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authorDamian Dimmich <damian@tauri-tec.com>2014-06-24 11:23:21 +0400
committerDamian Dimmich <damian@tauri-tec.com>2014-06-24 11:23:21 +0400
commit01cc8fbacce8f571a47a3617b913e579bd666f97 (patch)
tree25428147b849bc3498be322619d819687ee813e6 /lib/sqlalchemy/dialects/postgresql/json.py
parentf10eb28d90cbf73f4757897f52bf26722f98372e (diff)
downloadsqlalchemy-01cc8fbacce8f571a47a3617b913e579bd666f97.tar.gz
initial support for JSONB - this only allows you to define the JSONB
datatype - this does not add any of the additional support for querying/indexing yet.
Diffstat (limited to 'lib/sqlalchemy/dialects/postgresql/json.py')
-rw-r--r--lib/sqlalchemy/dialects/postgresql/json.py113
1 files changed, 112 insertions, 1 deletions
diff --git a/lib/sqlalchemy/dialects/postgresql/json.py b/lib/sqlalchemy/dialects/postgresql/json.py
index 2e29185e8..37196dfb1 100644
--- a/lib/sqlalchemy/dialects/postgresql/json.py
+++ b/lib/sqlalchemy/dialects/postgresql/json.py
@@ -14,7 +14,7 @@ from ... import sql
from ...sql import elements
from ... import util
-__all__ = ('JSON', 'JSONElement')
+__all__ = ('JSON', 'JSONElement', 'JSONB')
class JSONElement(elements.BinaryExpression):
@@ -197,3 +197,114 @@ class JSON(sqltypes.TypeEngine):
ischema_names['json'] = JSON
+
+
+
+class JSONB(sqltypes.TypeEngine):
+ """Represent the Postgresql JSONB type.
+
+ The :class:`.JSONB` type stores arbitrary JSONB format data, e.g.::
+
+ data_table = Table('data_table', metadata,
+ Column('id', Integer, primary_key=True),
+ Column('data', JSONB)
+ )
+
+ with engine.connect() as conn:
+ conn.execute(
+ data_table.insert(),
+ data = {"key1": "value1", "key2": "value2"}
+ )
+
+ :class:`.JSONB` provides several operations:
+
+ * Index operations::
+
+ data_table.c.data['some key']
+
+ * Index operations returning text (required for text comparison)::
+
+ data_table.c.data['some key'].astext == 'some value'
+
+ * Index operations with a built-in CAST call::
+
+ data_table.c.data['some key'].cast(Integer) == 5
+
+ * Path index operations::
+
+ data_table.c.data[('key_1', 'key_2', ..., 'key_n')]
+
+ * Path index operations returning text (required for text comparison)::
+
+ data_table.c.data[('key_1', 'key_2', ..., 'key_n')].astext == 'some value'
+
+ Index operations return an instance of :class:`.JSONElement`, which represents
+ an expression such as ``column -> index``. This element then defines
+ methods such as :attr:`.JSONElement.astext` and :meth:`.JSONElement.cast`
+ for setting up type behavior.
+
+ The :class:`.JSON` type, when used with the SQLAlchemy ORM, does not detect
+ in-place mutations to the structure. In order to detect these, the
+ :mod:`sqlalchemy.ext.mutable` extension must be used. This extension will
+ allow "in-place" changes to the datastructure to produce events which
+ will be detected by the unit of work. See the example at :class:`.HSTORE`
+ for a simple example involving a dictionary.
+
+ Custom serializers and deserializers are specified at the dialect level,
+ that is using :func:`.create_engine`. The reason for this is that when
+ using psycopg2, the DBAPI only allows serializers at the per-cursor
+ or per-connection level. E.g.::
+
+ engine = create_engine("postgresql://scott:tiger@localhost/test",
+ json_serializer=my_serialize_fn,
+ json_deserializer=my_deserialize_fn
+ )
+
+ When using the psycopg2 dialect, the json_deserializer is registered
+ against the database using ``psycopg2.extras.register_default_json``.
+
+ .. versionadded:: 0.9.7
+
+ """
+
+ __visit_name__ = 'JSONB'
+
+ class comparator_factory(sqltypes.Concatenable.Comparator):
+ """Define comparison operations for :class:`.JSON`."""
+
+ def __getitem__(self, other):
+ """Get the value at a given key."""
+
+ return JSONElement(self.expr, other)
+
+ def _adapt_expression(self, op, other_comparator):
+ if isinstance(op, custom_op):
+ if op.opstring == '->':
+ return op, sqltypes.Text
+ return sqltypes.Concatenable.Comparator.\
+ _adapt_expression(self, op, other_comparator)
+
+ def bind_processor(self, dialect):
+ json_serializer = dialect._json_serializer or json.dumps
+ if util.py2k:
+ encoding = dialect.encoding
+ def process(value):
+ return json_serializer(value).encode(encoding)
+ else:
+ def process(value):
+ return json_serializer(value)
+ return process
+
+ def result_processor(self, dialect, coltype):
+ json_deserializer = dialect._json_deserializer or json.loads
+ if util.py2k:
+ encoding = dialect.encoding
+ def process(value):
+ return json_deserializer(value.decode(encoding))
+ else:
+ def process(value):
+ return json_deserializer(value)
+ return process
+
+
+ischema_names['jsonb'] = JSONB \ No newline at end of file