Added support for SA 0.5 (previously only 0.6 was supported).
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Lance Edgar
parent
fd200738b9
commit
617c28e8c7
7 changed files with 221 additions and 135 deletions
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#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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################################################################################
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#
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# SQLBase7-SA -- SQLAlchemy driver/dialect for Centura SQLBase v7
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# Copyright © 2010 Lance Edgar
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#
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# This file is part of SQLBase7-SA.
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#
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# SQLBase7-SA is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# SQLBase7-SA is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with SQLBase7-SA. If not, see <http://www.gnu.org/licenses/>.
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#
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################################################################################
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from sqlalchemy.engine.default import DefaultDialect
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from sqlalchemy import types, and_
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from sqlalchemy.sql.compiler import SQLCompiler
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from sqlalchemy.sql.expression import Join
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class LimitClauseNotSupported(Exception):
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def __init__(self, limit, offset):
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self.limit = limit
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self.offset = offset
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def __str__(self):
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return "Centura SQLBase 7.5.1 doesn't support a LIMIT clause for the SELECT statement (received: limit = %u, offset = %u)" % (self.limit, self.offset)
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class SQLBase7Compiler(SQLCompiler):
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# Most of the code below was copied from the Oracle dialect. Thanks to Michael Bayer
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# for pointing that out. Oh, and for writing SQLAlchemy; that was pretty cool.
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def visit_join(self, join, **kwargs):
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kwargs['asfrom'] = True
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return self.process(join.left, **kwargs) + ", " + self.process(join.right, **kwargs)
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def visit_select(self, select, **kwargs):
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froms = select._get_display_froms()
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whereclause = self._get_join_whereclause(froms)
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if whereclause is not None:
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select = select.where(whereclause)
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if select._limit is not None or select._offset is not None:
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raise LimitClauseNotSupported(select._limit, select._offset)
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kwargs['iswrapper'] = getattr(select, '_is_wrapper', False)
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return SQLCompiler.visit_select(self, select, **kwargs)
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def _get_join_whereclause(self, froms):
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clauses = []
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def visit_join(join):
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clauses.append(join.onclause)
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for j in join.left, join.right:
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if isinstance(j, Join):
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visit_join(j)
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for f in froms:
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if isinstance(f, Join):
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visit_join(f)
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if clauses:
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return and_(*clauses)
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return None
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def visit_ilike_op(self, binary, **kw):
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escape = binary.modifiers.get("escape", None)
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return '@lower(%s) LIKE @lower(%s)' % (
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self.process(binary.left, **kw),
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self.process(binary.right, **kw)) \
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+ (escape and ' ESCAPE \'%s\'' % escape or '')
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class SQLBase7Dialect(DefaultDialect):
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name = 'sqlbase7'
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max_identifier_length = 18
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# # Hmm, it'd be great if these actually did something...
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# supports_unicode_statements = False
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# supports_unicode_binds = False
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statement_compiler = SQLBase7Compiler
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type_map = {
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'CHAR' : types.CHAR,
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'DATE' : types.DATE,
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'DECIMAL' : types.DECIMAL,
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'FLOAT' : types.FLOAT,
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'SMALLINT' : types.SMALLINT,
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'TIME' : types.TIME,
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'TIMESTMP' : types.TIMESTAMP,
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'VARCHAR' : types.VARCHAR,
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}
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def _check_unicode_returns(self, connection):
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return False
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def get_table_names(self, connection, schema=None, **kw):
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if schema is None:
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schema = ''
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else:
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schema = '%s.' % schema
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cursor = connection.connection.cursor()
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table_names = [row.NAME for row in cursor.execute(
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"SELECT NAME FROM %sSYSTABLES WHERE REMARKS IS NOT NULL" % schema
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)]
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cursor.close()
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return table_names
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def get_columns(self, connection, table_name, schema=None, **kw):
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if schema is None:
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schema = ''
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else:
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schema = '%s.' % schema
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cursor = connection.connection.cursor()
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columns = []
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for row in cursor.execute("SELECT NAME,COLTYPE,NULLS FROM %sSYSCOLUMNS WHERE TBNAME = '%s'" % (schema, table_name)):
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columns.append({
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'name' : row.NAME,
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'type' : self.type_map[row.COLTYPE],
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'nullable' : row.NULLS == 'Y',
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'default' : None,
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'autoincrement' : False,
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})
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cursor.close()
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return columns
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def get_primary_keys(self, connection, table_name, schema=None, **kw):
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if schema is None:
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schema = ''
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else:
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schema = '%s.' % schema
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cursor = connection.connection.cursor()
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primary_keys = [row.COLNAME for row in cursor.execute(
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"SELECT COLNAME FROM %sSYSPKCONSTRAINTS WHERE NAME = '%s' ORDER BY PKCOLSEQNUM" % (schema, table_name)
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)]
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cursor.close()
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return primary_keys
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def get_foreign_keys(self, connection, table_name, schema=None, **kw):
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return []
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def get_indexes(self, connection, table_name, schema=None, **kw):
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return []
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def do_execute(self, cursor, statement, parameters, context=None):
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# For some (perhaps good?) reason, the SQLBase ODBC driver doesn't like
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# parameters if they're of Unicode or Long type. I'd hoped at first that
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# the "supports_unicode_binds" attribute would take care of the Unicode
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# problem but it didn't seem to. And now that the Long parameters seem
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# to throw the same error, so...
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_parameters = []
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for parameter in parameters:
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if isinstance(parameter, unicode):
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parameter = str(parameter)
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elif isinstance(parameter, long):
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parameter = int(parameter)
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_parameters.append(parameter)
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parameters = tuple(_parameters)
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cursor.execute(statement, parameters)
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