:mod:`Data_Mapping` --- Python Data Mappings
How Python types map to server types
Note
By default, the :py:class:`aerospike.Client` maps the supported types :py:class:`int`, :py:class:`bool`, :py:class:`str`, :py:class:`float`, :py:class:`bytearray`, :py:class:`list`, :py:class:`dict` to matching aerospike server types (int, string, double, blob, list, map). When an unsupported type is encountered, the module uses cPickle to serialize and deserialize the data, storing it into a blob of type 'Python' (AS_BYTES_PYTHON).
The functions :func:`~aerospike.set_serializer` and :func:`~aerospike.set_deserializer` allow for user-defined functions to handle serialization, instead. The user provided function will be run instead of cPickle. The serialized data is stored as type (AS_BYTES_BLOB). This type allows the storage of binary data readable by Aerospike Clients in other languages. The serialization config param of :func:`aerospike.client` registers an instance-level pair of functions that handle serialization.
Unless a user specified serializer has been provided, all other types will be stored as Python specific bytes. Python specific bytes may not be readable by Aerospike Clients for other languages.
Warning
Aerospike is introducing a new boolean data type in server version 5.6. In order to support cross client compatibility and rolling upgrades, Python client version 6.x comes with a new client config, send_bool_as. Send_bool_as configures how the client writes Python booleans and allows for opting into using the new boolean type. It is important to consider how other clients connected to the Aerospike database write booleans in order to maintain cross client compatibility. If a client reads and writes booleans as integers then the Python client should too, if they work with the same data. Send_bool_as can be set so the client writes Python booleans as AS_BYTES_PYTHON, integer, or the new server boolean type. All versions before 6.x wrote Python booleans as AS_BYTES_PYTHON.
The following table shows which Python types map directly to Aerospike server types.
Note
:class:`aerospike.KeyOrderedDict` is a special case. Like dict, KeyOrderedDict maps to the aerospike map data type. However, the map will be sorted in key order before being sent to the server, see :ref:`aerospike_map_order`.
| Python Type | Server type |
|---|---|
| int | integer |
| bool | depends on send_bool_as |
| str | string |
| unicode | string |
| float | double |
| dict | map |
| aerospike.KeyOrderedDict | key ordered map |
| list | list |
| bytearray | blob |
| aerospike.GeoJSON | GeoJSON |
It is possible to nest these datatypes. For example a list may contain a dictionary, or a dictionary may contain a list as a value.
Note
Unless a user specified serializer has been provided, all other types will be stored as Python specific bytes. Python specific bytes may not be readable by Aerospike Clients for other languages.