In the most general sense, the `Session` establishes all conversations with the database and represents a "holding zone" for all the mapped instances which you've loaded or created during its lifespan. It implements the [Unit of Work](http://martinfowler.com/eaaCatalog/unitOfWork.html) pattern, which means it keeps track of all changes which occur, and is capable of **flushing** those changes to the database as appropriate. Another important facet of the `Session` is that it's also maintaining **unique** copies of each instance, where "unique" means "only one object with a particular primary key" - this pattern is called the [Identity Map](http://martinfowler.com/eaaCatalog/identityMap.html).
-Beyond that, the `Session` implements an interface which let's you move objects in or out of the session in a variety of ways, it provides the entryway to a `Query` object which is used to query the database for data, and it also provides a transactional context for SQL operations which rides on top of the transactional capabilities of `Engine` and `Connection` objects.
+Beyond that, the `Session` implements an interface which lets you move objects in or out of the session in a variety of ways, it provides the entryway to a `Query` object which is used to query the database for data, and it also provides a transactional context for SQL operations which rides on top of the transactional capabilities of `Engine` and `Connection` objects.
## Getting a Session
projects / thirdparty / sqlalchemy / sqlalchemy.git / commitdiff
