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SickRage/lib/sqlalchemy/dialects/postgresql/base.py
echel0n ddea462f0b More fixes for SQLAlchemy
2014-05-04 21:05:43 -07:00

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# postgresql/base.py
# Copyright (C) 2005-2014 the SQLAlchemy authors and contributors <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""
.. dialect:: postgresql
:name: PostgreSQL
Sequences/SERIAL
----------------
PostgreSQL supports sequences, and SQLAlchemy uses these as the default means
of creating new primary key values for integer-based primary key columns. When
creating tables, SQLAlchemy will issue the ``SERIAL`` datatype for
integer-based primary key columns, which generates a sequence and server side
default corresponding to the column.
To specify a specific named sequence to be used for primary key generation,
use the :func:`~sqlalchemy.schema.Sequence` construct::
Table('sometable', metadata,
Column('id', Integer, Sequence('some_id_seq'), primary_key=True)
)
When SQLAlchemy issues a single INSERT statement, to fulfill the contract of
having the "last insert identifier" available, a RETURNING clause is added to
the INSERT statement which specifies the primary key columns should be
returned after the statement completes. The RETURNING functionality only takes
place if Postgresql 8.2 or later is in use. As a fallback approach, the
sequence, whether specified explicitly or implicitly via ``SERIAL``, is
executed independently beforehand, the returned value to be used in the
subsequent insert. Note that when an
:func:`~sqlalchemy.sql.expression.insert()` construct is executed using
"executemany" semantics, the "last inserted identifier" functionality does not
apply; no RETURNING clause is emitted nor is the sequence pre-executed in this
case.
To force the usage of RETURNING by default off, specify the flag
``implicit_returning=False`` to :func:`.create_engine`.
.. _postgresql_isolation_level:
Transaction Isolation Level
---------------------------
All Postgresql dialects support setting of transaction isolation level
both via a dialect-specific parameter ``isolation_level``
accepted by :func:`.create_engine`,
as well as the ``isolation_level`` argument as passed to :meth:`.Connection.execution_options`.
When using a non-psycopg2 dialect, this feature works by issuing the
command ``SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL
<level>`` for each new connection.
To set isolation level using :func:`.create_engine`::
engine = create_engine(
"postgresql+pg8000://scott:tiger@localhost/test",
isolation_level="READ UNCOMMITTED"
)
To set using per-connection execution options::
connection = engine.connect()
connection = connection.execution_options(isolation_level="READ COMMITTED")
Valid values for ``isolation_level`` include:
* ``READ COMMITTED``
* ``READ UNCOMMITTED``
* ``REPEATABLE READ``
* ``SERIALIZABLE``
The :mod:`~sqlalchemy.dialects.postgresql.psycopg2` dialect also offers the special level ``AUTOCOMMIT``. See
:ref:`psycopg2_isolation_level` for details.
.. _postgresql_schema_reflection:
Remote-Schema Table Introspection and Postgresql search_path
------------------------------------------------------------
The Postgresql dialect can reflect tables from any schema. The
:paramref:`.Table.schema` argument, or alternatively the
:paramref:`.MetaData.reflect.schema` argument determines which schema will
be searched for the table or tables. The reflected :class:`.Table` objects
will in all cases retain this ``.schema`` attribute as was specified. However,
with regards to tables which these :class:`.Table` objects refer to via
foreign key constraint, a decision must be made as to how the ``.schema``
is represented in those remote tables, in the case where that remote
schema name is also a member of the current
`Postgresql search path <http://www.postgresql.org/docs/9.0/static/ddl-schemas.html#DDL-SCHEMAS-PATH>`_.
By default, the Postgresql dialect mimics the behavior encouraged by
Postgresql's own ``pg_get_constraintdef()`` builtin procedure. This function
returns a sample definition for a particular foreign key constraint,
omitting the referenced schema name from that definition when the name is
also in the Postgresql schema search path. The interaction below
illustrates this behavior::
test=> CREATE TABLE test_schema.referred(id INTEGER PRIMARY KEY);
CREATE TABLE
test=> CREATE TABLE referring(
test(> id INTEGER PRIMARY KEY,
test(> referred_id INTEGER REFERENCES test_schema.referred(id));
CREATE TABLE
test=> SET search_path TO public, test_schema;
test=> SELECT pg_catalog.pg_get_constraintdef(r.oid, true) FROM
test-> pg_catalog.pg_class c JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
test-> JOIN pg_catalog.pg_constraint r ON c.oid = r.conrelid
test-> WHERE c.relname='referring' AND r.contype = 'f'
test-> ;
pg_get_constraintdef
---------------------------------------------------
FOREIGN KEY (referred_id) REFERENCES referred(id)
(1 row)
Above, we created a table ``referred`` as a member of the remote schema ``test_schema``, however
when we added ``test_schema`` to the PG ``search_path`` and then asked ``pg_get_constraintdef()``
for the ``FOREIGN KEY`` syntax, ``test_schema`` was not included in the
output of the function.
On the other hand, if we set the search path back to the typical default
of ``public``::
test=> SET search_path TO public;
SET
The same query against ``pg_get_constraintdef()`` now returns the fully
schema-qualified name for us::
test=> SELECT pg_catalog.pg_get_constraintdef(r.oid, true) FROM
test-> pg_catalog.pg_class c JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
test-> JOIN pg_catalog.pg_constraint r ON c.oid = r.conrelid
test-> WHERE c.relname='referring' AND r.contype = 'f';
pg_get_constraintdef
---------------------------------------------------------------
FOREIGN KEY (referred_id) REFERENCES test_schema.referred(id)
(1 row)
SQLAlchemy will by default use the return value of ``pg_get_constraintdef()``
in order to determine the remote schema name. That is, if our ``search_path``
were set to include ``test_schema``, and we invoked a table
reflection process as follows::
>>> from sqlalchemy import Table, MetaData, create_engine
>>> engine = create_engine("postgresql://scott:tiger@localhost/test")
>>> with engine.connect() as conn:
... conn.execute("SET search_path TO test_schema, public")
... meta = MetaData()
... referring = Table('referring', meta, autoload=True, autoload_with=conn)
...
<sqlalchemy.engine.result.ResultProxy object at 0x101612ed0>
The above process would deliver to the :attr:`.MetaData.tables` collection
``referred`` table named **without** the schema::
>>> meta.tables['referred'].schema is None
True
To alter the behavior of reflection such that the referred schema is maintained
regardless of the ``search_path`` setting, use the ``postgresql_ignore_search_path``
option, which can be specified as a dialect-specific argument to both
:class:`.Table` as well as :meth:`.MetaData.reflect`::
>>> with engine.connect() as conn:
... conn.execute("SET search_path TO test_schema, public")
... meta = MetaData()
... referring = Table('referring', meta, autoload=True, autoload_with=conn,
... postgresql_ignore_search_path=True)
...
<sqlalchemy.engine.result.ResultProxy object at 0x1016126d0>
We will now have ``test_schema.referred`` stored as schema-qualified::
>>> meta.tables['test_schema.referred'].schema
'test_schema'
.. sidebar:: Best Practices for Postgresql Schema reflection
The description of Postgresql schema reflection behavior is complex, and is
the product of many years of dealing with widely varied use cases and user preferences.
But in fact, there's no need to understand any of it if you just stick to the simplest
use pattern: leave the ``search_path`` set to its default of ``public`` only, never refer
to the name ``public`` as an explicit schema name otherwise, and
refer to all other schema names explicitly when building
up a :class:`.Table` object. The options described here are only for those users
who can't, or prefer not to, stay within these guidelines.
Note that **in all cases**, the "default" schema is always reflected as ``None``.
The "default" schema on Postgresql is that which is returned by the
Postgresql ``current_schema()`` function. On a typical Postgresql installation,
this is the name ``public``. So a table that refers to another which is
in the ``public`` (i.e. default) schema will always have the ``.schema`` attribute
set to ``None``.
.. versionadded:: 0.9.2 Added the ``postgresql_ignore_search_path``
dialect-level option accepted by :class:`.Table` and :meth:`.MetaData.reflect`.
.. seealso::
`The Schema Search Path <http://www.postgresql.org/docs/9.0/static/ddl-schemas.html#DDL-SCHEMAS-PATH>`_ - on the Postgresql website.
INSERT/UPDATE...RETURNING
-------------------------
The dialect supports PG 8.2's ``INSERT..RETURNING``, ``UPDATE..RETURNING`` and
``DELETE..RETURNING`` syntaxes. ``INSERT..RETURNING`` is used by default
for single-row INSERT statements in order to fetch newly generated
primary key identifiers. To specify an explicit ``RETURNING`` clause,
use the :meth:`._UpdateBase.returning` method on a per-statement basis::
# INSERT..RETURNING
result = table.insert().returning(table.c.col1, table.c.col2).\\
values(name='foo')
print result.fetchall()
# UPDATE..RETURNING
result = table.update().returning(table.c.col1, table.c.col2).\\
where(table.c.name=='foo').values(name='bar')
print result.fetchall()
# DELETE..RETURNING
result = table.delete().returning(table.c.col1, table.c.col2).\\
where(table.c.name=='foo')
print result.fetchall()
.. _postgresql_match:
Full Text Search
----------------
SQLAlchemy makes available the Postgresql ``@@`` operator via the
:meth:`.ColumnElement.match` method on any textual column expression.
On a Postgresql dialect, an expression like the following::
select([sometable.c.text.match("search string")])
will emit to the database::
SELECT text @@ to_tsquery('search string') FROM table
The Postgresql text search functions such as ``to_tsquery()``
and ``to_tsvector()`` are available
explicitly using the standard :attr:`.func` construct. For example::
select([
func.to_tsvector('fat cats ate rats').match('cat & rat')
])
Emits the equivalent of::
SELECT to_tsvector('fat cats ate rats') @@ to_tsquery('cat & rat')
The :class:`.postgresql.TSVECTOR` type can provide for explicit CAST::
from sqlalchemy.dialects.postgresql import TSVECTOR
from sqlalchemy import select, cast
select([cast("some text", TSVECTOR)])
produces a statement equivalent to::
SELECT CAST('some text' AS TSVECTOR) AS anon_1
FROM ONLY ...
------------------------
The dialect supports PostgreSQL's ONLY keyword for targeting only a particular
table in an inheritance hierarchy. This can be used to produce the
``SELECT ... FROM ONLY``, ``UPDATE ONLY ...``, and ``DELETE FROM ONLY ...``
syntaxes. It uses SQLAlchemy's hints mechanism::
# SELECT ... FROM ONLY ...
result = table.select().with_hint(table, 'ONLY', 'postgresql')
print result.fetchall()
# UPDATE ONLY ...
table.update(values=dict(foo='bar')).with_hint('ONLY',
dialect_name='postgresql')
# DELETE FROM ONLY ...
table.delete().with_hint('ONLY', dialect_name='postgresql')
.. _postgresql_indexes:
Postgresql-Specific Index Options
---------------------------------
Several extensions to the :class:`.Index` construct are available, specific
to the PostgreSQL dialect.
Partial Indexes
^^^^^^^^^^^^^^^^
Partial indexes add criterion to the index definition so that the index is
applied to a subset of rows. These can be specified on :class:`.Index`
using the ``postgresql_where`` keyword argument::
Index('my_index', my_table.c.id, postgresql_where=tbl.c.value > 10)
Operator Classes
^^^^^^^^^^^^^^^^^
PostgreSQL allows the specification of an *operator class* for each column of
an index (see
http://www.postgresql.org/docs/8.3/interactive/indexes-opclass.html).
The :class:`.Index` construct allows these to be specified via the
``postgresql_ops`` keyword argument::
Index('my_index', my_table.c.id, my_table.c.data,
postgresql_ops={
'data': 'text_pattern_ops',
'id': 'int4_ops'
})
.. versionadded:: 0.7.2
``postgresql_ops`` keyword argument to :class:`.Index` construct.
Note that the keys in the ``postgresql_ops`` dictionary are the "key" name of
the :class:`.Column`, i.e. the name used to access it from the ``.c``
collection of :class:`.Table`, which can be configured to be different than
the actual name of the column as expressed in the database.
Index Types
^^^^^^^^^^^^
PostgreSQL provides several index types: B-Tree, Hash, GiST, and GIN, as well
as the ability for users to create their own (see
http://www.postgresql.org/docs/8.3/static/indexes-types.html). These can be
specified on :class:`.Index` using the ``postgresql_using`` keyword argument::
Index('my_index', my_table.c.data, postgresql_using='gin')
The value passed to the keyword argument will be simply passed through to the
underlying CREATE INDEX command, so it *must* be a valid index type for your
version of PostgreSQL.
"""
from collections import defaultdict
import re
from ... import sql, schema, exc, util
from ...engine import default, reflection
from ...sql import compiler, expression, operators
from ... import types as sqltypes
try:
from uuid import UUID as _python_UUID
except ImportError:
_python_UUID = None
from sqlalchemy.types import INTEGER, BIGINT, SMALLINT, VARCHAR, \
CHAR, TEXT, FLOAT, NUMERIC, \
DATE, BOOLEAN, REAL
RESERVED_WORDS = set(
["all", "analyse", "analyze", "and", "any", "array", "as", "asc",
"asymmetric", "both", "case", "cast", "check", "collate", "column",
"constraint", "create", "current_catalog", "current_date",
"current_role", "current_time", "current_timestamp", "current_user",
"default", "deferrable", "desc", "distinct", "do", "else", "end",
"except", "false", "fetch", "for", "foreign", "from", "grant", "group",
"having", "in", "initially", "intersect", "into", "leading", "limit",
"localtime", "localtimestamp", "new", "not", "null", "of", "off", "offset",
"old", "on", "only", "or", "order", "placing", "primary", "references",
"returning", "select", "session_user", "some", "symmetric", "table",
"then", "to", "trailing", "true", "union", "unique", "user", "using",
"variadic", "when", "where", "window", "with", "authorization",
"between", "binary", "cross", "current_schema", "freeze", "full",
"ilike", "inner", "is", "isnull", "join", "left", "like", "natural",
"notnull", "outer", "over", "overlaps", "right", "similar", "verbose"
])
_DECIMAL_TYPES = (1231, 1700)
_FLOAT_TYPES = (700, 701, 1021, 1022)
_INT_TYPES = (20, 21, 23, 26, 1005, 1007, 1016)
class BYTEA(sqltypes.LargeBinary):
__visit_name__ = 'BYTEA'
class DOUBLE_PRECISION(sqltypes.Float):
__visit_name__ = 'DOUBLE_PRECISION'
class INET(sqltypes.TypeEngine):
__visit_name__ = "INET"
PGInet = INET
class CIDR(sqltypes.TypeEngine):
__visit_name__ = "CIDR"
PGCidr = CIDR
class MACADDR(sqltypes.TypeEngine):
__visit_name__ = "MACADDR"
PGMacAddr = MACADDR
class TIMESTAMP(sqltypes.TIMESTAMP):
def __init__(self, timezone=False, precision=None):
super(TIMESTAMP, self).__init__(timezone=timezone)
self.precision = precision
class TIME(sqltypes.TIME):
def __init__(self, timezone=False, precision=None):
super(TIME, self).__init__(timezone=timezone)
self.precision = precision
class INTERVAL(sqltypes.TypeEngine):
"""Postgresql INTERVAL type.
The INTERVAL type may not be supported on all DBAPIs.
It is known to work on psycopg2 and not pg8000 or zxjdbc.
"""
__visit_name__ = 'INTERVAL'
def __init__(self, precision=None):
self.precision = precision
@classmethod
def _adapt_from_generic_interval(cls, interval):
return INTERVAL(precision=interval.second_precision)
@property
def _type_affinity(self):
return sqltypes.Interval
PGInterval = INTERVAL
class BIT(sqltypes.TypeEngine):
__visit_name__ = 'BIT'
def __init__(self, length=None, varying=False):
if not varying:
# BIT without VARYING defaults to length 1
self.length = length or 1
else:
# but BIT VARYING can be unlimited-length, so no default
self.length = length
self.varying = varying
PGBit = BIT
class UUID(sqltypes.TypeEngine):
"""Postgresql UUID type.
Represents the UUID column type, interpreting
data either as natively returned by the DBAPI
or as Python uuid objects.
The UUID type may not be supported on all DBAPIs.
It is known to work on psycopg2 and not pg8000.
"""
__visit_name__ = 'UUID'
def __init__(self, as_uuid=False):
"""Construct a UUID type.
:param as_uuid=False: if True, values will be interpreted
as Python uuid objects, converting to/from string via the
DBAPI.
"""
if as_uuid and _python_UUID is None:
raise NotImplementedError(
"This version of Python does not support the native UUID type."
)
self.as_uuid = as_uuid
def bind_processor(self, dialect):
if self.as_uuid:
def process(value):
if value is not None:
value = util.text_type(value)
return value
return process
else:
return None
def result_processor(self, dialect, coltype):
if self.as_uuid:
def process(value):
if value is not None:
value = _python_UUID(value)
return value
return process
else:
return None
PGUuid = UUID
class TSVECTOR(sqltypes.TypeEngine):
"""The :class:`.postgresql.TSVECTOR` type implements the Postgresql
text search type TSVECTOR.
It can be used to do full text queries on natural language
documents.
.. versionadded:: 0.9.0
.. seealso::
:ref:`postgresql_match`
"""
__visit_name__ = 'TSVECTOR'
class _Slice(expression.ColumnElement):
__visit_name__ = 'slice'
type = sqltypes.NULLTYPE
def __init__(self, slice_, source_comparator):
self.start = source_comparator._check_literal(
source_comparator.expr,
operators.getitem, slice_.start)
self.stop = source_comparator._check_literal(
source_comparator.expr,
operators.getitem, slice_.stop)
class Any(expression.ColumnElement):
"""Represent the clause ``left operator ANY (right)``. ``right`` must be
an array expression.
.. seealso::
:class:`.postgresql.ARRAY`
:meth:`.postgresql.ARRAY.Comparator.any` - ARRAY-bound method
"""
__visit_name__ = 'any'
def __init__(self, left, right, operator=operators.eq):
self.type = sqltypes.Boolean()
self.left = expression._literal_as_binds(left)
self.right = right
self.operator = operator
class All(expression.ColumnElement):
"""Represent the clause ``left operator ALL (right)``. ``right`` must be
an array expression.
.. seealso::
:class:`.postgresql.ARRAY`
:meth:`.postgresql.ARRAY.Comparator.all` - ARRAY-bound method
"""
__visit_name__ = 'all'
def __init__(self, left, right, operator=operators.eq):
self.type = sqltypes.Boolean()
self.left = expression._literal_as_binds(left)
self.right = right
self.operator = operator
class array(expression.Tuple):
"""A Postgresql ARRAY literal.
This is used to produce ARRAY literals in SQL expressions, e.g.::
from sqlalchemy.dialects.postgresql import array
from sqlalchemy.dialects import postgresql
from sqlalchemy import select, func
stmt = select([
array([1,2]) + array([3,4,5])
])
print stmt.compile(dialect=postgresql.dialect())
Produces the SQL::
SELECT ARRAY[%(param_1)s, %(param_2)s] ||
ARRAY[%(param_3)s, %(param_4)s, %(param_5)s]) AS anon_1
An instance of :class:`.array` will always have the datatype
:class:`.ARRAY`. The "inner" type of the array is inferred from
the values present, unless the ``type_`` keyword argument is passed::
array(['foo', 'bar'], type_=CHAR)
.. versionadded:: 0.8 Added the :class:`~.postgresql.array` literal type.
See also:
:class:`.postgresql.ARRAY`
"""
__visit_name__ = 'array'
def __init__(self, clauses, **kw):
super(array, self).__init__(*clauses, **kw)
self.type = ARRAY(self.type)
def _bind_param(self, operator, obj):
return array(*[
expression.BindParameter(None, o, _compared_to_operator=operator,
_compared_to_type=self.type, unique=True)
for o in obj
])
def self_group(self, against=None):
return self
class ARRAY(sqltypes.Concatenable, sqltypes.TypeEngine):
"""Postgresql ARRAY type.
Represents values as Python lists.
An :class:`.ARRAY` type is constructed given the "type"
of element::
mytable = Table("mytable", metadata,
Column("data", ARRAY(Integer))
)
The above type represents an N-dimensional array,
meaning Postgresql will interpret values with any number
of dimensions automatically. To produce an INSERT
construct that passes in a 1-dimensional array of integers::
connection.execute(
mytable.insert(),
data=[1,2,3]
)
The :class:`.ARRAY` type can be constructed given a fixed number
of dimensions::
mytable = Table("mytable", metadata,
Column("data", ARRAY(Integer, dimensions=2))
)
This has the effect of the :class:`.ARRAY` type
specifying that number of bracketed blocks when a :class:`.Table`
is used in a CREATE TABLE statement, or when the type is used
within a :func:`.expression.cast` construct; it also causes
the bind parameter and result set processing of the type
to optimize itself to expect exactly that number of dimensions.
Note that Postgresql itself still allows N dimensions with such a type.
SQL expressions of type :class:`.ARRAY` have support for "index" and
"slice" behavior. The Python ``[]`` operator works normally here, given
integer indexes or slices. Note that Postgresql arrays default
to 1-based indexing. The operator produces binary expression
constructs which will produce the appropriate SQL, both for
SELECT statements::
select([mytable.c.data[5], mytable.c.data[2:7]])
as well as UPDATE statements when the :meth:`.Update.values` method
is used::
mytable.update().values({
mytable.c.data[5]: 7,
mytable.c.data[2:7]: [1, 2, 3]
})
:class:`.ARRAY` provides special methods for containment operations,
e.g.::
mytable.c.data.contains([1, 2])
For a full list of special methods see :class:`.ARRAY.Comparator`.
.. versionadded:: 0.8 Added support for index and slice operations
to the :class:`.ARRAY` type, including support for UPDATE
statements, and special array containment operations.
The :class:`.ARRAY` type may not be supported on all DBAPIs.
It is known to work on psycopg2 and not pg8000.
See also:
:class:`.postgresql.array` - produce a literal array value.
"""
__visit_name__ = 'ARRAY'
class Comparator(sqltypes.Concatenable.Comparator):
"""Define comparison operations for :class:`.ARRAY`."""
def __getitem__(self, index):
if isinstance(index, slice):
index = _Slice(index, self)
return_type = self.type
else:
return_type = self.type.item_type
return self._binary_operate(self.expr, operators.getitem, index,
result_type=return_type)
def any(self, other, operator=operators.eq):
"""Return ``other operator ANY (array)`` clause.
Argument places are switched, because ANY requires array
expression to be on the right hand-side.
E.g.::
from sqlalchemy.sql import operators
conn.execute(
select([table.c.data]).where(
table.c.data.any(7, operator=operators.lt)
)
)
:param other: expression to be compared
:param operator: an operator object from the
:mod:`sqlalchemy.sql.operators`
package, defaults to :func:`.operators.eq`.
.. seealso::
:class:`.postgresql.Any`
:meth:`.postgresql.ARRAY.Comparator.all`
"""
return Any(other, self.expr, operator=operator)
def all(self, other, operator=operators.eq):
"""Return ``other operator ALL (array)`` clause.
Argument places are switched, because ALL requires array
expression to be on the right hand-side.
E.g.::
from sqlalchemy.sql import operators
conn.execute(
select([table.c.data]).where(
table.c.data.all(7, operator=operators.lt)
)
)
:param other: expression to be compared
:param operator: an operator object from the
:mod:`sqlalchemy.sql.operators`
package, defaults to :func:`.operators.eq`.
.. seealso::
:class:`.postgresql.All`
:meth:`.postgresql.ARRAY.Comparator.any`
"""
return All(other, self.expr, operator=operator)
def contains(self, other, **kwargs):
"""Boolean expression. Test if elements are a superset of the
elements of the argument array expression.
"""
return self.expr.op('@>')(other)
def contained_by(self, other):
"""Boolean expression. Test if elements are a proper subset of the
elements of the argument array expression.
"""
return self.expr.op('<@')(other)
def overlap(self, other):
"""Boolean expression. Test if array has elements in common with
an argument array expression.
"""
return self.expr.op('&&')(other)
def _adapt_expression(self, op, other_comparator):
if isinstance(op, operators.custom_op):
if op.opstring in ['@>', '<@', '&&']:
return op, sqltypes.Boolean
return sqltypes.Concatenable.Comparator.\
_adapt_expression(self, op, other_comparator)
comparator_factory = Comparator
def __init__(self, item_type, as_tuple=False, dimensions=None):
"""Construct an ARRAY.
E.g.::
Column('myarray', ARRAY(Integer))
Arguments are:
:param item_type: The data type of items of this array. Note that
dimensionality is irrelevant here, so multi-dimensional arrays like
``INTEGER[][]``, are constructed as ``ARRAY(Integer)``, not as
``ARRAY(ARRAY(Integer))`` or such.
:param as_tuple=False: Specify whether return results
should be converted to tuples from lists. DBAPIs such
as psycopg2 return lists by default. When tuples are
returned, the results are hashable.
:param dimensions: if non-None, the ARRAY will assume a fixed
number of dimensions. This will cause the DDL emitted for this
ARRAY to include the exact number of bracket clauses ``[]``,
and will also optimize the performance of the type overall.
Note that PG arrays are always implicitly "non-dimensioned",
meaning they can store any number of dimensions no matter how
they were declared.
"""
if isinstance(item_type, ARRAY):
raise ValueError("Do not nest ARRAY types; ARRAY(basetype) "
"handles multi-dimensional arrays of basetype")
if isinstance(item_type, type):
item_type = item_type()
self.item_type = item_type
self.as_tuple = as_tuple
self.dimensions = dimensions
@property
def python_type(self):
return list
def compare_values(self, x, y):
return x == y
def _proc_array(self, arr, itemproc, dim, collection):
if dim is None:
arr = list(arr)
if dim == 1 or dim is None and (
# this has to be (list, tuple), or at least
# not hasattr('__iter__'), since Py3K strings
# etc. have __iter__
not arr or not isinstance(arr[0], (list, tuple))):
if itemproc:
return collection(itemproc(x) for x in arr)
else:
return collection(arr)
else:
return collection(
self._proc_array(
x, itemproc,
dim - 1 if dim is not None else None,
collection)
for x in arr
)
def bind_processor(self, dialect):
item_proc = self.item_type.\
dialect_impl(dialect).\
bind_processor(dialect)
def process(value):
if value is None:
return value
else:
return self._proc_array(
value,
item_proc,
self.dimensions,
list)
return process
def result_processor(self, dialect, coltype):
item_proc = self.item_type.\
dialect_impl(dialect).\
result_processor(dialect, coltype)
def process(value):
if value is None:
return value
else:
return self._proc_array(
value,
item_proc,
self.dimensions,
tuple if self.as_tuple else list)
return process
PGArray = ARRAY
class ENUM(sqltypes.Enum):
"""Postgresql ENUM type.
This is a subclass of :class:`.types.Enum` which includes
support for PG's ``CREATE TYPE``.
:class:`~.postgresql.ENUM` is used automatically when
using the :class:`.types.Enum` type on PG assuming
the ``native_enum`` is left as ``True``. However, the
:class:`~.postgresql.ENUM` class can also be instantiated
directly in order to access some additional Postgresql-specific
options, namely finer control over whether or not
``CREATE TYPE`` should be emitted.
Note that both :class:`.types.Enum` as well as
:class:`~.postgresql.ENUM` feature create/drop
methods; the base :class:`.types.Enum` type ultimately
delegates to the :meth:`~.postgresql.ENUM.create` and
:meth:`~.postgresql.ENUM.drop` methods present here.
"""
def __init__(self, *enums, **kw):
"""Construct an :class:`~.postgresql.ENUM`.
Arguments are the same as that of
:class:`.types.Enum`, but also including
the following parameters.
:param create_type: Defaults to True.
Indicates that ``CREATE TYPE`` should be
emitted, after optionally checking for the
presence of the type, when the parent
table is being created; and additionally
that ``DROP TYPE`` is called when the table
is dropped. When ``False``, no check
will be performed and no ``CREATE TYPE``
or ``DROP TYPE`` is emitted, unless
:meth:`~.postgresql.ENUM.create`
or :meth:`~.postgresql.ENUM.drop`
are called directly.
Setting to ``False`` is helpful
when invoking a creation scheme to a SQL file
without access to the actual database -
the :meth:`~.postgresql.ENUM.create` and
:meth:`~.postgresql.ENUM.drop` methods can
be used to emit SQL to a target bind.
.. versionadded:: 0.7.4
"""
self.create_type = kw.pop("create_type", True)
super(ENUM, self).__init__(*enums, **kw)
def create(self, bind=None, checkfirst=True):
"""Emit ``CREATE TYPE`` for this
:class:`~.postgresql.ENUM`.
If the underlying dialect does not support
Postgresql CREATE TYPE, no action is taken.
:param bind: a connectable :class:`.Engine`,
:class:`.Connection`, or similar object to emit
SQL.
:param checkfirst: if ``True``, a query against
the PG catalog will be first performed to see
if the type does not exist already before
creating.
"""
if not bind.dialect.supports_native_enum:
return
if not checkfirst or \
not bind.dialect.has_type(bind, self.name, schema=self.schema):
bind.execute(CreateEnumType(self))
def drop(self, bind=None, checkfirst=True):
"""Emit ``DROP TYPE`` for this
:class:`~.postgresql.ENUM`.
If the underlying dialect does not support
Postgresql DROP TYPE, no action is taken.
:param bind: a connectable :class:`.Engine`,
:class:`.Connection`, or similar object to emit
SQL.
:param checkfirst: if ``True``, a query against
the PG catalog will be first performed to see
if the type actually exists before dropping.
"""
if not bind.dialect.supports_native_enum:
return
if not checkfirst or \
bind.dialect.has_type(bind, self.name, schema=self.schema):
bind.execute(DropEnumType(self))
def _check_for_name_in_memos(self, checkfirst, kw):
"""Look in the 'ddl runner' for 'memos', then
note our name in that collection.
This to ensure a particular named enum is operated
upon only once within any kind of create/drop
sequence without relying upon "checkfirst".
"""
if not self.create_type:
return True
if '_ddl_runner' in kw:
ddl_runner = kw['_ddl_runner']
if '_pg_enums' in ddl_runner.memo:
pg_enums = ddl_runner.memo['_pg_enums']
else:
pg_enums = ddl_runner.memo['_pg_enums'] = set()
present = self.name in pg_enums
pg_enums.add(self.name)
return present
else:
return False
def _on_table_create(self, target, bind, checkfirst, **kw):
if not self._check_for_name_in_memos(checkfirst, kw):
self.create(bind=bind, checkfirst=checkfirst)
def _on_metadata_create(self, target, bind, checkfirst, **kw):
if self.metadata is not None and \
not self._check_for_name_in_memos(checkfirst, kw):
self.create(bind=bind, checkfirst=checkfirst)
def _on_metadata_drop(self, target, bind, checkfirst, **kw):
if not self._check_for_name_in_memos(checkfirst, kw):
self.drop(bind=bind, checkfirst=checkfirst)
colspecs = {
sqltypes.Interval: INTERVAL,
sqltypes.Enum: ENUM,
}
ischema_names = {
'integer': INTEGER,
'bigint': BIGINT,
'smallint': SMALLINT,
'character varying': VARCHAR,
'character': CHAR,
'"char"': sqltypes.String,
'name': sqltypes.String,
'text': TEXT,
'numeric': NUMERIC,
'float': FLOAT,
'real': REAL,
'inet': INET,
'cidr': CIDR,
'uuid': UUID,
'bit': BIT,
'bit varying': BIT,
'macaddr': MACADDR,
'double precision': DOUBLE_PRECISION,
'timestamp': TIMESTAMP,
'timestamp with time zone': TIMESTAMP,
'timestamp without time zone': TIMESTAMP,
'time with time zone': TIME,
'time without time zone': TIME,
'date': DATE,
'time': TIME,
'bytea': BYTEA,
'boolean': BOOLEAN,
'interval': INTERVAL,
'interval year to month': INTERVAL,
'interval day to second': INTERVAL,
'tsvector' : TSVECTOR
}
class PGCompiler(compiler.SQLCompiler):
def visit_array(self, element, **kw):
return "ARRAY[%s]" % self.visit_clauselist(element, **kw)
def visit_slice(self, element, **kw):
return "%s:%s" % (
self.process(element.start, **kw),
self.process(element.stop, **kw),
)
def visit_any(self, element, **kw):
return "%s%sANY (%s)" % (
self.process(element.left, **kw),
compiler.OPERATORS[element.operator],
self.process(element.right, **kw)
)
def visit_all(self, element, **kw):
return "%s%sALL (%s)" % (
self.process(element.left, **kw),
compiler.OPERATORS[element.operator],
self.process(element.right, **kw)
)
def visit_getitem_binary(self, binary, operator, **kw):
return "%s[%s]" % (
self.process(binary.left, **kw),
self.process(binary.right, **kw)
)
def visit_match_op_binary(self, binary, operator, **kw):
return "%s @@ to_tsquery(%s)" % (
self.process(binary.left, **kw),
self.process(binary.right, **kw))
def visit_ilike_op_binary(self, binary, operator, **kw):
escape = binary.modifiers.get("escape", None)
return '%s ILIKE %s' % \
(self.process(binary.left, **kw),
self.process(binary.right, **kw)) \
+ (
' ESCAPE ' +
self.render_literal_value(escape, sqltypes.STRINGTYPE)
if escape else ''
)
def visit_notilike_op_binary(self, binary, operator, **kw):
escape = binary.modifiers.get("escape", None)
return '%s NOT ILIKE %s' % \
(self.process(binary.left, **kw),
self.process(binary.right, **kw)) \
+ (
' ESCAPE ' +
self.render_literal_value(escape, sqltypes.STRINGTYPE)
if escape else ''
)
def render_literal_value(self, value, type_):
value = super(PGCompiler, self).render_literal_value(value, type_)
if self.dialect._backslash_escapes:
value = value.replace('\\', '\\\\')
return value
def visit_sequence(self, seq):
return "nextval('%s')" % self.preparer.format_sequence(seq)
def limit_clause(self, select):
text = ""
if select._limit is not None:
text += " \n LIMIT " + self.process(sql.literal(select._limit))
if select._offset is not None:
if select._limit is None:
text += " \n LIMIT ALL"
text += " OFFSET " + self.process(sql.literal(select._offset))
return text
def format_from_hint_text(self, sqltext, table, hint, iscrud):
if hint.upper() != 'ONLY':
raise exc.CompileError("Unrecognized hint: %r" % hint)
return "ONLY " + sqltext
def get_select_precolumns(self, select):
if select._distinct is not False:
if select._distinct is True:
return "DISTINCT "
elif isinstance(select._distinct, (list, tuple)):
return "DISTINCT ON (" + ', '.join(
[self.process(col) for col in select._distinct]
) + ") "
else:
return "DISTINCT ON (" + self.process(select._distinct) + ") "
else:
return ""
def for_update_clause(self, select):
if select._for_update_arg.read:
tmp = " FOR SHARE"
else:
tmp = " FOR UPDATE"
if select._for_update_arg.of:
tables = util.OrderedSet(
c.table if isinstance(c, expression.ColumnClause)
else c for c in select._for_update_arg.of)
tmp += " OF " + ", ".join(
self.process(table, ashint=True)
for table in tables
)
if select._for_update_arg.nowait:
tmp += " NOWAIT"
return tmp
def returning_clause(self, stmt, returning_cols):
columns = [
self._label_select_column(None, c, True, False, {})
for c in expression._select_iterables(returning_cols)
]
return 'RETURNING ' + ', '.join(columns)
def visit_substring_func(self, func, **kw):
s = self.process(func.clauses.clauses[0], **kw)
start = self.process(func.clauses.clauses[1], **kw)
if len(func.clauses.clauses) > 2:
length = self.process(func.clauses.clauses[2], **kw)
return "SUBSTRING(%s FROM %s FOR %s)" % (s, start, length)
else:
return "SUBSTRING(%s FROM %s)" % (s, start)
class PGDDLCompiler(compiler.DDLCompiler):
def get_column_specification(self, column, **kwargs):
colspec = self.preparer.format_column(column)
impl_type = column.type.dialect_impl(self.dialect)
if column.primary_key and \
column is column.table._autoincrement_column and \
(
self.dialect.supports_smallserial or
not isinstance(impl_type, sqltypes.SmallInteger)
) and (
column.default is None or
(
isinstance(column.default, schema.Sequence) and
column.default.optional
)):
if isinstance(impl_type, sqltypes.BigInteger):
colspec += " BIGSERIAL"
elif isinstance(impl_type, sqltypes.SmallInteger):
colspec += " SMALLSERIAL"
else:
colspec += " SERIAL"
else:
colspec += " " + self.dialect.type_compiler.process(column.type)
default = self.get_column_default_string(column)
if default is not None:
colspec += " DEFAULT " + default
if not column.nullable:
colspec += " NOT NULL"
return colspec
def visit_create_enum_type(self, create):
type_ = create.element
return "CREATE TYPE %s AS ENUM (%s)" % (
self.preparer.format_type(type_),
", ".join(
self.sql_compiler.process(sql.literal(e), literal_binds=True)
for e in type_.enums)
)
def visit_drop_enum_type(self, drop):
type_ = drop.element
return "DROP TYPE %s" % (
self.preparer.format_type(type_)
)
def visit_create_index(self, create):
preparer = self.preparer
index = create.element
self._verify_index_table(index)
text = "CREATE "
if index.unique:
text += "UNIQUE "
text += "INDEX %s ON %s " % (
self._prepared_index_name(index,
include_schema=False),
preparer.format_table(index.table)
)
using = index.dialect_options['postgresql']['using']
if using:
text += "USING %s " % preparer.quote(using)
ops = index.dialect_options["postgresql"]["ops"]
text += "(%s)" \
% (
', '.join([
self.sql_compiler.process(
expr.self_group()
if not isinstance(expr, expression.ColumnClause)
else expr,
include_table=False, literal_binds=True) +
(c.key in ops and (' ' + ops[c.key]) or '')
for expr, c in zip(index.expressions, index.columns)])
)
whereclause = index.dialect_options["postgresql"]["where"]
if whereclause is not None:
where_compiled = self.sql_compiler.process(
whereclause, include_table=False,
literal_binds=True)
text += " WHERE " + where_compiled
return text
def visit_exclude_constraint(self, constraint):
text = ""
if constraint.name is not None:
text += "CONSTRAINT %s " % \
self.preparer.format_constraint(constraint)
elements = []
for c in constraint.columns:
op = constraint.operators[c.name]
elements.append(self.preparer.quote(c.name) + ' WITH '+op)
text += "EXCLUDE USING %s (%s)" % (constraint.using, ', '.join(elements))
if constraint.where is not None:
text += ' WHERE (%s)' % self.sql_compiler.process(
constraint.where,
literal_binds=True)
text += self.define_constraint_deferrability(constraint)
return text
class PGTypeCompiler(compiler.GenericTypeCompiler):
def visit_TSVECTOR(self, type):
return "TSVECTOR"
def visit_INET(self, type_):
return "INET"
def visit_CIDR(self, type_):
return "CIDR"
def visit_MACADDR(self, type_):
return "MACADDR"
def visit_FLOAT(self, type_):
if not type_.precision:
return "FLOAT"
else:
return "FLOAT(%(precision)s)" % {'precision': type_.precision}
def visit_DOUBLE_PRECISION(self, type_):
return "DOUBLE PRECISION"
def visit_BIGINT(self, type_):
return "BIGINT"
def visit_HSTORE(self, type_):
return "HSTORE"
def visit_JSON(self, type_):
return "JSON"
def visit_INT4RANGE(self, type_):
return "INT4RANGE"
def visit_INT8RANGE(self, type_):
return "INT8RANGE"
def visit_NUMRANGE(self, type_):
return "NUMRANGE"
def visit_DATERANGE(self, type_):
return "DATERANGE"
def visit_TSRANGE(self, type_):
return "TSRANGE"
def visit_TSTZRANGE(self, type_):
return "TSTZRANGE"
def visit_datetime(self, type_):
return self.visit_TIMESTAMP(type_)
def visit_enum(self, type_):
if not type_.native_enum or not self.dialect.supports_native_enum:
return super(PGTypeCompiler, self).visit_enum(type_)
else:
return self.visit_ENUM(type_)
def visit_ENUM(self, type_):
return self.dialect.identifier_preparer.format_type(type_)
def visit_TIMESTAMP(self, type_):
return "TIMESTAMP%s %s" % (
getattr(type_, 'precision', None) and "(%d)" %
type_.precision or "",
(type_.timezone and "WITH" or "WITHOUT") + " TIME ZONE"
)
def visit_TIME(self, type_):
return "TIME%s %s" % (
getattr(type_, 'precision', None) and "(%d)" %
type_.precision or "",
(type_.timezone and "WITH" or "WITHOUT") + " TIME ZONE"
)
def visit_INTERVAL(self, type_):
if type_.precision is not None:
return "INTERVAL(%d)" % type_.precision
else:
return "INTERVAL"
def visit_BIT(self, type_):
if type_.varying:
compiled = "BIT VARYING"
if type_.length is not None:
compiled += "(%d)" % type_.length
else:
compiled = "BIT(%d)" % type_.length
return compiled
def visit_UUID(self, type_):
return "UUID"
def visit_large_binary(self, type_):
return self.visit_BYTEA(type_)
def visit_BYTEA(self, type_):
return "BYTEA"
def visit_ARRAY(self, type_):
return self.process(type_.item_type) + ('[]' * (type_.dimensions
if type_.dimensions
is not None else 1))
class PGIdentifierPreparer(compiler.IdentifierPreparer):
reserved_words = RESERVED_WORDS
def _unquote_identifier(self, value):
if value[0] == self.initial_quote:
value = value[1:-1].\
replace(self.escape_to_quote, self.escape_quote)
return value
def format_type(self, type_, use_schema=True):
if not type_.name:
raise exc.CompileError("Postgresql ENUM type requires a name.")
name = self.quote(type_.name)
if not self.omit_schema and use_schema and type_.schema is not None:
name = self.quote_schema(type_.schema) + "." + name
return name
class PGInspector(reflection.Inspector):
def __init__(self, conn):
reflection.Inspector.__init__(self, conn)
def get_table_oid(self, table_name, schema=None):
"""Return the oid from `table_name` and `schema`."""
return self.dialect.get_table_oid(self.bind, table_name, schema,
info_cache=self.info_cache)
class CreateEnumType(schema._CreateDropBase):
__visit_name__ = "create_enum_type"
class DropEnumType(schema._CreateDropBase):
__visit_name__ = "drop_enum_type"
class PGExecutionContext(default.DefaultExecutionContext):
def fire_sequence(self, seq, type_):
return self._execute_scalar(("select nextval('%s')" % \
self.dialect.identifier_preparer.format_sequence(seq)), type_)
def get_insert_default(self, column):
if column.primary_key and column is column.table._autoincrement_column:
if column.server_default and column.server_default.has_argument:
# pre-execute passive defaults on primary key columns
return self._execute_scalar("select %s" %
column.server_default.arg, column.type)
elif (column.default is None or
(column.default.is_sequence and
column.default.optional)):
# execute the sequence associated with a SERIAL primary
# key column. for non-primary-key SERIAL, the ID just
# generates server side.
try:
seq_name = column._postgresql_seq_name
except AttributeError:
tab = column.table.name
col = column.name
tab = tab[0:29 + max(0, (29 - len(col)))]
col = col[0:29 + max(0, (29 - len(tab)))]
name = "%s_%s_seq" % (tab, col)
column._postgresql_seq_name = seq_name = name
sch = column.table.schema
if sch is not None:
exc = "select nextval('\"%s\".\"%s\"')" % \
(sch, seq_name)
else:
exc = "select nextval('\"%s\"')" % \
(seq_name, )
return self._execute_scalar(exc, column.type)
return super(PGExecutionContext, self).get_insert_default(column)
class PGDialect(default.DefaultDialect):
name = 'postgresql'
supports_alter = True
max_identifier_length = 63
supports_sane_rowcount = True
supports_native_enum = True
supports_native_boolean = True
supports_smallserial = True
supports_sequences = True
sequences_optional = True
preexecute_autoincrement_sequences = True
postfetch_lastrowid = False
supports_default_values = True
supports_empty_insert = False
supports_multivalues_insert = True
default_paramstyle = 'pyformat'
ischema_names = ischema_names
colspecs = colspecs
statement_compiler = PGCompiler
ddl_compiler = PGDDLCompiler
type_compiler = PGTypeCompiler
preparer = PGIdentifierPreparer
execution_ctx_cls = PGExecutionContext
inspector = PGInspector
isolation_level = None
construct_arguments = [
(schema.Index, {
"using": False,
"where": None,
"ops": {}
}),
(schema.Table, {
"ignore_search_path": False
})
]
reflection_options = ('postgresql_ignore_search_path', )
_backslash_escapes = True
def __init__(self, isolation_level=None, json_serializer=None,
json_deserializer=None, **kwargs):
default.DefaultDialect.__init__(self, **kwargs)
self.isolation_level = isolation_level
self._json_deserializer = json_deserializer
self._json_serializer = json_serializer
def initialize(self, connection):
super(PGDialect, self).initialize(connection)
self.implicit_returning = self.server_version_info > (8, 2) and \
self.__dict__.get('implicit_returning', True)
self.supports_native_enum = self.server_version_info >= (8, 3)
if not self.supports_native_enum:
self.colspecs = self.colspecs.copy()
# pop base Enum type
self.colspecs.pop(sqltypes.Enum, None)
# psycopg2, others may have placed ENUM here as well
self.colspecs.pop(ENUM, None)
# http://www.postgresql.org/docs/9.3/static/release-9-2.html#AEN116689
self.supports_smallserial = self.server_version_info >= (9, 2)
self._backslash_escapes = self.server_version_info < (8, 2) or \
connection.scalar(
"show standard_conforming_strings"
) == 'off'
def on_connect(self):
if self.isolation_level is not None:
def connect(conn):
self.set_isolation_level(conn, self.isolation_level)
return connect
else:
return None
_isolation_lookup = set(['SERIALIZABLE',
'READ UNCOMMITTED', 'READ COMMITTED', 'REPEATABLE READ'])
def set_isolation_level(self, connection, level):
level = level.replace('_', ' ')
if level not in self._isolation_lookup:
raise exc.ArgumentError(
"Invalid value '%s' for isolation_level. "
"Valid isolation levels for %s are %s" %
(level, self.name, ", ".join(self._isolation_lookup))
)
cursor = connection.cursor()
cursor.execute(
"SET SESSION CHARACTERISTICS AS TRANSACTION "
"ISOLATION LEVEL %s" % level)
cursor.execute("COMMIT")
cursor.close()
def get_isolation_level(self, connection):
cursor = connection.cursor()
cursor.execute('show transaction isolation level')
val = cursor.fetchone()[0]
cursor.close()
return val.upper()
def do_begin_twophase(self, connection, xid):
self.do_begin(connection.connection)
def do_prepare_twophase(self, connection, xid):
connection.execute("PREPARE TRANSACTION '%s'" % xid)
def do_rollback_twophase(self, connection, xid,
is_prepared=True, recover=False):
if is_prepared:
if recover:
#FIXME: ugly hack to get out of transaction
# context when committing recoverable transactions
# Must find out a way how to make the dbapi not
# open a transaction.
connection.execute("ROLLBACK")
connection.execute("ROLLBACK PREPARED '%s'" % xid)
connection.execute("BEGIN")
self.do_rollback(connection.connection)
else:
self.do_rollback(connection.connection)
def do_commit_twophase(self, connection, xid,
is_prepared=True, recover=False):
if is_prepared:
if recover:
connection.execute("ROLLBACK")
connection.execute("COMMIT PREPARED '%s'" % xid)
connection.execute("BEGIN")
self.do_rollback(connection.connection)
else:
self.do_commit(connection.connection)
def do_recover_twophase(self, connection):
resultset = connection.execute(
sql.text("SELECT gid FROM pg_prepared_xacts"))
return [row[0] for row in resultset]
def _get_default_schema_name(self, connection):
return connection.scalar("select current_schema()")
def has_schema(self, connection, schema):
query = "select nspname from pg_namespace where lower(nspname)=:schema"
cursor = connection.execute(
sql.text(
query,
bindparams=[
sql.bindparam(
'schema', util.text_type(schema.lower()),
type_=sqltypes.Unicode)]
)
)
return bool(cursor.first())
def has_table(self, connection, table_name, schema=None):
# seems like case gets folded in pg_class...
if schema is None:
cursor = connection.execute(
sql.text(
"select relname from pg_class c join pg_namespace n on "
"n.oid=c.relnamespace where n.nspname=current_schema() and "
"relname=:name",
bindparams=[
sql.bindparam('name', util.text_type(table_name),
type_=sqltypes.Unicode)]
)
)
else:
cursor = connection.execute(
sql.text(
"select relname from pg_class c join pg_namespace n on "
"n.oid=c.relnamespace where n.nspname=:schema and "
"relname=:name",
bindparams=[
sql.bindparam('name',
util.text_type(table_name), type_=sqltypes.Unicode),
sql.bindparam('schema',
util.text_type(schema), type_=sqltypes.Unicode)]
)
)
return bool(cursor.first())
def has_sequence(self, connection, sequence_name, schema=None):
if schema is None:
cursor = connection.execute(
sql.text(
"SELECT relname FROM pg_class c join pg_namespace n on "
"n.oid=c.relnamespace where relkind='S' and "
"n.nspname=current_schema() "
"and relname=:name",
bindparams=[
sql.bindparam('name', util.text_type(sequence_name),
type_=sqltypes.Unicode)
]
)
)
else:
cursor = connection.execute(
sql.text(
"SELECT relname FROM pg_class c join pg_namespace n on "
"n.oid=c.relnamespace where relkind='S' and "
"n.nspname=:schema and relname=:name",
bindparams=[
sql.bindparam('name', util.text_type(sequence_name),
type_=sqltypes.Unicode),
sql.bindparam('schema',
util.text_type(schema), type_=sqltypes.Unicode)
]
)
)
return bool(cursor.first())
def has_type(self, connection, type_name, schema=None):
if schema is not None:
query = """
SELECT EXISTS (
SELECT * FROM pg_catalog.pg_type t, pg_catalog.pg_namespace n
WHERE t.typnamespace = n.oid
AND t.typname = :typname
AND n.nspname = :nspname
)
"""
query = sql.text(query)
else:
query = """
SELECT EXISTS (
SELECT * FROM pg_catalog.pg_type t
WHERE t.typname = :typname
AND pg_type_is_visible(t.oid)
)
"""
query = sql.text(query)
query = query.bindparams(
sql.bindparam('typname',
util.text_type(type_name), type_=sqltypes.Unicode),
)
if schema is not None:
query = query.bindparams(
sql.bindparam('nspname',
util.text_type(schema), type_=sqltypes.Unicode),
)
cursor = connection.execute(query)
return bool(cursor.scalar())
def _get_server_version_info(self, connection):
v = connection.execute("select version()").scalar()
m = re.match(
'.*(?:PostgreSQL|EnterpriseDB) '
'(\d+)\.(\d+)(?:\.(\d+))?(?:\.\d+)?(?:devel)?',
v)
if not m:
raise AssertionError(
"Could not determine version from string '%s'" % v)
return tuple([int(x) for x in m.group(1, 2, 3) if x is not None])
@reflection.cache
def get_table_oid(self, connection, table_name, schema=None, **kw):
"""Fetch the oid for schema.table_name.
Several reflection methods require the table oid. The idea for using
this method is that it can be fetched one time and cached for
subsequent calls.
"""
table_oid = None
if schema is not None:
schema_where_clause = "n.nspname = :schema"
else:
schema_where_clause = "pg_catalog.pg_table_is_visible(c.oid)"
query = """
SELECT c.oid
FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE (%s)
AND c.relname = :table_name AND c.relkind in ('r','v')
""" % schema_where_clause
# Since we're binding to unicode, table_name and schema_name must be
# unicode.
table_name = util.text_type(table_name)
if schema is not None:
schema = util.text_type(schema)
s = sql.text(query).bindparams(table_name=sqltypes.Unicode)
s = s.columns(oid=sqltypes.Integer)
if schema:
s = s.bindparams(sql.bindparam('schema', type_=sqltypes.Unicode))
c = connection.execute(s, table_name=table_name, schema=schema)
table_oid = c.scalar()
if table_oid is None:
raise exc.NoSuchTableError(table_name)
return table_oid
@reflection.cache
def get_schema_names(self, connection, **kw):
s = """
SELECT nspname
FROM pg_namespace
ORDER BY nspname
"""
rp = connection.execute(s)
# what about system tables?
if util.py2k:
schema_names = [row[0].decode(self.encoding) for row in rp \
if not row[0].startswith('pg_')]
else:
schema_names = [row[0] for row in rp \
if not row[0].startswith('pg_')]
return schema_names
@reflection.cache
def get_table_names(self, connection, schema=None, **kw):
if schema is not None:
current_schema = schema
else:
current_schema = self.default_schema_name
result = connection.execute(
sql.text("SELECT relname FROM pg_class c "
"WHERE relkind = 'r' "
"AND '%s' = (select nspname from pg_namespace n "
"where n.oid = c.relnamespace) " %
current_schema,
typemap={'relname': sqltypes.Unicode}
)
)
return [row[0] for row in result]
@reflection.cache
def get_view_names(self, connection, schema=None, **kw):
if schema is not None:
current_schema = schema
else:
current_schema = self.default_schema_name
s = """
SELECT relname
FROM pg_class c
WHERE relkind = 'v'
AND '%(schema)s' = (select nspname from pg_namespace n
where n.oid = c.relnamespace)
""" % dict(schema=current_schema)
if util.py2k:
view_names = [row[0].decode(self.encoding)
for row in connection.execute(s)]
else:
view_names = [row[0] for row in connection.execute(s)]
return view_names
@reflection.cache
def get_view_definition(self, connection, view_name, schema=None, **kw):
if schema is not None:
current_schema = schema
else:
current_schema = self.default_schema_name
s = """
SELECT definition FROM pg_views
WHERE schemaname = :schema
AND viewname = :view_name
"""
rp = connection.execute(sql.text(s),
view_name=view_name, schema=current_schema)
if rp:
if util.py2k:
view_def = rp.scalar().decode(self.encoding)
else:
view_def = rp.scalar()
return view_def
@reflection.cache
def get_columns(self, connection, table_name, schema=None, **kw):
table_oid = self.get_table_oid(connection, table_name, schema,
info_cache=kw.get('info_cache'))
SQL_COLS = """
SELECT a.attname,
pg_catalog.format_type(a.atttypid, a.atttypmod),
(SELECT pg_catalog.pg_get_expr(d.adbin, d.adrelid)
FROM pg_catalog.pg_attrdef d
WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum
AND a.atthasdef)
AS DEFAULT,
a.attnotnull, a.attnum, a.attrelid as table_oid
FROM pg_catalog.pg_attribute a
WHERE a.attrelid = :table_oid
AND a.attnum > 0 AND NOT a.attisdropped
ORDER BY a.attnum
"""
s = sql.text(SQL_COLS,
bindparams=[sql.bindparam('table_oid', type_=sqltypes.Integer)],
typemap={'attname': sqltypes.Unicode, 'default': sqltypes.Unicode}
)
c = connection.execute(s, table_oid=table_oid)
rows = c.fetchall()
domains = self._load_domains(connection)
enums = self._load_enums(connection)
# format columns
columns = []
for name, format_type, default, notnull, attnum, table_oid in rows:
column_info = self._get_column_info(
name, format_type, default, notnull, domains, enums, schema)
columns.append(column_info)
return columns
def _get_column_info(self, name, format_type, default,
notnull, domains, enums, schema):
## strip (*) from character varying(5), timestamp(5)
# with time zone, geometry(POLYGON), etc.
attype = re.sub(r'\(.*\)', '', format_type)
# strip '[]' from integer[], etc.
attype = re.sub(r'\[\]', '', attype)
nullable = not notnull
is_array = format_type.endswith('[]')
charlen = re.search('\(([\d,]+)\)', format_type)
if charlen:
charlen = charlen.group(1)
args = re.search('\((.*)\)', format_type)
if args and args.group(1):
args = tuple(re.split('\s*,\s*', args.group(1)))
else:
args = ()
kwargs = {}
if attype == 'numeric':
if charlen:
prec, scale = charlen.split(',')
args = (int(prec), int(scale))
else:
args = ()
elif attype == 'double precision':
args = (53, )
elif attype == 'integer':
args = ()
elif attype in ('timestamp with time zone',
'time with time zone'):
kwargs['timezone'] = True
if charlen:
kwargs['precision'] = int(charlen)
args = ()
elif attype in ('timestamp without time zone',
'time without time zone', 'time'):
kwargs['timezone'] = False
if charlen:
kwargs['precision'] = int(charlen)
args = ()
elif attype == 'bit varying':
kwargs['varying'] = True
if charlen:
args = (int(charlen),)
else:
args = ()
elif attype in ('interval', 'interval year to month',
'interval day to second'):
if charlen:
kwargs['precision'] = int(charlen)
args = ()
elif charlen:
args = (int(charlen),)
while True:
if attype in self.ischema_names:
coltype = self.ischema_names[attype]
break
elif attype in enums:
enum = enums[attype]
coltype = ENUM
if "." in attype:
kwargs['schema'], kwargs['name'] = attype.split('.')
else:
kwargs['name'] = attype
args = tuple(enum['labels'])
break
elif attype in domains:
domain = domains[attype]
attype = domain['attype']
# A table can't override whether the domain is nullable.
nullable = domain['nullable']
if domain['default'] and not default:
# It can, however, override the default
# value, but can't set it to null.
default = domain['default']
continue
else:
coltype = None
break
if coltype:
coltype = coltype(*args, **kwargs)
if is_array:
coltype = ARRAY(coltype)
else:
util.warn("Did not recognize type '%s' of column '%s'" %
(attype, name))
coltype = sqltypes.NULLTYPE
# adjust the default value
autoincrement = False
if default is not None:
match = re.search(r"""(nextval\(')([^']+)('.*$)""", default)
if match is not None:
autoincrement = True
# the default is related to a Sequence
sch = schema
if '.' not in match.group(2) and sch is not None:
# unconditionally quote the schema name. this could
# later be enhanced to obey quoting rules /
# "quote schema"
default = match.group(1) + \
('"%s"' % sch) + '.' + \
match.group(2) + match.group(3)
column_info = dict(name=name, type=coltype, nullable=nullable,
default=default, autoincrement=autoincrement)
return column_info
@reflection.cache
def get_pk_constraint(self, connection, table_name, schema=None, **kw):
table_oid = self.get_table_oid(connection, table_name, schema,
info_cache=kw.get('info_cache'))
if self.server_version_info < (8, 4):
PK_SQL = """
SELECT a.attname
FROM
pg_class t
join pg_index ix on t.oid = ix.indrelid
join pg_attribute a
on t.oid=a.attrelid AND %s
WHERE
t.oid = :table_oid and ix.indisprimary = 't'
ORDER BY a.attnum
""" % self._pg_index_any("a.attnum", "ix.indkey")
else:
# unnest() and generate_subscripts() both introduced in
# version 8.4
PK_SQL = """
SELECT a.attname
FROM pg_attribute a JOIN (
SELECT unnest(ix.indkey) attnum,
generate_subscripts(ix.indkey, 1) ord
FROM pg_index ix
WHERE ix.indrelid = :table_oid AND ix.indisprimary
) k ON a.attnum=k.attnum
WHERE a.attrelid = :table_oid
ORDER BY k.ord
"""
t = sql.text(PK_SQL, typemap={'attname': sqltypes.Unicode})
c = connection.execute(t, table_oid=table_oid)
cols = [r[0] for r in c.fetchall()]
PK_CONS_SQL = """
SELECT conname
FROM pg_catalog.pg_constraint r
WHERE r.conrelid = :table_oid AND r.contype = 'p'
ORDER BY 1
"""
t = sql.text(PK_CONS_SQL, typemap={'conname': sqltypes.Unicode})
c = connection.execute(t, table_oid=table_oid)
name = c.scalar()
return {'constrained_columns': cols, 'name': name}
@reflection.cache
def get_foreign_keys(self, connection, table_name, schema=None,
postgresql_ignore_search_path=False, **kw):
preparer = self.identifier_preparer
table_oid = self.get_table_oid(connection, table_name, schema,
info_cache=kw.get('info_cache'))
FK_SQL = """
SELECT r.conname,
pg_catalog.pg_get_constraintdef(r.oid, true) as condef,
n.nspname as conschema
FROM pg_catalog.pg_constraint r,
pg_namespace n,
pg_class c
WHERE r.conrelid = :table AND
r.contype = 'f' AND
c.oid = confrelid AND
n.oid = c.relnamespace
ORDER BY 1
"""
# http://www.postgresql.org/docs/9.0/static/sql-createtable.html
FK_REGEX = re.compile(
r'FOREIGN KEY \((.*?)\) REFERENCES (?:(.*?)\.)?(.*?)\((.*?)\)'
r'[\s]?(MATCH (FULL|PARTIAL|SIMPLE)+)?'
r'[\s]?(ON UPDATE (CASCADE|RESTRICT|NO ACTION|SET NULL|SET DEFAULT)+)?'
r'[\s]?(ON DELETE (CASCADE|RESTRICT|NO ACTION|SET NULL|SET DEFAULT)+)?'
r'[\s]?(DEFERRABLE|NOT DEFERRABLE)?'
r'[\s]?(INITIALLY (DEFERRED|IMMEDIATE)+)?'
)
t = sql.text(FK_SQL, typemap={
'conname': sqltypes.Unicode,
'condef': sqltypes.Unicode})
c = connection.execute(t, table=table_oid)
fkeys = []
for conname, condef, conschema in c.fetchall():
m = re.search(FK_REGEX, condef).groups()
constrained_columns, referred_schema, \
referred_table, referred_columns, \
_, match, _, onupdate, _, ondelete, \
deferrable, _, initially = m
if deferrable is not None:
deferrable = True if deferrable == 'DEFERRABLE' else False
constrained_columns = [preparer._unquote_identifier(x)
for x in re.split(r'\s*,\s*', constrained_columns)]
if postgresql_ignore_search_path:
# when ignoring search path, we use the actual schema
# provided it isn't the "default" schema
if conschema != self.default_schema_name:
referred_schema = conschema
else:
referred_schema = schema
elif referred_schema:
# referred_schema is the schema that we regexp'ed from
# pg_get_constraintdef(). If the schema is in the search
# path, pg_get_constraintdef() will give us None.
referred_schema = \
preparer._unquote_identifier(referred_schema)
elif schema is not None and schema == conschema:
# If the actual schema matches the schema of the table
# we're reflecting, then we will use that.
referred_schema = schema
referred_table = preparer._unquote_identifier(referred_table)
referred_columns = [preparer._unquote_identifier(x)
for x in re.split(r'\s*,\s', referred_columns)]
fkey_d = {
'name': conname,
'constrained_columns': constrained_columns,
'referred_schema': referred_schema,
'referred_table': referred_table,
'referred_columns': referred_columns,
'options': {
'onupdate': onupdate,
'ondelete': ondelete,
'deferrable': deferrable,
'initially': initially,
'match': match
}
}
fkeys.append(fkey_d)
return fkeys
def _pg_index_any(self, col, compare_to):
if self.server_version_info < (8, 1):
# http://www.postgresql.org/message-id/10279.1124395722@sss.pgh.pa.us
# "In CVS tip you could replace this with "attnum = ANY (indkey)".
# Unfortunately, most array support doesn't work on int2vector in
# pre-8.1 releases, so I think you're kinda stuck with the above
# for now.
# regards, tom lane"
return "(%s)" % " OR ".join(
"%s[%d] = %s" % (compare_to, ind, col)
for ind in range(0, 10)
)
else:
return "%s = ANY(%s)" % (col, compare_to)
@reflection.cache
def get_indexes(self, connection, table_name, schema, **kw):
table_oid = self.get_table_oid(connection, table_name, schema,
info_cache=kw.get('info_cache'))
# cast indkey as varchar since it's an int2vector,
# returned as a list by some drivers such as pypostgresql
IDX_SQL = """
SELECT
i.relname as relname,
ix.indisunique, ix.indexprs, ix.indpred,
a.attname, a.attnum, ix.indkey%s
FROM
pg_class t
join pg_index ix on t.oid = ix.indrelid
join pg_class i on i.oid=ix.indexrelid
left outer join
pg_attribute a
on t.oid=a.attrelid and %s
WHERE
t.relkind = 'r'
and t.oid = :table_oid
and ix.indisprimary = 'f'
ORDER BY
t.relname,
i.relname
""" % (
# version 8.3 here was based on observing the
# cast does not work in PG 8.2.4, does work in 8.3.0.
# nothing in PG changelogs regarding this.
"::varchar" if self.server_version_info >= (8, 3) else "",
self._pg_index_any("a.attnum", "ix.indkey")
)
t = sql.text(IDX_SQL, typemap={'attname': sqltypes.Unicode})
c = connection.execute(t, table_oid=table_oid)
indexes = defaultdict(lambda: defaultdict(dict))
sv_idx_name = None
for row in c.fetchall():
idx_name, unique, expr, prd, col, col_num, idx_key = row
if expr:
if idx_name != sv_idx_name:
util.warn(
"Skipped unsupported reflection of "
"expression-based index %s"
% idx_name)
sv_idx_name = idx_name
continue
if prd and not idx_name == sv_idx_name:
util.warn(
"Predicate of partial index %s ignored during reflection"
% idx_name)
sv_idx_name = idx_name
index = indexes[idx_name]
if col is not None:
index['cols'][col_num] = col
index['key'] = [int(k.strip()) for k in idx_key.split()]
index['unique'] = unique
return [
{'name': name,
'unique': idx['unique'],
'column_names': [idx['cols'][i] for i in idx['key']]}
for name, idx in indexes.items()
]
@reflection.cache
def get_unique_constraints(self, connection, table_name,
schema=None, **kw):
table_oid = self.get_table_oid(connection, table_name, schema,
info_cache=kw.get('info_cache'))
UNIQUE_SQL = """
SELECT
cons.conname as name,
cons.conkey as key,
a.attnum as col_num,
a.attname as col_name
FROM
pg_catalog.pg_constraint cons
join pg_attribute a
on cons.conrelid = a.attrelid AND a.attnum = ANY(cons.conkey)
WHERE
cons.conrelid = :table_oid AND
cons.contype = 'u'
"""
t = sql.text(UNIQUE_SQL, typemap={'col_name': sqltypes.Unicode})
c = connection.execute(t, table_oid=table_oid)
uniques = defaultdict(lambda: defaultdict(dict))
for row in c.fetchall():
uc = uniques[row.name]
uc["key"] = row.key
uc["cols"][row.col_num] = row.col_name
return [
{'name': name,
'column_names': [uc["cols"][i] for i in uc["key"]]}
for name, uc in uniques.items()
]
def _load_enums(self, connection):
if not self.supports_native_enum:
return {}
## Load data types for enums:
SQL_ENUMS = """
SELECT t.typname as "name",
-- no enum defaults in 8.4 at least
-- t.typdefault as "default",
pg_catalog.pg_type_is_visible(t.oid) as "visible",
n.nspname as "schema",
e.enumlabel as "label"
FROM pg_catalog.pg_type t
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = t.typnamespace
LEFT JOIN pg_catalog.pg_enum e ON t.oid = e.enumtypid
WHERE t.typtype = 'e'
ORDER BY "name", e.oid -- e.oid gives us label order
"""
s = sql.text(SQL_ENUMS, typemap={
'attname': sqltypes.Unicode,
'label': sqltypes.Unicode})
c = connection.execute(s)
enums = {}
for enum in c.fetchall():
if enum['visible']:
# 'visible' just means whether or not the enum is in a
# schema that's on the search path -- or not overridden by
# a schema with higher precedence. If it's not visible,
# it will be prefixed with the schema-name when it's used.
name = enum['name']
else:
name = "%s.%s" % (enum['schema'], enum['name'])
if name in enums:
enums[name]['labels'].append(enum['label'])
else:
enums[name] = {
'labels': [enum['label']],
}
return enums
def _load_domains(self, connection):
## Load data types for domains:
SQL_DOMAINS = """
SELECT t.typname as "name",
pg_catalog.format_type(t.typbasetype, t.typtypmod) as "attype",
not t.typnotnull as "nullable",
t.typdefault as "default",
pg_catalog.pg_type_is_visible(t.oid) as "visible",
n.nspname as "schema"
FROM pg_catalog.pg_type t
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = t.typnamespace
WHERE t.typtype = 'd'
"""
s = sql.text(SQL_DOMAINS, typemap={'attname': sqltypes.Unicode})
c = connection.execute(s)
domains = {}
for domain in c.fetchall():
## strip (30) from character varying(30)
attype = re.search('([^\(]+)', domain['attype']).group(1)
if domain['visible']:
# 'visible' just means whether or not the domain is in a
# schema that's on the search path -- or not overridden by
# a schema with higher precedence. If it's not visible,
# it will be prefixed with the schema-name when it's used.
name = domain['name']
else:
name = "%s.%s" % (domain['schema'], domain['name'])
domains[name] = {
'attype': attype,
'nullable': domain['nullable'],
'default': domain['default']
}
return domains
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