Subtransactions can be started explicitly using the
<command>SAVEPOINT</command> command, but can also be started in
other ways, such as PL/pgSQL's <command>EXCEPTION</command> clause.
- PL/Python and PL/TCL also support explicit subtransactions.
+ PL/Python and PL/Tcl also support explicit subtransactions.
Subtransactions can also be started from other subtransactions.
The top-level transaction and its child subtransactions form a
hierarchy or tree, which is why we refer to the main transaction as