Subgroup: Virtual

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.

Methods

addSource Add a live layer source layer
fields Get field definitions
filePath Get the file path.
fromUrl 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.
geometryField Get the name of the geometry field.
geometrySrid Get the SRID of the geometry
geometryWkbType Get the type of the geometry QgsWkbTypes.
hasDefinedGeometry Convenient method to test if the geometry is defined (not NoGeometry and not Unknown)
hasReferencedLayers Convenience method to test whether the definition has referenced (live) layers
hasSourceLayer Convenience method to test if a given source layer is part of the definition
isLazy Returns the lazy mode.
query Get the SQL query
setFields Set field definitions
setFilePath Set the file path
setGeometryField Set the name of the geometry field
setGeometrySrid Set the SRID of the geometry
setGeometryWkbType Set the type of the geometry
setLazy Sets the lazy mode.
setQuery Set the SQL query
setUid Set the name of the field with unique identifiers
sourceLayers Get access to the source layers
toString Convert into a QString that can be read by the virtual layer provider
toUrl Convert the definition into a QUrl
uid Get the name of the field with unique identifiers

Signals

Attributes

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.)

encoding(self) → str

Optional encoding for the provider

isReferenced(self) → bool

Is it a live layer or not ?

name(self) → str

Name of the layer

provider(self) → str

Provider key

reference(self) → str

The reference (id) of the live layer

source(self) → str

The source url used by the provider to build the layer

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

fields(self) → QgsFields

Get field definitions

filePath(self) → str

Get the file path. May be empty

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

geometryField(self) → str

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

geometrySrid(self) → int

Get the SRID of the geometry

geometryWkbType(self) → QgsWkbTypes.Type

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

hasDefinedGeometry(self) → bool

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

hasReferencedLayers(self) → bool

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

hasSourceLayer(self, name: str) → bool

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

isLazy(self) → bool

Returns the lazy mode.

Returns:True if the loading is delayed, false otherwise.

New in version 3.2.

See also

setLazy()

query(self) → str

Get the SQL query

setFields(self, fields: QgsFields)

Set field definitions

setFilePath(self, filePath: str)

Set the file path

setGeometryField(self, geometryField: str)

Set the name of the geometry field

setGeometrySrid(self, srid: int)

Set the SRID of the geometry

setGeometryWkbType(self, t: QgsWkbTypes.Type)

Set the type of the geometry

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 – True to delay the loading, false otherwise

New in version 3.2.

See also

isLazy()

setQuery(self, query: str)

Set the SQL query

setUid(self, uid: str)

Set the name of the field with unique identifiers

sourceLayers(self) → object

Get access to the source layers

toString(self) → str

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

toUrl(self) → QUrl

Convert the definition into a QUrl

uid(self) → str

Get the name of the field with unique identifiers