83 lines
2.8 KiB
Markdown
83 lines
2.8 KiB
Markdown
cqlengine
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===============
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cqlengine is a Cassandra CQL 3 Object Mapper for Python
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**Users of versions < 0.16, the default keyspace 'cqlengine' has been removed. Please read this before upgrading:** [Breaking Changes](https://cqlengine.readthedocs.org/en/latest/topics/models.html#keyspace-change)
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[Documentation](https://cqlengine.readthedocs.org/en/latest/)
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[Report a Bug](https://github.com/bdeggleston/cqlengine/issues)
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[Users Mailing List](https://groups.google.com/forum/?fromgroups#!forum/cqlengine-users)
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## Installation
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```
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pip install cqlengine
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```
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## Getting Started
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```python
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#first, define a model
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import uuid
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from cqlengine import columns
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from cqlengine.models import Model
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class ExampleModel(Model):
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read_repair_chance = 0.05 # optional - defaults to 0.1
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example_id = columns.UUID(primary_key=True, default=uuid.uuid4)
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example_type = columns.Integer(index=True)
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created_at = columns.DateTime()
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description = columns.Text(required=False)
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#next, setup the connection to your cassandra server(s)...
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>>> from cqlengine import connection
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>>> connection.setup(['127.0.0.1'])
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# or if you're still on cassandra 1.2
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>>> connection.setup(['127.0.0.1'], protocol_version=1)
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#...and create your CQL table
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>>> from cqlengine.management import sync_table
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>>> sync_table(ExampleModel)
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#now we can create some rows:
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>>> em1 = ExampleModel.create(example_type=0, description="example1", created_at=datetime.now())
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>>> em2 = ExampleModel.create(example_type=0, description="example2", created_at=datetime.now())
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>>> em3 = ExampleModel.create(example_type=0, description="example3", created_at=datetime.now())
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>>> em4 = ExampleModel.create(example_type=0, description="example4", created_at=datetime.now())
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>>> em5 = ExampleModel.create(example_type=1, description="example5", created_at=datetime.now())
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>>> em6 = ExampleModel.create(example_type=1, description="example6", created_at=datetime.now())
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>>> em7 = ExampleModel.create(example_type=1, description="example7", created_at=datetime.now())
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>>> em8 = ExampleModel.create(example_type=1, description="example8", created_at=datetime.now())
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#and now we can run some queries against our table
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>>> ExampleModel.objects.count()
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8
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>>> q = ExampleModel.objects(example_type=1)
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>>> q.count()
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4
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>>> for instance in q:
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>>> print instance.description
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example5
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example6
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example7
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example8
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#here we are applying additional filtering to an existing query
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#query objects are immutable, so calling filter returns a new
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#query object
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>>> q2 = q.filter(example_id=em5.example_id)
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>>> q2.count()
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1
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>>> for instance in q2:
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>>> print instance.description
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example5
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```
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## Contributing
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If you'd like to contribute to cqlengine, please read the [contributor guidelines](https://github.com/bdeggleston/cqlengine/blob/master/CONTRIBUTING.md)
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