bpo-46402: Promote SQLite URI tricks in sqlite3 docs (GH-30660)

Provide some examples of URI parameters in sqlite connect().

Co-authored-by: Ned Batchelder <[email protected]>

Author: Erlend Egeberg Aasland

Doc/library/sqlite3.rst

@@ -273,14 +273,28 @@ Module functions and constants
    for the connection, you can set the *cached_statements* parameter. The currently
    implemented default is to cache 128 statements.
 
-   If *uri* is true, *database* is interpreted as a URI. This allows you
-   to specify options. For example, to open a database in read-only mode
-   you can use::
-
-       db = sqlite3.connect('file:path/to/database?mode=ro', uri=True)
-
-   More information about this feature, including a list of recognized options, can
-   be found in the `SQLite URI documentation <https://www.sqlite.org/uri.html>`_.
+   If *uri* is :const:`True`, *database* is interpreted as a
+   :abbr:`URI (Uniform Resource Identifier)` with a file path and an optional
+   query string.  The scheme part *must* be ``"file:"``.  The path can be a
+   relative or absolute file path.  The query string allows us to pass
+   parameters to SQLite. Some useful URI tricks include::
+
+       # Open a database in read-only mode.
+       con = sqlite3.connect("file:template.db?mode=ro", uri=True)
+
+       # Don't implicitly create a new database file if it does not already exist.
+       # Will raise sqlite3.OperationalError if unable to open a database file.
+       con = sqlite3.connect("file:nosuchdb.db?mode=rw", uri=True)
+
+       # Create a shared named in-memory database.
+       con1 = sqlite3.connect("file:mem1?mode=memory&cache=shared", uri=True)
+       con2 = sqlite3.connect("file:mem1?mode=memory&cache=shared", uri=True)
+       con1.executescript("create table t(t); insert into t values(28);")
+       rows = con2.execute("select * from t").fetchall()
+
+   More information about this feature, including a list of recognized
+   parameters, can be found in the
+   `SQLite URI documentation <https://www.sqlite.org/uri.html>`_.
 
    .. audit-event:: sqlite3.connect database sqlite3.connect
    .. audit-event:: sqlite3.connect/handle connection_handle sqlite3.connect