Class: QgsVirtualLayerDefinition¶

Manipulates 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.

class qgis.core.QgsVirtualLayerDefinition[source]¶

Bases: object

__init__(filePath: str | None = '')

Constructor with an optional file path

Parameters:: filePath (Optional[str] = '')

__init__(a0: QgsVirtualLayerDefinition)

Parameters:: a0 (QgsVirtualLayerDefinition)

class SourceLayer[source]¶

Bases: object

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

QgsVirtualLayerDefinition.SourceLayer(name: Optional[str], ref: Optional[str]) Constructor variant to build a live layer reference

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

QgsVirtualLayerDefinition.SourceLayer(a0: QgsVirtualLayerDefinition.SourceLayer)

encoding(self) → str[source]¶

Optional encoding for the provider

Return type:: str

isReferenced(self) → bool[source]¶

Is it a live layer or not ?

Return type:: bool

name(self) → str[source]¶

Name of the layer

Return type:: str

provider(self) → str[source]¶

Provider key

Return type:: str

reference(self) → str[source]¶

The reference (id) of the live layer

Return type:: str

source(self) → str[source]¶

The source url used by the provider to build the layer

Return type:: str

addSource(self, name: str | None, ref: str | None)[source]¶

Add a live layer source layer

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

Parameters:

name (Optional[str])
ref (Optional[str])

fields(self) → QgsFields[source]¶

Gets field definitions

Return type:: QgsFields

filePath(self) → str[source]¶

Gets the file path. May be empty

Return type:: str

static fromUrl(url: QUrl) → QgsVirtualLayerDefinition[source]¶

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 subsetstring=subset_string represents the subsetstring

Parameters:: url (QUrl)
Return type:: QgsVirtualLayerDefinition

geometryField(self) → str[source]¶

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

Return type:: str

geometrySrid(self) → int[source]¶

Gets the SRID of the geometry

Return type:: int

geometryWkbType(self) → Qgis.WkbType[source]¶

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

Return type:: Qgis.WkbType

hasDefinedGeometry(self) → bool[source]¶

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

Return type:: bool

hasReferencedLayers(self) → bool[source]¶

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

Return type:: bool

hasSourceLayer(self, name: str | None) → bool[source]¶

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

Parameters:: name (Optional[str])
Return type:: bool

isLazy(self) → bool[source]¶

Returns the lazy mode.

Return type:: bool
Returns:: True if the loading is delayed, False otherwise.