Class: QgsVectorDataProvider

class qgis.core.QgsVectorDataProvider

Bases: QgsDataProvider, QgsFeatureSink, QgsFeatureSource

This is the base class for vector data providers.

Data providers abstract the retrieval and writing (where supported) of feature and attribute information from a spatial datasource.

QgsVectorDataProvider(uri: str = ‘’, providerOptions: QgsDataProvider.ProviderOptions = QgsDataProvider.ProviderOptions(), flags: Union[QgsDataProvider.ReadFlags, QgsDataProvider.ReadFlag] = QgsDataProvider.ReadFlags()) Constructor for a vector data provider.

The uri argument specifies the uniform resource locator (URI) for the associated dataset.

Additional creation options are specified within the options value and since QGIS 3.16 creation flags are specified within the flags value.

Enums

FeatureCountState

Bases: enum.IntEnum

Methods

addAttributes

Adds new attributes to the provider.

addFeatures

param flist:

aggregate

Calculates an aggregated value from the layer's features.

appendError

Add error message

attributeEditCapabilities

Returns the provider's supported attribute editing capabilities.

attributeIndexes

Returns list of indexes to fetch all attributes in nextFeature()

availableEncodings

Returns a list of available encodings

cancelReload

Cancels the current reloading of data.

capabilities

Returns flags containing the supported capabilities note, some capabilities may change depending on whether a spatial filter is active on this provider, so it may be prudent to check this value per intended operation.

capabilitiesString

Returns the above in friendly format.

changeAttributeValues

Changes attribute values of existing features.

changeFeatures

Changes attribute values and geometries of existing features.

changeGeometryValues

Changes geometries of existing features

childEvent

clearErrors

Clear recorded errors

clearMinMaxCache

Invalidates the min/max cache.

connectNotify

convertToProviderType

Converts the geometry to the provider type if possible / necessary

convertValue

param type:

createAttributeIndex

Create an attribute index on the datasource

createLabeling

Creates labeling settings, using provider backend specific information.

createRenderer

Creates a new vector layer feature renderer, using provider backend specific information.

createSpatialIndex

Creates a spatial index on the datasource (if supported by the provider type).

customEvent

dataComment

Returns a short comment for the data that this provider is providing access to (e.g. the comment for postgres table).

defaultValue

Returns any literal default values which are present at the provider for a specified field index.

defaultValueClause

Returns any default value clauses which are present at the provider for a specified field index.

deleteAttributes

Deletes existing attributes from the provider.

deleteFeatures

Deletes one or more features from the provider.

dependencies

Gets the list of layer ids on which this layer depends.

disconnectNotify

discoverRelations

Discover the available relations with the given layers.

doesStrictFeatureTypeCheck

Returns True if the provider is strict about the type of inserted features (e.g. no multipolygon in a polygon layer).

elevationProperties

rtype:

QgsDataProviderElevationProperties

empty

Returns True if the layer does not contain any feature.

encoding

Returns the encoding which is used for accessing data.

enumValues

Returns the possible enum values of an attribute.

errors

Gets recorded errors

featureCount

Number of features in the layer

featureSource

Returns feature source object that can be used for querying provider's data.

fieldConstraints

Returns any constraints which are present at the provider for a specified field index.

fieldNameIndex

Returns the index of a field name or -1 if the field does not exist

fieldNameMap

Returns a map where the key is the name of the field and the value is its index

fields

Returns the fields associated with this data provider.

fillMinMaxCache

Populates the cache of minimum and maximum attribute values.

forceReload

getFeatures

Query the provider for features specified in request.

handlePostCloneOperations

Handles any post-clone operations required after this vector data provider was cloned from the source provider.

hasErrors

Provider has errors to report

hasFeatures

Will always return FeatureAvailability.FeaturesAvailable or FeatureAvailability.NoFeaturesAvailable.

hasMetadata

Returns True if the data source has metadata, False otherwise.

isSignalConnected

isSqlQuery

Returns True if the layer is a query (SQL) layer.

lastError

rtype:

str

maximumValue

Returns the maximum value of an attribute

metadata

Gets metadata, dependent on the provider type, that will be display in the metadata tab of the layer properties.

minimumValue

Returns the minimum value of an attribute

nativeTypes

Returns the names of the supported types

palAttributeIndexNames

Returns list of indexes to names for QgsPalLabeling fix

pkAttributeIndexes

Returns list of indexes of fields that make up the primary key

pushError

Push a notification about errors that happened in this providers scope.

receivers

renameAttributes

Renames existing attributes.

sender

senderSignalIndex

setEncoding

Set encoding used for accessing data from layer.

setError

Sets error message

setNativeTypes

Set the list of native types supported by this provider.

skipConstraintCheck

Returns True if a constraint check should be skipped for a specified field (e.g., if the value returned by defaultValue() is trusted implicitly.

sourceCrs

rtype:

QgsCoordinateReferenceSystem

sourceExtent

rtype:

QgsRectangle

sourceExtent3D

rtype:

QgsBox3D

sourceName

rtype:

str

storageType

Returns the permanent storage type for this layer as a friendly name.

supportedType

check if provider supports type of field

temporalCapabilities

rtype:

QgsVectorDataProviderTemporalCapabilities

textEncoding

Gets this providers encoding

timerEvent

transaction

Returns the transaction this data provider is included in, if any.

translateMetadataKey

Gets the translated metadata key.

translateMetadataValue

Gets the translated metadata value.

truncate

Removes all features from the layer.

uniqueStringsMatching

Returns unique string values of an attribute which contain a specified subset string.

vectorLayerTypeFlags

Returns the vector layer type flags.

wkbType

Returns the geometry type which is returned by this layer

Signals

raiseError

pyqtSignal(*types, name: str = ..., revision: int = ..., arguments: Sequence = ...) -> PYQT_SIGNAL

Attributes

AddAttributes

AddFeatures

CancelSupport

ChangeAttributeValues

ChangeFeatures

ChangeGeometries

CircularGeometries

CreateAttributeIndex

CreateLabeling

CreateRenderer

CreateSpatialIndex

DeleteAttributes

DeleteFeatures

EditingCapabilities

FastTruncate

FeatureSymbology

NoCapabilities

ReadLayerMetadata

ReloadData

RenameAttributes

SelectAtId

SelectEncoding

SimplifyGeometries

SimplifyGeometriesWithTopologicalValidation

TransactionSupport

WriteLayerMetadata

AddAttributes = 8
AddFeatures = 1
CancelSupport = 8388608
class Capabilities
class Capabilities(Union[QgsVectorDataProvider.Capabilities, QgsVectorDataProvider.Capability])
class Capabilities(QgsVectorDataProvider.Capabilities)

Bases: sip.wrapper

class Capability

Bases: int

ChangeAttributeValues = 4
ChangeFeatures = 262144
ChangeGeometries = 256
CircularGeometries = 131072
CreateAttributeIndex = 4096
CreateLabeling = 33554432
CreateRenderer = 16777216
CreateSpatialIndex = 64
DeleteAttributes = 16
DeleteFeatures = 2
EditingCapabilities = 524575
FastTruncate = 1048576
class FeatureCountState(value)

Bases: enum.IntEnum

Enumeration of feature count states

New in version 3.20.

  • Uncounted: Feature count not yet computed

  • UnknownCount: Provider returned an unknown feature count

baseClass

alias of Qgis

FeatureSymbology = 134217728
class NativeType(typeDesc: str, typeName: str, type: QVariant.Type, minLen: int = 0, maxLen: int = 0, minPrec: int = 0, maxPrec: int = 0, subType: QVariant.Type = QVariant.Invalid)
class NativeType(QgsVectorDataProvider.NativeType)

Bases: sip.wrapper

mMaxLen
mMaxPrec
mMinLen
mMinPrec
mSubType
mType
mTypeDesc
mTypeName
NoCapabilities = 0
ReadLayerMetadata = 2097152
ReloadData = 67108864
RenameAttributes = 524288
SelectAtId = 128
SelectEncoding = 8192
SimplifyGeometries = 16384
SimplifyGeometriesWithTopologicalValidation = 32768
TransactionSupport = 65536
WriteLayerMetadata = 4194304
addAttributes(self, attributes: object) bool

Adds new attributes to the provider. Returns True in case of success and False in case of failure. If attributes are added using this method then QgsVectorLayer.updateFields() must be called manually to ensure that the layer’s field are correctly reported.

Parameters:

attributes (object) –

Return type:

bool

addFeatures(self, flist: Iterable[QgsFeature], flags: QgsFeatureSink.Flags | QgsFeatureSink.Flag = QgsFeatureSink.Flags()) Tuple[bool, List[QgsFeature]]
Parameters:
Return type:

Tuple[bool, List[QgsFeature]]

aggregate(self, aggregate: Qgis.Aggregate, index: int, parameters: QgsAggregateCalculator.AggregateParameters, context: QgsExpressionContext, fids: object = None) Tuple[Any, bool]

Calculates an aggregated value from the layer’s features. The base implementation does nothing, but subclasses can override this method to handoff calculation of aggregates to the provider.

Parameters:
  • aggregate (Qgis.Aggregate) – aggregate to calculate

  • index (int) – the index of the attribute to calculate aggregate over

  • parameters (QgsAggregateCalculator.AggregateParameters) – parameters controlling aggregate calculation

  • context (QgsExpressionContext) – expression context for filter

  • ok – will be set to True if calculation was successfully performed by the data provider

  • fids (object = None) – list of fids to filter, otherwise will use all fids

Return type:

Tuple[Any, bool]

Returns:

calculated aggregate value

appendError(self, message: QgsErrorMessage)

Add error message

attributeEditCapabilities(self) Qgis.VectorDataProviderAttributeEditCapabilities

Returns the provider’s supported attribute editing capabilities.

See also

capabilities()

New in version 3.32.

Return type:

Qgis.VectorDataProviderAttributeEditCapabilities

attributeIndexes(self) List[int]

Returns list of indexes to fetch all attributes in nextFeature()

Return type:

List[int]

availableEncodings() List[str]

Returns a list of available encodings

Return type:

List[str]

cancelReload(self) bool

Cancels the current reloading of data.

Return type:

bool

Returns:

True if the reloading has been correctly interrupted, False otherwise

See also

reloadData()

New in version 3.2.

capabilities(self) QgsVectorDataProvider.Capabilities

Returns flags containing the supported capabilities note, some capabilities may change depending on whether a spatial filter is active on this provider, so it may be prudent to check this value per intended operation.

Return type:

QgsVectorDataProvider.Capabilities

capabilitiesString(self) str

Returns the above in friendly format.

Return type:

str

changeAttributeValues(self, attr_map: object) bool

Changes attribute values of existing features. This should succeed if the provider reports the ChangeAttributeValues capability. The method returns False if the provider does not have ChangeAttributeValues capability or if any of the changes could not be successfully applied.

Parameters:

attr_map (object) – a map containing changed attributes

Return type:

bool

Returns:

True in case of success and False in case of failure

changeFeatures(self, attr_map: object, geometry_map: object) bool

Changes attribute values and geometries of existing features. This should succeed if the provider reports both the ChangeAttributeValues and ChangeGeometries capabilities. Providers which report the ChangeFeatures capability implement an optimised version of this method.

Parameters:
  • attr_map (object) – a map containing changed attributes

  • geometry_map (object) – A QgsGeometryMap whose index contains the feature IDs that will have their geometries changed. The second map parameter being the new geometries themselves

Return type:

bool

Returns:

True in case of success and False in case of failure

changeGeometryValues(self, geometry_map: object) bool

Changes geometries of existing features

Parameters:

geometry_map (object) – A QgsGeometryMap whose index contains the feature IDs that will have their geometries changed. The second map parameter being the new geometries themselves

Return type:

bool

Returns:

True in case of success and False in case of failure

childEvent(self, QChildEvent)
clearErrors(self)

Clear recorded errors

clearMinMaxCache(self)

Invalidates the min/max cache. This will force the provider to recalculate the cache the next time it is requested.

connectNotify(self, QMetaMethod)
convertToProviderType(self, geom: QgsGeometry) QgsGeometry

Converts the geometry to the provider type if possible / necessary

Returns:

the converted geometry or None if no conversion was necessary or possible

Note

The default implementation simply calls the static version of this function.

convertToProviderType(geometry: QgsGeometry, providerGeometryType: Qgis.WkbType) -> QgsGeometry Converts the geometry to the provider geometry type providerGeometryType if possible / necessary

Return type:

QgsGeometry

Returns:

the converted geometry or None if no conversion was necessary or possible

New in version 3.34.

Parameters:

geom (QgsGeometry) –

convertValue(type: QVariant.Type, value: str) Any
Parameters:
  • type (QVariant.Type) –

  • value (str) –

Return type:

Any

createAttributeIndex(self, field: int) bool

Create an attribute index on the datasource

Parameters:

field (int) –

Return type:

bool

createLabeling(self, configuration: Dict[str, Any] = {}) QgsAbstractVectorLayerLabeling

Creates labeling settings, using provider backend specific information.

The configuration map can be used to pass provider-specific configuration maps to the provider to allow customization of the returned labeling object. Support and format of configuration varies by provider.

When called with an empty configuration map the provider’s default labeling settings will be returned.

This method returns a new labeling settings and the caller takes ownership of the returned object.

Only providers which report the CreateLabeling capability will return labeling settings. Other providers will return None.

New in version 3.6.

Parameters:

configuration (Dict[str) –

Return type:

QgsAbstractVectorLayerLabeling

createRenderer(self, configuration: Dict[str, Any] = {}) QgsFeatureRenderer

Creates a new vector layer feature renderer, using provider backend specific information.

The configuration map can be used to pass provider-specific configuration maps to the provider to allow customization of the returned renderer. Support and format of configuration varies by provider.

When called with an empty configuration map the provider’s default renderer will be returned.

This method returns a new renderer and the caller takes ownership of the returned object.

Only providers which report the CreateRenderer capability will return a feature renderer. Other providers will return None.

New in version 3.2.

Parameters:

configuration (Dict[str) –

Return type:

QgsFeatureRenderer

createSpatialIndex(self) bool

Creates a spatial index on the datasource (if supported by the provider type).

Return type:

bool

Returns:

True in case of success

customEvent(self, QEvent)
dataComment(self) str

Returns a short comment for the data that this provider is providing access to (e.g. the comment for postgres table).

Return type:

str

defaultValue(self, fieldIndex: int) Any

Returns any literal default values which are present at the provider for a specified field index. Important - this should ONLY be called when creating an attribute to insert directly into the database. Do not call this method for non-feature creation or modification, e.g., when validating an attribute or to compare it against an existing value, as calling it can cause changes to the underlying data source (e.g., Postgres provider where the default value is calculated as a result of a sequence). It is recommended that you instead use the methods in QgsVectorLayerUtils such as QgsVectorLayerUtils.createFeature() so that default value handling and validation is automatically carried out.

Parameters:

fieldIndex (int) –

Return type:

Any

defaultValueClause(self, fieldIndex: int) str

Returns any default value clauses which are present at the provider for a specified field index. These clauses are usually SQL fragments which must be evaluated by the provider, e.g., sequence values.

See also

defaultValue()

Parameters:

fieldIndex (int) –

Return type:

str

deleteAttributes(self, attributes: object) bool

Deletes existing attributes from the provider. If attributes are deleted using this method then QgsVectorLayer.updateFields() must be called manually to ensure that the layer’s field are correctly reported.

Parameters:

attributes (object) – a set containing indices of attributes

Return type:

bool

Returns:

True in case of success and False in case of failure

deleteFeatures(self, id: object) bool

Deletes one or more features from the provider. This requires the DeleteFeatures capability.

Parameters:

id (object) – list containing feature ids to delete

Return type:

bool

Returns:

True in case of success and False in case of failure

See also

truncate()

dependencies(self) Set[QgsMapLayerDependency]

Gets the list of layer ids on which this layer depends. This in particular determines the order of layer loading.

Return type:

Set[QgsMapLayerDependency]

disconnectNotify(self, QMetaMethod)
discoverRelations(self, target: QgsVectorLayer, layers: Iterable[QgsVectorLayer]) List[QgsRelation]

Discover the available relations with the given layers.

Parameters:
Return type:

List[QgsRelation]

Returns:

the list of N-1 relations from this provider.

doesStrictFeatureTypeCheck(self) bool

Returns True if the provider is strict about the type of inserted features (e.g. no multipolygon in a polygon layer)

Return type:

bool

elevationProperties(self) QgsDataProviderElevationProperties
Return type:

QgsDataProviderElevationProperties

empty(self) bool

Returns True if the layer does not contain any feature.

New in version 3.4.

Return type:

bool

encoding(self) str

Returns the encoding which is used for accessing data.

See also

setEncoding()

Return type:

str

enumValues(self, index: int) List[str]

Returns the possible enum values of an attribute. Returns an empty stringlist if a provider does not support enum types or if the given attribute is not an enum type.

Parameters:

index (int) – the index of the attribute

Return type:

List[str]

errors(self) List[str]

Gets recorded errors

Return type:

List[str]

featureCount(self) int

Number of features in the layer

Return type:

int

Returns:

number of features

featureSource(self) QgsAbstractFeatureSource

Returns feature source object that can be used for querying provider’s data. The returned feature source is independent from provider - any changes to provider’s state (e.g. change of subset string) will not be reflected in the feature source, therefore it can be safely used for processing in background without having to care about possible changes within provider that may happen concurrently. Also, even in the case of provider being deleted, any feature source obtained from the provider will be kept alive and working (they are independent and owned by the caller).

Sometimes there are cases when some data needs to be shared between vector data provider and its feature source. In such cases, the implementation must ensure that the data is not susceptible to run condition. For example, if it is possible that both feature source and provider may need reading/writing to some shared data at the same time, some synchronization mechanisms must be used (e.g. mutexes) to prevent data corruption.

Return type:

QgsAbstractFeatureSource

Returns:

new instance of QgsAbstractFeatureSource (caller is responsible for deleting it)

fieldConstraints(self, fieldIndex: int) QgsFieldConstraints.Constraints

Returns any constraints which are present at the provider for a specified field index.

Parameters:

fieldIndex (int) –

Return type:

QgsFieldConstraints.Constraints

fieldNameIndex(self, fieldName: str) int

Returns the index of a field name or -1 if the field does not exist

Parameters:

fieldName (str) –

Return type:

int

fieldNameMap(self) object

Returns a map where the key is the name of the field and the value is its index

Return type:

object

fields(self) QgsFields

Returns the fields associated with this data provider.

Return type:

QgsFields

fillMinMaxCache(self)

Populates the cache of minimum and maximum attribute values.

forceReload(self)

Deprecated since version QGIS: 3.12 - will be removed in QGIS 4.0 - use reloadData instead

getFeatures(self, request: QgsFeatureRequest = QgsFeatureRequest()) QgsFeatureIterator

Query the provider for features specified in request.

Parameters:

request (QgsFeatureRequest = QgsFeatureRequest()) – feature request describing parameters of features to return

Return type:

QgsFeatureIterator

Returns:

iterator for matching features from provider

handlePostCloneOperations(self, source: QgsVectorDataProvider)

Handles any post-clone operations required after this vector data provider was cloned from the source provider.

New in version 3.8.1.

Parameters:

source (QgsVectorDataProvider) –

hasErrors(self) bool

Provider has errors to report

Return type:

bool

hasFeatures(self) Qgis.FeatureAvailability

Will always return FeatureAvailability.FeaturesAvailable or FeatureAvailability.NoFeaturesAvailable.

Calls empty() internally. Providers should override empty() instead if they provide an optimized version of this call.

See also

empty()

New in version 3.4.

Return type:

Qgis.FeatureAvailability

hasMetadata(self) bool

Returns True if the data source has metadata, False otherwise.

Return type:

bool

Returns:

True if data source has metadata, False otherwise.

isSignalConnected(self, QMetaMethod) bool
isSqlQuery(self) bool

Returns True if the layer is a query (SQL) layer.

Note

this is simply a shortcut to check if the SqlQuery flag is set.

New in version 3.24.

Return type:

bool

lastError(self) str
Return type:

str

maximumValue(self, index: int) Any

Returns the maximum value of an attribute

Parameters:

index (int) – the index of the attribute

Default implementation walks all numeric attributes and caches minimal and maximal values. If provider has facilities to retrieve maximal value directly, override this function.

Return type:

Any

metadata(self) Dict[str, Any]

Gets metadata, dependent on the provider type, that will be display in the metadata tab of the layer properties.

Return type:

Dict[str, Any]

Returns:

The provider metadata

minimumValue(self, index: int) Any

Returns the minimum value of an attribute

Parameters:

index (int) – the index of the attribute

Default implementation walks all numeric attributes and caches minimal and maximal values. If provider has facilities to retrieve minimal value directly, override this function.

Return type:

Any

nativeTypes(self) List[QgsVectorDataProvider.NativeType]

Returns the names of the supported types

Return type:

List[QgsVectorDataProvider.NativeType]

palAttributeIndexNames(self) Dict[int, str]

Returns list of indexes to names for QgsPalLabeling fix

Deprecated since version QGIS: 3.32 this method is unused and will always return an empty hash

Return type:

Dict[int, str]

pkAttributeIndexes(self) List[int]

Returns list of indexes of fields that make up the primary key

Return type:

List[int]

pushError(self, msg: str)

Push a notification about errors that happened in this providers scope. Errors should be translated strings that require the users immediate attention.

For general debug information use QgsMessageLog.logMessage() instead.

Parameters:

msg (str) –

raiseError

pyqtSignal(*types, name: str = …, revision: int = …, arguments: Sequence = …) -> PYQT_SIGNAL

types is normally a sequence of individual types. Each type is either a type object or a string that is the name of a C++ type. Alternatively each type could itself be a sequence of types each describing a different overloaded signal. name is the optional C++ name of the signal. If it is not specified then the name of the class attribute that is bound to the signal is used. revision is the optional revision of the signal that is exported to QML. If it is not specified then 0 is used. arguments is the optional sequence of the names of the signal’s arguments.

Parameters:
  • name (str = ...) –

  • revision (int = ...) –

  • arguments (Sequence = ...) –

Return type:

PYQT_SIGNAL

receivers(self, PYQT_SIGNAL) int
renameAttributes(self, renamedAttributes: Dict[int, str]) bool

Renames existing attributes. If attributes are renamed using this method then QgsVectorLayer.updateFields() must be called manually to ensure that the layer’s field are correctly reported.

Parameters:

renamedAttributes (Dict[int) – map of attribute index to new attribute name

Return type:

bool

Returns:

True in case of success and False in case of failure

sender(self) QObject
senderSignalIndex(self) int
setEncoding(self, e: str)

Set encoding used for accessing data from layer.

An empty encoding string indicates that the provider should automatically select the most appropriate encoding for the data source.

Warning

Support for setting the provider encoding depends on the underlying data provider. Check capabilities() for the QgsVectorDataProvider.SelectEncoding capability in order to determine if the provider supports this ability.

See also

encoding()

Parameters:

e (str) –

setError(self, error: QgsError)

Sets error message

setNativeTypes(self, nativeTypes: Iterable[QgsVectorDataProvider.NativeType])

Set the list of native types supported by this provider. Usually done in the constructor.

Parameters:

nativeTypes (Iterable[QgsVectorDataProvider.NativeType]) –

skipConstraintCheck(self, fieldIndex: int, constraint: QgsFieldConstraints.Constraint, value: Any = None) bool

Returns True if a constraint check should be skipped for a specified field (e.g., if the value returned by defaultValue() is trusted implicitly. An optional attribute value can be passed which can help refine the skip constraint check.

Parameters:
Return type:

bool

sourceCrs(self) QgsCoordinateReferenceSystem
Return type:

QgsCoordinateReferenceSystem

sourceExtent(self) QgsRectangle
Return type:

QgsRectangle

sourceExtent3D(self) QgsBox3D
Return type:

QgsBox3D

sourceName(self) str
Return type:

str

storageType(self) str

Returns the permanent storage type for this layer as a friendly name.

Return type:

str

supportedType(self, field: QgsField) bool

check if provider supports type of field

Parameters:

field (QgsField) –

Return type:

bool

temporalCapabilities(self) QgsVectorDataProviderTemporalCapabilities
Return type:

QgsVectorDataProviderTemporalCapabilities

textEncoding(self) QTextCodec

Gets this providers encoding

Return type:

QTextCodec

timerEvent(self, QTimerEvent)
transaction(self) QgsTransaction

Returns the transaction this data provider is included in, if any.

Return type:

QgsTransaction

translateMetadataKey(self, mdKey: str) str

Gets the translated metadata key.

Parameters:

mdKey (str) – The metadata key

Return type:

str

Returns:

The translated metadata value

translateMetadataValue(self, mdKey: str, value: Any) str

Gets the translated metadata value.

Parameters:
  • mdKey (str) – The metadata key

  • value (Any) – The metadata value

Return type:

str

Returns:

The translated metadata value

truncate(self) bool

Removes all features from the layer. This requires either the FastTruncate or DeleteFeatures capability. Providers with the FastTruncate capability will use an optimised method to truncate the layer.

Return type:

bool

Returns:

True in case of success and False in case of failure.

See also

deleteFeatures()

uniqueStringsMatching(self, index: int, substring: str, limit: int = -1, feedback: QgsFeedback = None) List[str]

Returns unique string values of an attribute which contain a specified subset string. Subset matching is done in a case-insensitive manner.

Parameters:
  • index (int) – the index of the attribute

  • substring (str) – substring to match (case insensitive)

  • limit (int = -1) – maxmum number of the values to return, or -1 to return all unique values

  • feedback (QgsFeedback = None) – optional feedback object for canceling request

Return type:

List[str]

Returns:

list of unique strings containing substring

vectorLayerTypeFlags(self) Qgis.VectorLayerTypeFlags

Returns the vector layer type flags.

See also

isSqlQuery()

New in version 3.24.

Return type:

Qgis.VectorLayerTypeFlags

wkbType(self) Qgis.WkbType

Returns the geometry type which is returned by this layer

Return type:

Qgis.WkbType