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.

List of all members, including inherited members

Classes

SourceLayer

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

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`	Converts the definition into a string 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

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

__init__(name: str | None, ref: str | None)

Constructor variant to build a live layer reference

Parameters:

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

__init__(name: str | None, source: str | None, provider: str | None, encoding: str | None)

Constructor variant to build a layer with a provider and a source

Parameters:

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

__init__(a0: QgsVirtualLayerDefinition.SourceLayer)

Parameters:: 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.