Viewing file:  postgresql.py (5.2 KB) -rw-r--r--
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import re
from ..util import compat
from .. import util
from .base import compiles, alter_table, format_table_name, RenameTable
from .impl import DefaultImpl
from sqlalchemy.dialects.postgresql import INTEGER, BIGINT
from sqlalchemy import text, Numeric, Column
if compat.sqla_08:
from sqlalchemy.sql.expression import UnaryExpression
else:
from sqlalchemy.sql.expression import _UnaryExpression as UnaryExpression
import logging
log = logging.getLogger(__name__)
class PostgresqlImpl(DefaultImpl):
__dialect__ = 'postgresql'
transactional_ddl = True
def prep_table_for_batch(self, table):
for constraint in table.constraints:
if constraint.name is not None:
self.drop_constraint(constraint)
def compare_server_default(self, inspector_column,
metadata_column,
rendered_metadata_default,
rendered_inspector_default):
# don't do defaults for SERIAL columns
if metadata_column.primary_key and \
metadata_column is metadata_column.table._autoincrement_column:
return False
conn_col_default = rendered_inspector_default
if None in (conn_col_default, rendered_metadata_default):
return conn_col_default != rendered_metadata_default
if metadata_column.server_default is not None and \
isinstance(metadata_column.server_default.arg,
compat.string_types) and \
not re.match(r"^'.+'$", rendered_metadata_default) and \
not isinstance(inspector_column.type, Numeric):
# don't single quote if the column type is float/numeric,
# otherwise a comparison such as SELECT 5 = '5.0' will fail
rendered_metadata_default = re.sub(
r"^u?'?|'?$", "'", rendered_metadata_default)
return not self.connection.scalar(
"SELECT %s = %s" % (
conn_col_default,
rendered_metadata_default
)
)
def autogen_column_reflect(self, inspector, table, column_info):
if column_info.get('default') and \
isinstance(column_info['type'], (INTEGER, BIGINT)):
seq_match = re.match(
r"nextval\('(.+?)'::regclass\)",
column_info['default'])
if seq_match:
info = inspector.bind.execute(text(
"select c.relname, a.attname "
"from pg_class as c join pg_depend d on d.objid=c.oid and "
"d.classid='pg_class'::regclass and "
"d.refclassid='pg_class'::regclass "
"join pg_class t on t.oid=d.refobjid "
"join pg_attribute a on a.attrelid=t.oid and "
"a.attnum=d.refobjsubid "
"where c.relkind='S' and c.relname=:seqname"
), seqname=seq_match.group(1)).first()
if info:
seqname, colname = info
if colname == column_info['name']:
log.info(
"Detected sequence named '%s' as "
"owned by integer column '%s(%s)', "
"assuming SERIAL and omitting" % (
seqname, table.name, colname
))
# sequence, and the owner is this column,
# its a SERIAL - whack it!
del column_info['default']
def correct_for_autogen_constraints(self, conn_unique_constraints,
conn_indexes,
metadata_unique_constraints,
metadata_indexes):
conn_uniques_by_name = dict(
(c.name, c) for c in conn_unique_constraints)
conn_indexes_by_name = dict(
(c.name, c) for c in conn_indexes)
# TODO: if SQLA 1.0, make use of "duplicates_constraint"
# metadata
doubled_constraints = dict(
(name, (conn_uniques_by_name[name], conn_indexes_by_name[name]))
for name in set(conn_uniques_by_name).intersection(
conn_indexes_by_name)
)
for name, (uq, ix) in doubled_constraints.items():
conn_indexes.remove(ix)
for idx in list(metadata_indexes):
if idx.name in conn_indexes_by_name:
continue
if compat.sqla_08:
exprs = idx.expressions
else:
exprs = idx.columns
for expr in exprs:
if not isinstance(expr, (Column, UnaryExpression)):
util.warn(
"autogenerate skipping functional index %s; "
"not supported by SQLAlchemy reflection" % idx.name
)
metadata_indexes.discard(idx)
@compiles(RenameTable, "postgresql")
def visit_rename_table(element, compiler, **kw):
return "%s RENAME TO %s" % (
alter_table(compiler, element.table_name, element.schema),
format_table_name(compiler, element.new_table_name, None)
)
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