dynamorm 0.9.3

支持的模式验证库

• Schematics>；=2.0
• Marshmallow>；=2.0

示例

importdatetimefromdynamormimportDynaModel,GlobalIndex,ProjectAll# In this example we'll use Marshmallow, but you can also use Schematics too!# You can see that you have to import the schema library yourself, it is not abstracted at allfrommarshmallowimportfields# Our objects are defined as DynaModel classesclassBook(DynaModel):# Define our DynamoDB propertiesclassTable:name='prod-books'hash_key='isbn'read=25write=5classByAuthor(GlobalIndex):name='by-author'hash_key='author'read=25write=5projection=ProjectAll()# Define our data schema, each property here will become a property on instances of the Book classclassSchema:isbn=fields.String(validate=validate_isbn)title=fields.String()author=fields.String()publisher=fields.String()# NOTE: Marshmallow uses the `missing` keyword during deserialization, which occurs when we save# an object to Dynamo and the attr has no value, versus the `default` keyword, which is used when# we load a document from Dynamo and the value doesn't exist or is null.year=fields.Number(missing=lambda:datetime.datetime.utcnow().year)# Store new documents directly from dictionariesBook.put({"isbn":"12345678910","title":"Foo","author":"Mr. Bar","publisher":"Publishorama"})# Work with the classes as objects.  You can pass attributes from the schema to the constructorfoo=Book(isbn="12345678910",title="Foo",author="Mr. Bar",publisher="Publishorama")foo.save()# Or assign attributesfoo=Book()foo.isbn="12345678910"foo.title="Foo"foo.author="Mr. Bar"foo.publisher="Publishorama"# In all cases they go through Schema validation, calls to .put or .save can result in ValidationErrorfoo.save()# You can then fetch, query and scan your tables.# Get on the hash key, and/or range keybook=Book.get(isbn="12345678910")# Update items, with conditions# Here our condition ensures we don't have a race condition where someone else updates the title firstbook.update(title='Corrected Foo',conditions=(title=book.title,))# Query based on the keysBook.query(isbn__begins_with="12345")# Scan based on attributesBook.scan(author="Mr. Bar")Book.scan(author__ne="Mr. Bar")# Query based on indexesBook.ByAuthor.query(author="Mr. Bar")