORDATAPROVIDER_H
16 #define QGSVECTORDATAPROVIDER_H
17 
18 class QTextCodec;
19 
20 #include "qgis_core.h"
21 #include <QList>
22 #include <QSet>
23 #include <QMap>
24 #include <QHash>
25 
26 //QGIS Includes
27 #include "qgis.h"
28 #include "qgsdataprovider.h"
29 #include "qgsfeature.h"
30 #include "qgsaggregatecalculator.h"
31 #include "qgsmaplayerdependency.h"
32 #include "qgsrelation.h"
33 #include "qgsfeaturesink.h"
34 #include "qgsfeaturesource.h"
35 
36 typedef QList<int> QgsAttributeList SIP_SKIP;
37 typedef QSet<int> QgsAttributeIds SIP_SKIP;
38 typedef QHash<int, QString> QgsAttrPalIndexNameHash;
39 
40 class QgsFeatureIterator;
41 class QgsTransaction;
42 class QgsFeedback;
43 
44 #include "qgsfeaturerequest.h"
45 
55 class CORE_EXPORT QgsVectorDataProvider : public QgsDataProvider, public QgsFeatureSink, public QgsFeatureSource
56 {
57  Q_OBJECT
58 
59  friend class QgsTransaction;
61 
62  public:
63 
64  // If you add to this, please also add to capabilitiesString()
65 
70  {
71  NoCapabilities = 0,
72  AddFeatures = 1,
73  DeleteFeatures = 1 << 1,
74  ChangeAttributeValues = 1 << 2,
75  AddAttributes = 1 << 3,
76  DeleteAttributes = 1 << 4,
77  CreateSpatialIndex = 1 << 6,
78  SelectAtId = 1 << 7,
79  ChangeGeometries = 1 << 8,
80  SelectEncoding = 1 << 13,
81  CreateAttributeIndex = 1 << 12,
82  SimplifyGeometries = 1 << 14,
83  SimplifyGeometriesWithTopologicalValidation = 1 << 15,
84  TransactionSupport = 1 << 16,
85  CircularGeometries = 1 << 17,
86  ChangeFeatures = 1 << 18,
89  RenameAttributes = 1 << 19,
90  FastTruncate = 1 << 20,
91  };
92 
93  Q_DECLARE_FLAGS( Capabilities, Capability )
94 
95 
96  static const int EditingCapabilities = AddFeatures | DeleteFeatures |
97  ChangeAttributeValues | ChangeGeometries | AddAttributes | DeleteAttributes |
98  RenameAttributes;
99 
104  {
106  Uncounted = -2,
108  UnknownCount = -1,
109  };
110 
115  QgsVectorDataProvider( const QString &uri = QString() );
116 
133  virtual QgsAbstractFeatureSource *featureSource() const = 0 SIP_FACTORY;
134 
138  virtual QString storageType() const;
139 
145  virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest &request = QgsFeatureRequest() ) const override = 0;
146 
150  virtual QgsWkbTypes::Type wkbType() const override = 0;
151 
156  virtual long featureCount() const override = 0;
157 
161  virtual QgsFields fields() const override = 0;
162 
163  QgsCoordinateReferenceSystem sourceCrs() const override;
164  QgsRectangle sourceExtent() const override;
165  QString sourceName() const override { return QString(); }
166 
171  virtual QString dataComment() const;
172 
181  virtual QVariant minimumValue( int index ) const override;
182 
191  virtual QVariant maximumValue( int index ) const override;
192 
202  virtual QStringList uniqueStringsMatching( int index, const QString &substring, int limit = -1,
203  QgsFeedback *feedback = nullptr ) const;
204 
216  virtual QVariant aggregate( QgsAggregateCalculator::Aggregate aggregate,
217  int index,
219  QgsExpressionContext *context,
220  bool &ok ) const;
221 
228  virtual void enumValues( int index, QStringList &enumList SIP_OUT ) const { Q_UNUSED( index ); enumList.clear(); }
229 
230  virtual bool addFeatures( QgsFeatureList &flist SIP_INOUT, QgsFeatureSink::Flags flags = 0 ) override;
231 
238  virtual bool deleteFeatures( const QgsFeatureIds &id );
239 
247  virtual bool truncate();
248 
254  virtual bool addAttributes( const QList<QgsField> &attributes );
255 
263  virtual bool deleteAttributes( const QgsAttributeIds &attributes );
264 
273  virtual bool renameAttributes( const QgsFieldNameMap &renamedAttributes );
274 
281  virtual bool changeAttributeValues( const QgsChangedAttributesMap &attr_map );
282 
294  virtual bool changeFeatures( const QgsChangedAttributesMap &attr_map,
295  const QgsGeometryMap &geometry_map );
296 
308  virtual QVariant defaultValue( int fieldIndex ) const;
309 
317  virtual QString defaultValueClause( int fieldIndex ) const;
318 
325  QgsFieldConstraints::Constraints fieldConstraints( int fieldIndex ) const;
326 
334  virtual bool skipConstraintCheck( int fieldIndex, QgsFieldConstraints::Constraint constraint, const QVariant &value = QVariant() ) const;
335 
343  virtual bool changeGeometryValues( const QgsGeometryMap &geometry_map );
344 
349  virtual bool createSpatialIndex();
350 
352  virtual bool createAttributeIndex( int field );
353 
360  virtual QgsVectorDataProvider::Capabilities capabilities() const;
361 
365  QString capabilitiesString() const;
366 
370  virtual void setEncoding( const QString &e );
371 
375  QString encoding() const;
376 
380  int fieldNameIndex( const QString &fieldName ) const;
381 
385  QMap<QString, int> fieldNameMap() const;
386 
390  virtual QgsAttributeList attributeIndexes() const;
391 
395  virtual QgsAttributeList pkAttributeIndexes() const;
396 
400  virtual QgsAttrPalIndexNameHash palAttributeIndexNames() const;
401 
405  bool supportedType( const QgsField &field ) const;
406 
407  struct NativeType
408  {
409  NativeType( const QString &typeDesc, const QString &typeName, QVariant::Type type, int minLen = 0, int maxLen = 0, int minPrec = 0, int maxPrec = 0, QVariant::Type subType = QVariant::Invalid )
410  : mTypeDesc( typeDesc )
411  , mTypeName( typeName )
412  , mType( type )
413  , mMinLen( minLen )
414  , mMaxLen( maxLen )
415  , mMinPrec( minPrec )
416  , mMaxPrec( maxPrec )
417  , mSubType( subType )
418  {}
419 
420  QString mTypeDesc;
421  QString mTypeName;
422  QVariant::Type mType;
423  int mMinLen;
424  int mMaxLen;
425  int mMinPrec;
426  int mMaxPrec;
427  QVariant::Type mSubType;
428  };
429 
433  QList< QgsVectorDataProvider::NativeType > nativeTypes() const;
434 
439  virtual bool doesStrictFeatureTypeCheck() const { return true; }
440 
442  static QStringList availableEncodings();
443 
447  bool hasErrors() const;
448 
452  void clearErrors();
453 
457  QStringList errors() const;
458 
463  virtual bool isSaveAndLoadStyleToDatabaseSupported() const;
464 
469  virtual bool isDeleteStyleFromDatabaseSupported() const;
470 
471  static QVariant convertValue( QVariant::Type type, const QString &value );
472 
476  virtual QgsTransaction *transaction() const;
477 
485  virtual void forceReload();
486 
490  virtual QSet<QgsMapLayerDependency> dependencies() const;
491 
499  virtual QList<QgsRelation> discoverRelations( const QgsVectorLayer *self, const QList<QgsVectorLayer *> &layers ) const;
500 
505  virtual QVariantMap metadata() const { return QVariantMap(); }
506 
512  virtual QString translateMetadataKey( const QString &mdKey ) const { return mdKey; }
513 
520  virtual QString translateMetadataValue( const QString &mdKey, const QVariant &value ) const { Q_UNUSED( mdKey ); return value.toString(); }
521 
529  virtual bool hasMetadata() const { return true; }
530 
531  signals:
532 
538  void raiseError( const QString &msg ) const;
539 
540  protected:
541 
546  void clearMinMaxCache();
547 
551  void fillMinMaxCache() const;
552 
562  void pushError( const QString &msg ) const;
563 
568  QgsGeometry convertToProviderType( const QgsGeometry &geom ) const;
569 
576  void setNativeTypes( const QList<QgsVectorDataProvider::NativeType> &nativeTypes );
577 
583  QTextCodec *textEncoding() const;
584 
585  private:
586  mutable bool mCacheMinMaxDirty = true;
587  mutable QMap<int, QVariant> mCacheMinValues, mCacheMaxValues;
588 
590  QTextCodec *mEncoding = nullptr;
591 
593  QgsAttributeList mAttributesToFetch;
594 
596  QList< NativeType > mNativeTypes;
597 
599  QMap<QString, QVariant::Type> mOldTypeList;
600 
602  mutable QStringList mErrors;
603 
604  static QStringList sEncodings;
605 
609  virtual void setTransaction( QgsTransaction * /*transaction*/ ) {}
610 
611 };
612 
613 Q_DECLARE_OPERATORS_FOR_FLAGS( QgsVectorDataProvider::Capabilities )
614 
615 #endif
Wrapper for iterator of features from vector data provider or vector layer.
QMap< QgsFeatureId, QgsGeometry > QgsGeometryMap
Definition: qgsfeature.h:537
virtual QgsRectangle sourceExtent() const
Returns the extent of all geometries from the source.
A rectangle specified with double values.
Definition: qgsrectangle.h:39
virtual QgsFields fields() const =0
Returns the fields associated with features in the source.
virtual bool addFeatures(QgsFeatureList &features)
Insert a copy of the given features into the layer (but does not commit it)
Constraint
Constraints which may be present on a field.
QSet< QgsFeatureId > QgsFeatureIds
Definition: qgsfeature.h:544
QList< QgsFeature > QgsFeatureList
Definition: qgsfeature.h:549
virtual QgsWkbTypes::Type wkbType() const =0
Returns the geometry type for features returned by this source.
An interface for objects which accept features via addFeature(s) methods.
Container of fields for a vector layer.
Definition: qgsfields.h:42
A geometry is the spatial representation of a feature.
Definition: qgsgeometry.h:94
Abstract base class for spatial data provider implementations.
#define SIP_INOUT
Definition: qgis_sip.h:64
virtual QString translateMetadataValue(const QString &mdKey, const QVariant &value) const
Get the translated metadata value.
Base class for feedback objects to be used for cancelation of something running in a worker thread...
Definition: qgsfeedback.h:44
virtual bool doesStrictFeatureTypeCheck() const
Returns true if the provider is strict about the type of inserted features (e.g.
QSet< int > QgsAttributeIds
Type
The WKB type describes the number of dimensions a geometry has.
Definition: qgswkbtypes.h:67
virtual QVariant minimumValue(int fieldIndex) const
Returns the minimum value for an attribute column or an invalid variant in case of error...
QString sourceName() const override
Returns a friendly display name for the source.
#define SIP_SKIP
Definition: qgis_sip.h:119
NativeType(const QString &typeDesc, const QString &typeName, QVariant::Type type, int minLen=0, int maxLen=0, int minPrec=0, int maxPrec=0, QVariant::Type subType=QVariant::Invalid)
Expression contexts are used to encapsulate the parameters around which a QgsExpression should be eva...
virtual QString translateMetadataKey(const QString &mdKey) const
Get the translated metadata key.
Capability
enumeration with capabilities that providers might implement
This class wraps a request for features to a vector layer (or directly its vector data provider)...
virtual bool deleteFeatures(const QgsFeatureIds &fid)
Deletes a set of features from the layer (but does not commit it)
#define SIP_FACTORY
Definition: qgis_sip.h:69
Encapsulate a field in an attribute table or data source.
Definition: qgsfield.h:48
Base class that can be used for any class that is capable of returning features.
QMap< int, QString > QgsFieldNameMap
Definition: qgsattributes.h:45
virtual QgsCoordinateReferenceSystem sourceCrs() const =0
Returns the coordinate reference system for features in the source.
QMap< QgsFeatureId, QgsAttributeMap > QgsChangedAttributesMap
Definition: qgsfeature.h:528
An interface for objects which provide features via a getFeatures method.
This class allows including a set of layers in a database-side transaction, provided the layer data p...
#define SIP_OUT
Definition: qgis_sip.h:51
This class represents a coordinate reference system (CRS).
virtual QVariant maximumValue(int fieldIndex) const
Returns the maximum value for an attribute column or an invalid variant in case of error...
virtual void enumValues(int index, QStringList &enumList) const
Returns the possible enum values of an attribute.
QList< int > QgsAttributeList
Definition: qgsfield.h:27
This is the base class for vector data providers.
Represents a vector layer which manages a vector based data sets.
QHash< int, QString > QgsAttrPalIndexNameHash
virtual bool hasMetadata() const
Returns true if the data source has metadata, false otherwise.
Aggregate
Available aggregates to calculate.
virtual QgsFeatureIterator getFeatures(const QgsFeatureRequest &request=QgsFeatureRequest()) const =0
Returns an iterator for the features in the source.
A bundle of parameters controlling aggregate calculation.
FeatureCountState
Enumeration of feature count states.
virtual long featureCount() const =0
Returns the number of features contained in the source, or -1 if the feature count is unknown...
virtual QVariantMap metadata() const
Get metadata, dependent on the provider type, that will be display in the metadata tab of the layer p...