The SQLAlchemy :class:`_engine.Engine` object refers to a connection pool of existing
database connections. So when this object is replicated to a child process,
the goal is to ensure that no database connections are carried over. There
-are three general approaches to this:
+are four general approaches to this:
1. Disable pooling using :class:`.NullPool`. This is the most simplistic,
one shot system that prevents the :class:`_engine.Engine` from using any connection
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A pool implementation can be used directly without an engine. This could be used
-in applications that just whish to use the pool behavior without all other
+in applications that just wish to use the pool behavior without all other
SQLAlchemy features.
In the example below the default pool for the ``MySQLdb`` dialect is obtained using
:func:`_sa.create_pool_from_url`::