Class: QgsVirtualLayerDefinition

class qgis.core.QgsVirtualLayerDefinition(filePath: str = '')

Bases: sip.wrapper

Constructor with an optional file path

QgsVirtualLayerDefinition(QgsVirtualLayerDefinition)

Class to manipulate the definition of a virtual layer

It is used to extract parameters from an initial virtual layer definition as well as to store the complete, expanded definition once types have been detected.

Parameters

filePath

class SourceLayer(name: str, ref: str)

Bases: sip.wrapper

Constructor variant to build a live layer reference

QgsVirtualLayerDefinition.SourceLayer(name: str, source: str, provider: str, encoding: str) Constructor variant to build a layer with a provider and a source

QgsVirtualLayerDefinition.SourceLayer(QgsVirtualLayerDefinition.SourceLayer)

A SourceLayer is either a reference to a live layer in the registry or all the parameters needed to load it (provider key, source, etc.)

Parameters
  • name (str) –

  • ref (str) –

encoding(self) → str

Optional encoding for the provider

Return type

str

isReferenced(self) → bool

Is it a live layer or not ?

Return type

bool

name(self) → str

Name of the layer

Return type

str

provider(self) → str

Provider key

Return type

str

reference(self) → str

The reference (id) of the live layer

Return type

str

source(self) → str

The source url used by the provider to build the layer

Return type

str

addSource(self, name: str, ref: str)

Add a live layer source layer

addSource(self, name: str, source: str, provider: str, encoding: str = ‘’) Add a layer with a source, a provider and an encoding

Parameters
  • name (str) –

  • ref (str) –

fields(self) → QgsFields

Gets field definitions

Return type

QgsFields

filePath(self) → str

Gets the file path. May be empty

Return type

str

fromUrl(url: QUrl) → QgsVirtualLayerDefinition

Constructor to build a definition from a QUrl The path part of the URL is extracted as well as the following optional keys: layer_ref=layer_id[:name] represents a live layer referenced by its ID. An optional name can be given layer=provider:source[:name[:encoding]] represents a layer given by its provider key, its source url (URL-encoded). An optional name and encoding can be given geometry=column_name[:type:srid] gives the definition of the geometry column. Type can be either a WKB type code or a string (point, linestring, etc.) srid is an integer uid=column_name is the name of a column with unique integer values. nogeometry is a flag to force the layer to be a non-geometry layer query=sql represents the SQL query. Must be URL-encoded field=column_name:[int|real|text] represents a field with its name and its type

Parameters

url (QUrl) –

Return type

QgsVirtualLayerDefinition

geometryField(self) → str

Gets the name of the geometry field. Empty if no geometry field

Return type

str

geometrySrid(self) → int

Gets the SRID of the geometry

Return type

int

geometryWkbType(self) → QgsWkbTypes.Type

Gets the type of the geometry QgsWkbTypes.NoGeometry to hide any geometry QgsWkbTypes.Unknown for unknown types

Return type

QgsWkbTypes.Type

hasDefinedGeometry(self) → bool

Convenient method to test if the geometry is defined (not NoGeometry and not Unknown)

Return type

bool

hasReferencedLayers(self) → bool

Convenience method to test whether the definition has referenced (live) layers

Return type

bool

hasSourceLayer(self, name: str) → bool

Convenience method to test if a given source layer is part of the definition

Parameters

name (str) –

Return type

bool

isLazy(self) → bool

Returns the lazy mode.

Return type

bool

Returns

True if the loading is delayed, False otherwise.

See also

setLazy()

New in version 3.2.

query(self) → str

Gets the SQL query

Return type

str

setFields(self, fields: QgsFields)

Sets field definitions

Parameters

fields (QgsFields) –

setFilePath(self, filePath: str)

Sets the file path

Parameters

filePath (str) –

setGeometryField(self, geometryField: str)

Sets the name of the geometry field

Parameters

geometryField (str) –

setGeometrySrid(self, srid: int)

Sets the SRID of the geometry

Parameters

srid (int) –

setGeometryWkbType(self, t: QgsWkbTypes.Type)

Sets the type of the geometry

Parameters

t (QgsWkbTypes.Type) –

setLazy(self, lazy: bool)

Sets the lazy mode. If lazy is True, then the loading is delayed until an explicit reloading of the layer.

Parameters

lazy (bool) – True to delay the loading, False otherwise

See also

isLazy()

New in version 3.2.

setQuery(self, query: str)

Sets the SQL query

Parameters

query (str) –

setUid(self, uid: str)

Sets the name of the field with unique identifiers

Parameters

uid (str) –

sourceLayers(self) → List[QgsVirtualLayerDefinition.SourceLayer]

Gets access to the source layers

Return type

List[QgsVirtualLayerDefinition.SourceLayer]

toString(self) → str

Convert into a QString that can be read by the virtual layer provider

Return type

str

toUrl(self) → QUrl

Convert the definition into a QUrl

Return type

QUrl

uid(self) → str

Gets the name of the field with unique identifiers

Return type

str