307 lines
11 KiB
Python
307 lines
11 KiB
Python
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# informix.py
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# Copyright (C) 2005,2006, 2007, 2008, 2009, 2010 Michael Bayer mike_mp@zzzcomputing.com
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#
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# coding: gbk
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: http://www.opensource.org/licenses/mit-license.php
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"""Support for the Informix database.
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This dialect is *not* tested on SQLAlchemy 0.6.
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"""
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import datetime
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from sqlalchemy import sql, schema, exc, pool, util
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from sqlalchemy.sql import compiler
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from sqlalchemy.engine import default, reflection
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from sqlalchemy import types as sqltypes
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class InfoDateTime(sqltypes.DateTime):
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def bind_processor(self, dialect):
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def process(value):
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if value is not None:
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if value.microsecond:
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value = value.replace(microsecond=0)
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return value
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return process
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class InfoTime(sqltypes.Time):
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def bind_processor(self, dialect):
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def process(value):
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if value is not None:
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if value.microsecond:
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value = value.replace(microsecond=0)
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return value
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return process
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def result_processor(self, dialect, coltype):
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def process(value):
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if isinstance(value, datetime.datetime):
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return value.time()
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else:
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return value
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return process
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colspecs = {
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sqltypes.DateTime : InfoDateTime,
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sqltypes.Time: InfoTime,
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}
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ischema_names = {
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0 : sqltypes.CHAR, # CHAR
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1 : sqltypes.SMALLINT, # SMALLINT
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2 : sqltypes.INTEGER, # INT
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3 : sqltypes.FLOAT, # Float
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3 : sqltypes.Float, # SmallFloat
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5 : sqltypes.DECIMAL, # DECIMAL
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6 : sqltypes.Integer, # Serial
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7 : sqltypes.DATE, # DATE
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8 : sqltypes.Numeric, # MONEY
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10 : sqltypes.DATETIME, # DATETIME
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11 : sqltypes.LargeBinary, # BYTE
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12 : sqltypes.TEXT, # TEXT
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13 : sqltypes.VARCHAR, # VARCHAR
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15 : sqltypes.NCHAR, # NCHAR
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16 : sqltypes.NVARCHAR, # NVARCHAR
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17 : sqltypes.Integer, # INT8
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18 : sqltypes.Integer, # Serial8
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43 : sqltypes.String, # LVARCHAR
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-1 : sqltypes.BLOB, # BLOB
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-1 : sqltypes.CLOB, # CLOB
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}
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class InfoTypeCompiler(compiler.GenericTypeCompiler):
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def visit_DATETIME(self, type_):
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return "DATETIME YEAR TO SECOND"
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def visit_TIME(self, type_):
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return "DATETIME HOUR TO SECOND"
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def visit_large_binary(self, type_):
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return "BYTE"
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def visit_boolean(self, type_):
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return "SMALLINT"
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class InfoSQLCompiler(compiler.SQLCompiler):
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def default_from(self):
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return " from systables where tabname = 'systables' "
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def get_select_precolumns(self, select):
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s = select._distinct and "DISTINCT " or ""
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# only has limit
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if select._limit:
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s += " FIRST %s " % select._limit
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else:
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s += ""
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return s
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def visit_select(self, select):
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# the column in order by clause must in select too
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def __label(c):
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try:
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return c._label.lower()
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except:
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return ''
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# TODO: dont modify the original select, generate a new one
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a = [__label(c) for c in select._raw_columns]
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for c in select._order_by_clause.clauses:
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if __label(c) not in a:
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select.append_column(c)
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return compiler.SQLCompiler.visit_select(self, select)
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def limit_clause(self, select):
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if select._offset is not None and select._offset > 0:
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raise NotImplementedError("Informix does not support OFFSET")
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return ""
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def visit_function(self, func):
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if func.name.lower() == 'current_date':
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return "today"
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elif func.name.lower() == 'current_time':
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return "CURRENT HOUR TO SECOND"
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elif func.name.lower() in ('current_timestamp', 'now'):
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return "CURRENT YEAR TO SECOND"
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else:
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return compiler.SQLCompiler.visit_function(self, func)
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class InfoDDLCompiler(compiler.DDLCompiler):
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def get_column_specification(self, column, first_pk=False):
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colspec = self.preparer.format_column(column)
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if column.primary_key and len(column.foreign_keys)==0 and column.autoincrement and \
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isinstance(column.type, sqltypes.Integer) and first_pk:
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colspec += " SERIAL"
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else:
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colspec += " " + self.dialect.type_compiler.process(column.type)
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default = self.get_column_default_string(column)
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if default is not None:
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colspec += " DEFAULT " + default
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if not column.nullable:
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colspec += " NOT NULL"
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return colspec
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class InfoIdentifierPreparer(compiler.IdentifierPreparer):
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def __init__(self, dialect):
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super(InfoIdentifierPreparer, self).__init__(dialect, initial_quote="'")
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def format_constraint(self, constraint):
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# informix doesnt support names for constraints
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return ''
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def _requires_quotes(self, value):
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return False
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class InformixDialect(default.DefaultDialect):
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name = 'informix'
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max_identifier_length = 128 # adjusts at runtime based on server version
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type_compiler = InfoTypeCompiler
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statement_compiler = InfoSQLCompiler
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ddl_compiler = InfoDDLCompiler
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preparer = InfoIdentifierPreparer
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colspecs = colspecs
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ischema_names = ischema_names
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def initialize(self, connection):
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super(InformixDialect, self).initialize(connection)
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# http://www.querix.com/support/knowledge-base/error_number_message/error_200
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if self.server_version_info < (9, 2):
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self.max_identifier_length = 18
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else:
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self.max_identifier_length = 128
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def do_begin(self, connect):
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cu = connect.cursor()
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cu.execute('SET LOCK MODE TO WAIT')
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#cu.execute('SET ISOLATION TO REPEATABLE READ')
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@reflection.cache
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def get_table_names(self, connection, schema=None, **kw):
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s = "select tabname from systables"
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return [row[0] for row in connection.execute(s)]
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def has_table(self, connection, table_name, schema=None):
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cursor = connection.execute("""select tabname from systables where tabname=?""", table_name.lower())
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return cursor.first() is not None
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@reflection.cache
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def get_columns(self, connection, table_name, schema=None, **kw):
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c = connection.execute ("""select colname , coltype , collength , t3.default , t1.colno from
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syscolumns as t1 , systables as t2 , OUTER sysdefaults as t3
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where t1.tabid = t2.tabid and t2.tabname=?
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and t3.tabid = t2.tabid and t3.colno = t1.colno
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order by t1.colno""", table.name.lower())
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columns = []
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for name, colattr, collength, default, colno in rows:
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name = name.lower()
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if include_columns and name not in include_columns:
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continue
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# in 7.31, coltype = 0x000
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# ^^-- column type
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# ^-- 1 not null, 0 null
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nullable, coltype = divmod(colattr, 256)
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if coltype not in (0, 13) and default:
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default = default.split()[-1]
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if coltype == 0 or coltype == 13: # char, varchar
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coltype = ischema_names[coltype](collength)
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if default:
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default = "'%s'" % default
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elif coltype == 5: # decimal
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precision, scale = (collength & 0xFF00) >> 8, collength & 0xFF
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if scale == 255:
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scale = 0
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coltype = sqltypes.Numeric(precision, scale)
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else:
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try:
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coltype = ischema_names[coltype]
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except KeyError:
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util.warn("Did not recognize type '%s' of column '%s'" %
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(coltype, name))
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coltype = sqltypes.NULLTYPE
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# TODO: nullability ??
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nullable = True
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column_info = dict(name=name, type=coltype, nullable=nullable,
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default=default)
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columns.append(column_info)
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return columns
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@reflection.cache
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def get_foreign_keys(self, connection, table_name, schema=None, **kw):
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# FK
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c = connection.execute("""select t1.constrname as cons_name , t1.constrtype as cons_type ,
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t4.colname as local_column , t7.tabname as remote_table ,
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t6.colname as remote_column
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from sysconstraints as t1 , systables as t2 ,
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sysindexes as t3 , syscolumns as t4 ,
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sysreferences as t5 , syscolumns as t6 , systables as t7 ,
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sysconstraints as t8 , sysindexes as t9
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where t1.tabid = t2.tabid and t2.tabname=? and t1.constrtype = 'R'
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and t3.tabid = t2.tabid and t3.idxname = t1.idxname
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and t4.tabid = t2.tabid and t4.colno = t3.part1
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and t5.constrid = t1.constrid and t8.constrid = t5.primary
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and t6.tabid = t5.ptabid and t6.colno = t9.part1 and t9.idxname = t8.idxname
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and t7.tabid = t5.ptabid""", table.name.lower())
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def fkey_rec():
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return {
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'name' : None,
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'constrained_columns' : [],
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'referred_schema' : None,
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'referred_table' : None,
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'referred_columns' : []
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}
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fkeys = util.defaultdict(fkey_rec)
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for cons_name, cons_type, local_column, remote_table, remote_column in rows:
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rec = fkeys[cons_name]
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rec['name'] = cons_name
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local_cols, remote_cols = rec['constrained_columns'], rec['referred_columns']
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if not rec['referred_table']:
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rec['referred_table'] = remote_table
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local_cols.append(local_column)
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remote_cols.append(remote_column)
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return fkeys.values()
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@reflection.cache
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def get_primary_keys(self, connection, table_name, schema=None, **kw):
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c = connection.execute("""select t4.colname as local_column
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from sysconstraints as t1 , systables as t2 ,
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sysindexes as t3 , syscolumns as t4
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where t1.tabid = t2.tabid and t2.tabname=? and t1.constrtype = 'P'
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and t3.tabid = t2.tabid and t3.idxname = t1.idxname
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and t4.tabid = t2.tabid and t4.colno = t3.part1""", table.name.lower())
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return [r[0] for r in c.fetchall()]
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@reflection.cache
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def get_indexes(self, connection, table_name, schema, **kw):
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# TODO
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return []
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