Class: 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`	Gets field definitions
`filePath`	Gets the file path.
`geometryField`	Gets the name of the geometry field.
`geometrySrid`	Gets the SRID of the geometry
`geometryWkbType`	Gets the type of the geometry `QgsWkbTypes`.NoGeometry to hide any geometry `QgsWkbTypes`.Unknown for unknown types
`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`	Gets the SQL query
`setFields`	Sets field definitions
`setFilePath`	Sets the file path
`setGeometryField`	Sets the name of the geometry field
`setGeometrySrid`	Sets the SRID of the geometry
`setGeometryWkbType`	Sets the type of the geometry
`setLazy`	Sets the lazy mode.
`setQuery`	Sets the SQL query
`setSubsetString`	Sets the subsetString
`setUid`	Sets the name of the field with unique identifiers
`sourceLayers`	Gets access to the source layers
`subsetString`	Returns the subset string.
`toString`	Convert into a QString that can be read by the virtual layer provider
`toUrl`	Convert the definition into a QUrl
`uid`	Gets the name of the field with unique identifiers

Static Methods

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.

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

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.)

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

Parameters:

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

addSource(self, name: str | None, source: str | None, provider: str | None, encoding: str | None = '')[source]

Add a layer with a source, a provider and an encoding

Parameters:

name (Optional[str])
source (Optional[str])
provider (Optional[str])
encoding (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.