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Merge remote branch 'upstream/devel' into devel
Conflicts: setup.py tests/__init__.py tests/testconfig.py
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@ -89,14 +89,33 @@ by the `psycopg2.extensions.adapt()` function.
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The `~cursor.execute()` method adapts its arguments to the
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`~psycopg2.extensions.ISQLQuote` protocol. Objects that conform to this
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protocol expose a `!getquoted()` method returning the SQL representation
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of the object as a string.
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of the object as a string (the method must return `!bytes` in Python 3).
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Optionally the conform object may expose a
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`~psycopg2.extensions.ISQLQuote.prepare()` method.
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The easiest way to adapt an object to an SQL string is to register an adapter
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function via the `~psycopg2.extensions.register_adapter()` function. The
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adapter function must take the value to be adapted as argument and return a
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conform object. A convenient object is the `~psycopg2.extensions.AsIs`
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wrapper, whose `!getquoted()` result is simply the `!str()`\ ing
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conversion of the wrapped object.
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There are two basic ways to have a Python object adapted to SQL:
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- the object itself is conform, or knows how to make itself conform. Such
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object must expose a `__conform__()` method that will be called with the
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protocol object as argument. The object can check that the protocol is
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`!ISQLQuote`, in which case it can return `!self` (if the object also
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implements `!getquoted()`) or a suitable wrapper object. This option is
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viable if you are the author of the object and if the object is specifically
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designed for the database (i.e. having Psycopg as a dependency and polluting
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its interface with the required methods doesn't bother you). For a simple
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example you can take a look to the source code for the
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`psycopg2.extras.Inet` object.
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- If implementing the `!ISQLQuote` interface directly in the object is not an
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option, you can use an adaptation function, taking the object to be adapted
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as argument and returning a conforming object. The adapter must be
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registered via the `~psycopg2.extensions.register_adapter()` function. A
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simple example wrapper is the `!psycopg2.extras.UUID_adapter` used by the
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`~psycopg2.extras.register_uuid()` function.
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A convenient object to write adapters is the `~psycopg2.extensions.AsIs`
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wrapper, whose `!getquoted()` result is simply the `!str()`\ ing conversion of
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the wrapped object.
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.. index::
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single: Example; Types adaptation
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@ -189,8 +189,9 @@ deal with Python objects adaptation:
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.. method:: getquoted()
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Subclasses or other conforming objects should return a valid SQL
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string representing the wrapped object. The `!ISQLQuote`
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implementation does nothing.
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string representing the wrapped object. In Python 3 the SQL must be
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returned in a `!bytes` object. The `!ISQLQuote` implementation does
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nothing.
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.. method:: prepare(conn)
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@ -94,6 +94,18 @@ Psycopg converts :sql:`decimal`\/\ :sql:`numeric` database types into Python `!D
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documentation. If you find `!psycopg2.extensions.DECIMAL` not avalable, use
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`!psycopg2._psycopg.DECIMAL` instead.
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Transferring binary data from PostgreSQL 9.0 doesn't work.
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PostgreSQL 9.0 uses by default `the "hex" format`__ to transfer
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:sql:`bytea` data: the format can't be parsed by the libpq 8.4 and
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earlier. Three options to solve the problem are:
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- set the bytea_output__ parameter to ``escape`` in the server;
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- use ``SET bytea_output TO escape`` in the client before reading binary
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data;
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- upgrade the libpq library on the client to at least 9.0.
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.. __: http://www.postgresql.org/docs/9.0/static/datatype-binary.html
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.. __: http://www.postgresql.org/docs/9.0/static/runtime-config-client.html#GUC-BYTEA-OUTPUT
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Best practices
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--------------
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@ -233,15 +233,37 @@ the SQL string that would be sent to the database.
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.. index::
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pair: Strings; Adaptation
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single: Unicode; Adaptation
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- String types: `!str`, `!unicode` are converted in SQL string syntax.
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`!unicode` objects (`!str` in Python 3) are encoded in the connection
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`~connection.encoding` to be sent to the backend: trying to send a character
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not supported by the encoding will result in an error. Received data can be
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converted either as `!str` or `!unicode`: see :ref:`unicode-handling` for
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received, either `!str` or `!unicode`
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.. index::
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single: Buffer; Adaptation
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single: bytea; Adaptation
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single: Binary string
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- String types: `!str`, `!unicode` are converted in SQL string
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syntax. `!buffer` is converted in PostgreSQL binary string syntax,
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suitable for :sql:`bytea` fields. When reading textual fields, either
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`!str` or `!unicode` can be received: see
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:ref:`unicode-handling`.
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- Binary types: Python types such as `!bytes`, `!bytearray`, `!buffer`,
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`!memoryview` are converted in PostgreSQL binary string syntax, suitable for
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:sql:`bytea` fields. Received data is returned as `!buffer` (in Python 2) or
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`!memoryview` (in Python 3).
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.. warning::
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PostgreSQL 9 uses by default `a new "hex" format`__ to emit :sql:`bytea`
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fields. Unfortunately this format can't be parsed by libpq versions
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before 9.0. This means that using a library client with version lesser
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than 9.0 to talk with a server 9.0 or later you may have problems
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receiving :sql:`bytea` data. To work around this problem you can set the
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`bytea_output`__ parameter to ``escape``, either in the server
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configuration or in the client session using a query such as ``SET
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bytea_output TO escape;`` before trying to receive binary data.
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.. __: http://www.postgresql.org/docs/9.0/static/datatype-binary.html
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.. __: http://www.postgresql.org/docs/9.0/static/runtime-config-client.html#GUC-BYTEA-OUTPUT
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.. index::
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single: Adaptation; Date/Time objects
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@ -338,8 +360,8 @@ defined on the database connection (the `PostgreSQL encoding`__, available in
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.. __: http://www.postgresql.org/docs/9.0/static/multibyte.html
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.. __: http://docs.python.org/library/codecs.html#standard-encodings
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When reading data from the database, the strings returned are usually 8 bit
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`!str` objects encoded in the database client encoding::
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When reading data from the database, in Python 2 the strings returned are
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usually 8 bit `!str` objects encoded in the database client encoding::
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>>> print conn.encoding
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UTF8
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@ -356,9 +378,10 @@ When reading data from the database, the strings returned are usually 8 bit
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>>> print type(x), repr(x)
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<type 'str'> '\xe0\xe8\xec\xf2\xf9\xa4'
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In order to obtain `!unicode` objects instead, it is possible to
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register a typecaster so that PostgreSQL textual types are automatically
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*decoded* using the current client encoding::
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In Python 3 instead the strings are automatically *decoded* in the connection
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`~connection.encoding`, as the `!str` object can represent Unicode characters.
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In Python 2 you must register a :ref:`typecaster
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<type-casting-from-sql-to-python>` in order to receive `!unicode` objects::
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>>> psycopg2.extensions.register_type(psycopg2.extensions.UNICODE, cur)
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@ -375,9 +398,9 @@ the connection or globally: see the function
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.. note::
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If you want to receive uniformly all your database input in Unicode, you
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can register the related typecasters globally as soon as Psycopg is
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imported::
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In Python 2, if you want to receive uniformly all your database input in
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Unicode, you can register the related typecasters globally as soon as
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Psycopg is imported::
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import psycopg2
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import psycopg2.extensions
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@ -835,14 +835,22 @@ class CompositeCaster(object):
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# Store the transaction status of the connection to revert it after use
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conn_status = conn.status
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# Use the correct schema
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if '.' in name:
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schema, tname = name.split('.', 1)
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else:
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tname = name
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schema = 'public'
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# get the type oid and attributes
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curs.execute("""\
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SELECT t.oid, attname, atttypid
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FROM pg_type t
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JOIN pg_namespace ns ON typnamespace = ns.oid
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JOIN pg_attribute a ON attrelid = typrelid
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WHERE typname = %s and nspname = 'public';
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""", (name, ))
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WHERE typname = %s and nspname = %s
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ORDER BY attnum;
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""", (tname, schema))
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recs = curs.fetchall()
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type_oid = recs[0][0]
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type_attrs = [ (r[1], r[2]) for r in recs ]
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return CompositeCaster(name, type_oid, type_attrs)
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return CompositeCaster(tname, type_oid, type_attrs)
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def register_composite(name, conn_or_curs, globally=False):
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"""Register a typecaster to convert a composite type into a tuple.
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@ -525,6 +525,24 @@ class AdaptTypeTestCase(unittest.TestCase):
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conn1.close()
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conn2.close()
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@skip_if_no_composite
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def test_composite_namespace(self):
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curs = self.conn.cursor()
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curs.execute("""
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select nspname from pg_namespace
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where nspname = 'typens';
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""")
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if not curs.fetchone():
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curs.execute("create schema typens;")
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self.conn.commit()
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self._create_type("typens.typens_ii",
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[("a", "integer"), ("b", "integer")])
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t = psycopg2.extras.register_composite(
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"typens.typens_ii", self.conn)
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curs.execute("select (4,8)::typens.typens_ii")
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self.assertEqual(curs.fetchone()[0], (4,8))
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def _create_type(self, name, fields):
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curs = self.conn.cursor()
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try:
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curs.execute("create type %s as (%s);" % (name,
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", ".join(["%s %s" % p for p in fields])))
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if '.' in name:
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schema, name = name.split('.')
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else:
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schema = 'public'
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curs.execute("""\
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SELECT t.oid
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FROM pg_type t JOIN pg_namespace ns ON typnamespace = ns.oid
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WHERE typname = %s and nspname = 'public';
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""", (name,))
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WHERE typname = %s and nspname = %s;
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""", (name, schema))
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oid = curs.fetchone()[0]
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self.conn.commit()
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return oid
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