QEP 332: Port SQL Query History to Browser

QEP-332-sql-query-history.md

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+# QGIS Enhancement: Port SQL Query History to Browser
+
+**Date** 2025-02-27
+
+**Author** Nyall Dawson (@nyalldawson)
+
+**Contact** [email protected]
+
+**Version** QGIS 3.44-3.46
+
+# Summary
+
+As part of the long-term strategic plan to move the DB Manager plugin functionality into
+the QGIS browser panel, this proposal covers porting the "history" component of the DB
+Manager SQL dialog to the main QGIS browser.
+
+The screenshot below shows the current DB Manager history panel:
+
+![db_manager_version.png](images/qep332/db_manager_version.png)
+
+_**This is the last feature available in DB Manager's SQL window which is not yet available
+via the QGIS Browser panel.**_
+
+## Proposed Solution
+
+The existing "Execute SQL" dialog (``QgsQueryResultWidget``) will be modified to add support
+for query history. The current state of this dialog is shown below:
+
+![execute_sql.png](images/qep332/execute_sql.png)
+
+Specifically, a new toggleable action will be added to the toolbar in this dialog which will
+open a new query history panel. The dialog will be reworked to use a ``QgsPanelWidgetStack``
+as the base widget, allowing the new query history panel to be opened inline as a stacked
+``QgsPanelWidget``. (This avoids the need to open a new dialog to show the history, or
+try to squash the widget into the already full ``QgsQueryResultWidget`` layout.)
+
+Instead of the rudimentary table used in the DB Manager history panel, the existing ``QgsHistoryWidget``
+widget will be reused for the query history. This widget is the same class as is used
+by the Processing history dialog, and shows historic commands grouped nicely in chronological
+groups. The widget supports full text search through previous logged queries, and also includes
+the details of the associated connection, row count and execution time. See screenshot below.
+
+For more details on the ``QgsHistoryWidget``, see https://github.com/qgis/QGIS-Enhancement-Proposals/issues/130.
+
+![history_widget.png](images/qep332/history_widget.png)
+
+(It's worth noting that a history provider for database queries has been in place since
+April 2023 (see https://github.com/qgis/QGIS/pull/52867), so existing QGIS user profiles
+have already an extensive log of query history which is not exposed ANYWHERE in the
+GUI yet!)
+
+Double-clicking any of the entries in the history will insert that query into the current
+SQL query and immediately dismiss the history panel.
+
+### Application Integration
+
+The query history will also be exposed as a top-level action in QGIS, just like the
+Processing history dialog is. An action will be added to the ``Database`` menu
+for ``Query History...``, which will open the query history as a standalone window.
+
+Double clicking-on any of the entries in the list will open an "Execute SQL" window
+for the same connection as the original query was executed on, pre-populated with that
+query.
+
+### Provider Compatibility
+
+The history panel will be accessible wherever ``QgsQueryResultWidget`` is used, which includes:
+
+- The browser "Execute SQL" action
+- The layer context menu "Execute SQL" action
+- SQL view layer context menu "Update SQL" action
+
+Accordingly, it will be compatible with all providers which support the Execute SQL action,
+which are all existing vector database providers (Postgres, SQL Server, Oracle, HANA, GeoPackage,
+Spatialite, ESRI File GeoDatabase...)
+
+### Compatibility with DB Manager
+
+The new query history will **not** be compatible with the DB Manager history. Entries from
+the DB Manager history will not appear in the log, and queries executed through the browser
+will not appear in the DB Manager history. 
+
+## Deliverables
+
+- Query history added to the browser SQL execution windows
+- Query history available through the main window ``Database`` menu
+
+### Affected Files
+
+- QgsQueryResultWidget
+- QgsHistoryWidget