.. tip:: There is no requirement that reflection must be used in order to
use SQLAlchemy with a pre-existing database. It is entirely typical that
the SQLAlchemy application declares all metadata explicitly in Python,
- such that its structure corresponds to that the existing database.
+ such that its structure corresponds to the existing database.
The metadata structure also need not include tables, columns, or other
constraints and constructs in the pre-existing database that are not needed
for the local application to function.