- Licence:
MIT
Schemas define the structure of the fields of your table. The schema handles fields validations, and ensure index unicity. There are 5 main concepts around the schemas:
Indexes
An index defines which key (or set of keys) should be unique within your table. The schema will perform checks on those indexes whenever a row is being created or updated.
Some examples:
- If you have a user table, and need usernames and emails to be unique, you will have then 2 indexes.
- If you have a session token table with a user id and a token number, you can have one index composed of two keys: user id (hash) and token number (range)
Validators
Validators are health checks on the provided data. For example: if you have a
field age, the field is most likely going to have a defined range (minimum
and maximum). If a value provided is not valid, the field validator throws an
exception, caught by the schema, and returned as part of the response (so if
more than one field is invalid, the user can be informed.)
Extensions
Extensions are only available for fetch and fetch_one method. They are
populating more fields on the returned object.
For instance: if you have a user table, and a profile table, you probably want
the user to be able to get the profile as part of the same response. So
profile can be an extension of user.
Generated fields
Generated fields are created after field validation. For instance: on a blog post, you want to capture the number of words, it could be a generated field. Those fields are saved into the database.
Operations
Field operations are used for two things: the first is to validate all the
possible value this operation contains (by using the field itself) and the
second is to write the correct query. For example:
fetch_one(username=Equal('michael')), will convert the
key into username__eq in dynamodb.
- Michael Ortali (@xethorn)