Class: QgsAuxiliaryStorage¶
-
class
qgis.core.
QgsAuxiliaryStorage
(project: QgsProject, copy: bool = True)¶ Bases:
sip.wrapper
Constructor.
The project filename is used to build a database path at the same location, but with a different extension. Then, it’s the same logic as described for :py:class:`QgsAuxiliaryStorage`(const QString &, bool copy).
- Parameters
project – The project for which the auxiliary storage has to be used
copy – Parameter indicating if a copy of the database has to be used
QgsAuxiliaryStorage(filename: str = ‘’, copy: bool = True) Constructor.
If a valid database path is given in parameter and copy mode is deactivated, then every changes is directly committed on the original database. But if the copy mode is activated, then changes are committed on a copy of the database (a temporary file) and a save action is therefore necessary to keep modifications in the original file.
If an empty string for the database path is given in parameter, then a database is created in a temporary file whatever the copy mode.
If the database path given in parameter is not empty but does not exist, then a database is created at this location when copy mode is deactivated. When copy mode is activated, a temporary database is used instead and a save action will be necessary to create the database at the original location given in parameter.
- Parameters
filename – The path of the database
copy – Parameter indicating if a copy of the database has to be used
QgsAuxiliaryStorage(QgsAuxiliaryStorage)
Class providing some utility methods to manage auxiliary storage.
New in version 3.0: Enums
Methods
Creates an auxiliary layer for a vector layer.
Returns the path of the current database used.
Removes a table from the auxiliary storage.
Duplicates a table and its content.
Returns the underlying error string describing potential errors happening in saveAs().
Returns true if the auxiliary database yet exists for a project, false otherwise.
Returns the extension used for auxiliary databases.
Returns the target filename of the database.
Returns the status of the auxiliary storage currently defined.
Saves the current database.
Saves the current database to a new path.
Signals
Attributes
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createAuxiliaryLayer
(self, field: QgsField, layer: QgsVectorLayer) → QgsAuxiliaryLayer¶ Creates an auxiliary layer for a vector layer. A new table is created if necessary. The primary key to use to construct the auxiliary layer is given in parameter.
- Parameters
field – The primary key to join
layer – The vector layer for which the auxiliary layer has to be created
- Returns
A new auxiliary layer or a None if an error happened.
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currentFileName
(self) → str¶ Returns the path of the current database used. It may be different from the target filename if the auxiliary storage is opened in copy mode.
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deleteTable
(uri: QgsDataSourceUri) → bool¶ Removes a table from the auxiliary storage.
- Parameters
uri – The uri of the table to remove
- Returns
true if the table is well deleted, false otherwise
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duplicateTable
(uri: QgsDataSourceUri, newTable: str) → bool¶ Duplicates a table and its content.
- Parameters
uri – The uri of the table to duplicate
newTable – The name of the new table
- Returns
true if the table is well duplicated, false otherwise
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errorString
(self) → str¶ Returns the underlying error string describing potential errors happening in saveAs(). Empty by default.
New in version 3.4.
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exists
(project: QgsProject) → bool¶ Returns true if the auxiliary database yet exists for a project, false otherwise.
- Parameters
project – The project for which the database is checked
New in version 3.2.
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extension
() → str¶ Returns the extension used for auxiliary databases.
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fileName
(self) → str¶ Returns the target filename of the database.
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isValid
(self) → bool¶ Returns the status of the auxiliary storage currently defined.
- Returns
true if the auxiliary storage is valid, false otherwise
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save
(self) → bool¶ Saves the current database.
- Returns
true if everything is saved, false otherwise
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saveAs
(self, filename: str) → bool¶ Saves the current database to a new path.
- Returns
true if everything is saved, false otherwise
saveAs(self, project: QgsProject) -> bool Saves the current database to a new path for a specific project. Actually, the current filename of the project is used to deduce the path of the database to save.
- Returns
true if everything is saved, false otherwise