Class: QgsDataProvider¶

class qgis.core.QgsDataProvider¶

Bases: PyQt5.QtCore.QObject

Abstract base class for spatial data provider implementations.

QgsDataProvider(uri: str = ‘’, providerOptions: QgsDataProvider.ProviderOptions = QgsDataProvider.ProviderOptions(), flags: Union[QgsDataProvider.ReadFlags, QgsDataProvider.ReadFlag] = QgsDataProvider.ReadFlags()) Create a new dataprovider with the specified in the uri.

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

Methods

appendError

Add error message

childEvent

connectNotify

crs

Returns the coordinate system for the data source.

customEvent

dataComment

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

dataSourceUri

Gets the data source specification.

dataTimestamp

Current time stamp of data source

description

Returns description

disconnectNotify

enterUpdateMode

Enter update mode.

error

Gets current status error.

extent

Returns the extent of the layer

fileRasterFilters

Returns raster file filter string

fileVectorFilters

Returns vector file filter string

flags

Returns the generic data provider flags.

invalidateConnections

Invalidate connections corresponding to specified name

isSignalConnected

isValid

Returns True if this is a valid layer.

layerMetadata

Returns layer metadata collected from the provider's source.

leaveUpdateMode

Leave update mode.

name

Returns a provider name

providerProperty

Gets the current value of a certain provider property.

receivers

reloadData

Reloads the data from the source for providers with data caches to synchronize, changes in the data source, feature counts and other specific actions.

sender

senderSignalIndex

setDataSourceUri

Set the data source specification.

setError

Sets error message

setLayerOrder

Reorder the list of layer names to be rendered by this provider (in order from bottom to top)

setListening

Set whether the provider will listen to datasource notifications If set, the provider will issue notify signals.

setProviderProperty

Allows setting arbitrary properties on the provider.

setSubLayerVisibility

Set the visibility of the given sublayer name

setSubsetString

Set the subset string used to create a subset of features in the layer.

setUri

Set the data source specification.

subLayerCount

Returns the number of layers for the current data source

subLayerStyles

Sub-layer styles for each sub-layer handled by this provider, in order from bottom to top

subLayers

Sub-layers handled by this provider, in order from bottom to top

sublayerSeparator

String sequence used for separating components of sublayers strings.

subsetString

Returns the subset definition string (typically sql) currently in use by the layer and used by the provider to limit the feature set.

supportsSubsetString

Returns True if the provider supports setting of subset strings.

temporalCapabilities

Returns the provider's temporal capabilities.

timerEvent

timestamp

Time stamp of data source in the moment when data/metadata were loaded by provider

updateExtents

Update the extents of the layer.

uri

Gets the data source specification.

writeLayerMetadata

Writes layer metadata to the underlying provider source.

Signals

dataChanged

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

fullExtentCalculated

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

notify

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

Attributes

CustomData

Database

Dir

EvaluateDefaultValues

File

FlagLoadDefaultStyle

FlagTrustDataSource

ForceReadOnly

Net

NoDataCapabilities

SUBLAYER_SEPARATOR

SkipFeatureCount

SkipFullScan

SkipGetExtent

CustomData = 3000¶

class DataCapabilities¶
class DataCapabilities(Union[QgsDataProvider.DataCapabilities, QgsDataProvider.DataCapability])
class DataCapabilities(QgsDataProvider.DataCapabilities): Bases: sip.wrapper

class DataCapability¶: Bases: int

Database = 4¶

Dir = 2¶

EvaluateDefaultValues = 0¶

File = 1¶

FlagLoadDefaultStyle = 4¶

FlagTrustDataSource = 1¶

ForceReadOnly = 32¶

Net = 8¶

NoDataCapabilities = 0¶

class ProviderOptions¶

class ProviderOptions(QgsDataProvider.ProviderOptions)

Bases: sip.wrapper

transformContext¶

class ProviderProperty¶: Bases: int

class ReadFlag¶: Bases: int

class ReadFlags¶
class ReadFlags(Union[QgsDataProvider.ReadFlags, QgsDataProvider.ReadFlag])
class ReadFlags(QgsDataProvider.ReadFlags): Bases: sip.wrapper

SUBLAYER_SEPARATOR = '!!::!!'¶

SkipFeatureCount = 2¶

SkipFullScan = 16¶

SkipGetExtent = 8¶

appendError(self, message: QgsErrorMessage)¶

Add error message

Parameters:: message (QgsErrorMessage) –

childEvent(self, QChildEvent)¶

connectNotify(self, QMetaMethod)¶

crs(self) → QgsCoordinateReferenceSystem¶

Returns the coordinate system for the data source. If the provider isn’t capable of returning its projection then an invalid QgsCoordinateReferenceSystem will be returned.

Return type:: QgsCoordinateReferenceSystem

customEvent(self, QEvent)¶

dataChanged¶

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

dataComment(self) → str¶

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

Note

The default implementation returns an empty string.

New in version 3.14.

Return type:: str

dataSourceUri(self, expandAuthConfig: bool = False) → str¶

Gets the data source specification. This may be a path or database connection string

Parameters:: expandAuthConfig (bool = False) – Whether to expand any assigned authentication configuration
Return type:: str
Returns:: data source specification

Note

The default authentication configuration expansion is False. This keeps credentials out of layer data source URIs and project files. Expansion should be specifically done only when needed within a provider

dataTimestamp(self) → QDateTime¶

Current time stamp of data source

Return type:: QDateTime

description(self) → str¶

Returns description

Returns a terse string describing what the provider is.

note

Instead of being pure virtual, might be better to generalize this behavior and presume that none of the sub-classes are going to do anything strange with regards to their name or description?

Return type:: str

disconnectNotify(self, QMetaMethod)¶

enterUpdateMode(self) → bool¶

Enter update mode.

This is aimed at providers that can open differently the connection to the datasource, according it to be in update mode or in read-only mode. A call to this method shall be balanced with a call to leaveUpdateMode(), if this method returns True.

Most providers will have an empty implementation for that method.

For backward compatibility, providers that implement enterUpdateMode() should still make sure to allow editing operations to work even if enterUpdateMode() is not explicitly called.

Several successive calls to enterUpdateMode() can be done. So there is a concept of stack of calls that must be handled by the provider. Only the first call to enterUpdateMode() will really turn update mode on.

Return type:: bool
Returns:: True in case of success (or no-op implementation), False in case of failure.

New in version 2.16.

error(self) → QgsError¶

Gets current status error. This error describes some principal problem for which provider cannot work and thus is not valid. It is not last error after accessing data by block(), identify() etc.

Return type:: QgsError

extent(self) → QgsRectangle¶

Returns the extent of the layer

Return type:: QgsRectangle
Returns:: QgsRectangle containing the extent of the layer

fileRasterFilters(self) → str¶

Returns raster file filter string

Returns a string suitable for a QFileDialog of raster file formats supported by the data provider. Naturally this will be an empty string for those data providers that do not deal with plain files, such as databases and servers.

Note

It’d be nice to eventually be raster/vector neutral.

Return type:: str

fileVectorFilters(self) → str¶

Returns vector file filter string

Returns a string suitable for a QFileDialog of vector file formats supported by the data provider. Naturally this will be an empty string for those data providers that do not deal with plain files, such as databases and servers.

Note

It’d be nice to eventually be raster/vector neutral.

Return type:: str

flags(self) → Qgis.DataProviderFlags¶

Returns the generic data provider flags.

New in version 3.26.

Return type:: Qgis.DataProviderFlags

fullExtentCalculated¶

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

invalidateConnections(self, connection: str)¶

Invalidate connections corresponding to specified name

New in version 2.16.

Parameters:: connection (str) –

isSignalConnected(self, QMetaMethod) → bool¶

isValid(self) → bool¶

Returns True if this is a valid layer. It is up to individual providers to determine what constitutes a valid layer.

Return type:: bool

layerMetadata(self) → QgsLayerMetadata¶

Returns layer metadata collected from the provider’s source.

Individual data providers must implement this method if they support collecting metadata.

See also

writeLayerMetadata()

New in version 3.0.

Return type:: QgsLayerMetadata

leaveUpdateMode(self) → bool¶

Leave update mode.

This is aimed at providers that can open differently the connection to the datasource, according it to be in update mode or in read-only mode. This method shall be balanced with a successful call to enterUpdateMode().

Most providers will have an empty implementation for that method.

Several successive calls to enterUpdateMode() can be done. So there is a concept of stack of calls that must be handled by the provider. Only the last call to leaveUpdateMode() will really turn update mode off.

Return type:: bool
Returns:: True in case of success (or no-op implementation), False in case of failure.

New in version 2.16.

name(self) → str¶

Returns a provider name

Essentially just returns the provider key. Should be used to build file dialogs so that providers can be shown with their supported types. Thus if more than one provider supports a given format, the user is able to select a specific provider to open that file.

note

Instead of being pure virtual, might be better to generalize this behavior and presume that none of the sub-classes are going to do anything strange with regards to their name or description?

Return type:: str

notify¶

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

providerProperty(self, property: QgsDataProvider.ProviderProperty, defaultValue: Any = None) → Any¶

Gets the current value of a certain provider property. It depends on the provider which properties are supported.

New in version 2.16.

Parameters:

property (QgsDataProvider.ProviderProperty) –
defaultValue (Any = None) –

Return type:

Any

receivers(self, PYQT_SIGNAL) → int¶

reloadData(self)¶: Reloads the data from the source for providers with data caches to synchronize, changes in the data source, feature counts and other specific actions. Emits the dataChanged signal

Note

only available for providers which implement the reloadProviderData() method.

sender(self) → QObject¶

senderSignalIndex(self) → int¶

setDataSourceUri(self, uri: str)¶

Set the data source specification. This may be a path or database connection string

Parameters:: uri (str) – source specification

setError(self, error: QgsError)¶

Sets error message

Parameters:: error (QgsError) –

setLayerOrder(self, layers: Iterable[str])¶

Reorder the list of layer names to be rendered by this provider (in order from bottom to top)

Note

layers must have been previously added.

Parameters:: layers (Iterable[str]) –

setListening(self, isListening: bool)¶

Set whether the provider will listen to datasource notifications If set, the provider will issue notify signals.

The default implementation does nothing.

See also

notify()

New in version 3.0.

Parameters:: isListening (bool) –

setProviderProperty(self, property: QgsDataProvider.ProviderProperty, value: Any)¶

Allows setting arbitrary properties on the provider. It depends on the provider which properties are supported.

New in version 2.16.

Parameters:

property (QgsDataProvider.ProviderProperty) –
value (Any) –

setSubLayerVisibility(self, name: str, vis: bool)¶

Set the visibility of the given sublayer name

Parameters:

name (str) –
vis (bool) –

setSubsetString(self, subset: str, updateFeatureCount: bool = True) → bool¶

Set the subset string used to create a subset of features in the layer. This may be a sql where clause or any other string that can be used by the data provider to create a subset. Must be implemented in the dataprovider.

Parameters:

subset (str) –
updateFeatureCount (bool = True) –

Return type:

bool

setUri(self, uri: QgsDataSourceUri)¶

Set the data source specification.

New in version 3.0.

Parameters:: uri (QgsDataSourceUri) –

subLayerCount(self) → int¶

Returns the number of layers for the current data source

Return type:: int

subLayerStyles(self) → List[str]¶

Sub-layer styles for each sub-layer handled by this provider, in order from bottom to top

Sub-layer styles are used to abstract the way the provider’s source can symbolise layers in some way at the server, before it serves them to the provider.

Return type:: List[str]

subLayers(self) → List[str]¶

Sub-layers handled by this provider, in order from bottom to top

Sub-layers are used when the provider’s source can combine layers it knows about in some way before it hands them off to the provider.

See also

SUBLAYER_SEPARATOR

Return type:: List[str]

sublayerSeparator() → str¶

String sequence used for separating components of sublayers strings.

Note

Replaces the static const SUBLAYER_SEPARATOR

See also

subLayers()

New in version 3.12.

Return type:: str

subsetString(self) → str¶

Returns the subset definition string (typically sql) currently in use by the layer and used by the provider to limit the feature set. Must be overridden in the dataprovider, otherwise returns a null QString.

Return type:: str

supportsSubsetString(self) → bool¶

Returns True if the provider supports setting of subset strings.

Return type:: bool

temporalCapabilities(self) → QgsDataProviderTemporalCapabilities¶

Returns the provider’s temporal capabilities.

This may be None, depending on the data provider.

New in version 3.14.

Return type:: QgsDataProviderTemporalCapabilities

timerEvent(self, QTimerEvent)¶

timestamp(self) → QDateTime¶

Time stamp of data source in the moment when data/metadata were loaded by provider

Return type:: QDateTime

updateExtents(self)¶: Update the extents of the layer. Not implemented by default.

uri(self) → QgsDataSourceUri¶

Gets the data source specification.

New in version 3.0.

Return type:: QgsDataSourceUri

writeLayerMetadata(self, metadata: QgsLayerMetadata) → bool¶

Writes layer metadata to the underlying provider source. Support depends on individual provider capabilities.

Returns True if metadata was successfully written to the data provider.

See also

layerMetadata()

New in version 3.0.

Parameters:: metadata (QgsLayerMetadata) –
Return type:: bool