# Database access

    if hasattr(cur, 'query'): raw_query = cur.query

    elif hasattr(cur, '_last_executed'): raw_query = cur._last_executed

    if raw_query != None: return raw_query

    '''For params, see get_cur_query()'''

    def __init__(self, name, cause=None):

    def __init__(self, value, cause=None):

        DbException.__init__(self, 'for value: '+strings.as_tt(repr(value)),

            cause)

    def __init__(self, type_, name, cause=None):

        DbException.__init__(self, 'for type: '+strings.as_tt(str(type_))

            +'; name: '+strings.as_tt(name), cause)

        self.type = type_

        self.name = name

    def __init__(self, name, cols, cause=None):

            +' constraint on columns: '+strings.as_tt(', '.join(cols)), cause)

    def __init__(self, type_, col, cause=None):

        DbException.__init__(self, 'Missing cast to type '+strings.as_tt(type_)

            +' on column: '+strings.as_tt(col), cause)

        self.type = type_

        self.col = col

class DbWarning(UserWarning): pass

def col_names(cur): return (col[0] for col in cur.description)

def rows(cur): return iter(lambda: cur.fetchone(), None)

def consume_rows(cur):

    '''Used to fetch all rows so result will be cached'''

    iters.consume_iter(rows(cur))

def next_row(cur): return rows(cur).next()

def row(cur):

    row_ = next_row(cur)

    consume_rows(cur)

    return row_

def next_value(cur): return next_row(cur)[0]

def value(cur): return row(cur)[0]

def values(cur): return iters.func_iter(lambda: next_value(cur))

def value_or_none(cur):

    try: return value(cur)

    except StopIteration: return None

    if module == 'psycopg2' or module == None: quote = '"'

    else: raise NotImplementedError("Can't escape name for "+module+' database')

def esc_name_by_engine(engine, name, **kw_args):

    return esc_name_by_module(db_engines[engine][0], name, **kw_args)

def esc_name(db, name, **kw_args):

    return esc_name_by_module(util.root_module(db.db), name, **kw_args)

def qual_name(db, schema, table):

    def esc_name_(name): return esc_name(db, name)

    table = esc_name_(table)

    if schema != None: return esc_name_(schema)+'.'+table

    else: return table

    'MySQL': ('MySQLdb', {'password': 'passwd', 'database': 'db'}),

    'PostgreSQL': ('psycopg2', {}),

}

DatabaseErrors_set = set([DbException])

DatabaseErrors = tuple(DatabaseErrors_set)

def _add_module(module):

    DatabaseErrors_set.add(module.DatabaseError)

    global DatabaseErrors

    DatabaseErrors = tuple(DatabaseErrors_set)

def db_config_str(db_config):

    return db_config['engine']+' database '+db_config['database']

        '''

        @param debug_temp Whether temporary objects should instead be permanent.

            This assists in debugging the internal objects used by the program.

        '''

        self.caching = caching

    def __getattr__(self, name):

        if name == '__dict__': raise Exception('getting __dict__')

        if name == 'db': return self._db()

        else: raise AttributeError()

    def __getstate__(self):

        state = copy.copy(self.__dict__) # shallow copy

        return state

        self.__db = None

        # Do not do this in test mode as it would roll back everything

        if self.autocommit: self.close()

        # Connection will be reopened automatically on first query

        if self.__db == None:

            # Process db_config

            db_config = self.db_config.copy() # don't modify input!

            module = __import__(module_name)

            _add_module(module)

            for orig, new in mappings.iteritems():

                try: util.rename_key(db_config, orig, new)

                except KeyError: pass

            # Connect

            self.__db = module.connect(**db_config)

            self._savepoint += 1

                import psycopg2.extensions

                self.db.set_isolation_level(

                    psycopg2.extensions.ISOLATION_LEVEL_READ_COMMITTED)

                search_path.append(value(run_query(self, 'SHOW search_path',

                    log_level=4)))

                run_query(self, 'SET search_path TO '+(','.join(search_path)),

                    log_level=3)

        return self.__db

                self.result = e # cache the exception as the result

                self._cache_result()

                raise

            # Always cache certain queries

            if query.startswith('CREATE') or query.startswith('ALTER'):

                # so don't cache ADD COLUMN unless it has distinguishing comment

                if query.find('ADD COLUMN') < 0 or query.endswith('*/'):

            row = self.inner.fetchone()

            # otherwise, fetched all rows

            return row

        def _cache_result(self):

            # inserts are not idempotent. Other non-SELECT queries don't have

            # their result set read, so only exceptions will be cached (an

            # invalid query will always be invalid).

                    util.dict_subset(dicts.AttrsDictView(self),

                    ['query', 'result', 'rowcount', 'description']))

            def __init__(self, cached_result): self.__dict__ = cached_result

                # otherwise, result is a rows list

                self.iter = iter(self.result)

            def fetchone(self):

                try: return self.iter.next()

                except StopIteration: return None

        except NotImplementedError, e:

            module = util.root_module(self.db)

            if module == 'MySQLdb':

                import _mysql

                str_ = _mysql.escape_string(value)

            else: raise e

        '''Standardizes SQL code.

        * Ensures that string literals are prefixed by `E`

        '''

        if str_.startswith("'"): str_ = 'E'+str_

        return str_

        if self.can_mogrify(): return self.db.cursor().mogrify(query, params)

        else: raise NotImplementedError("Can't mogrify query")

            for msg in self.db.notices:

                if msg not in self._notices_seen:

                    self._notices_seen.add(msg)

                    self.log_debug(msg, level=2)

            throws one of these exceptions.

            this instead of being output. This allows you to filter log messages

            depending on the result of the query.

        def log_msg(query):

            if used_cache: cache_status = 'cache hit'

            elif cacheable: cache_status = 'cache miss'

            else: cache_status = 'non-cacheable'

            return 'DB query: '+cache_status+':\n'+strings.as_code(query, 'SQL')

            if cacheable:

                try:

                except KeyError: cur = self.DbCursor(self)

            else: cur = self.db.cursor()

            if self.debug and debug_msg_ref == None: # log before running

                self.log_debug(log_msg(query), log_level)

                cur.execute(query)

                self.do_autocommit()

            except Exception, e:

                _add_cursor_info(e, self, query)

                raise

        return cur

        prev_isolation_level = self.db.isolation_level

            psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)

        self._savepoint += 1

        else: query = 'SAVEPOINT '+savepoint

        self.run_query(query, log_level=4)

        try:

            return func()

            if top: self.run_query('COMMIT', log_level=4)

            else: query = 'ROLLBACK TO SAVEPOINT '+savepoint

            self.run_query(query, log_level=4)

            # Always release savepoint, because after ROLLBACK TO SAVEPOINT,

            # "The savepoint remains valid and can be rolled back to again"

            # (http://www.postgresql.org/docs/8.3/static/sql-rollback-to.html).

                self.run_query('RELEASE SAVEPOINT '+savepoint, log_level=4)

            self._savepoint -= 1

            assert self._savepoint >= 0

            self.do_autocommit() # OK to do this after ROLLBACK TO SAVEPOINT

    def do_autocommit(self):

        '''Autocommits if outside savepoint'''

        if self.autocommit and self._savepoint == 1:

            'USER-DEFINED'), sql_gen.Col('udt_name'))

            sql_gen.Cast('boolean', sql_gen.Col('is_nullable'))]

        conds = [('table_name', col.table.name), ('column_name', col.name)]

        schema = col.table.schema

        if schema != None: conds.append(('table_schema', schema))

        return sql_gen.TypedCol(col.name, type_, default, nullable)

    def TempFunction(self, name):

        if self.debug_temp: schema = None

        else: schema = 'pg_temp'

        return sql_gen.Function(name, schema)

    log_ignore_excs=None, **kw_args):

    log_ignore_excs = tuple(log_ignore_excs)

    # But if filtering with log_ignore_excs, wait until after exception parsing

            else: return run() # don't need savepoint if cached

        except Exception, e:

                constraint, table = match.groups()

                if recover: # need auto-rollback to run index_cols()

                    try: cols = index_cols(db, table, constraint)

                    except NotImplementedError: pass

                raise DuplicateKeyException(constraint, cols, e)

            if match: raise NullValueException('NOT NULL', [match.group(1)], e)

                raise InvalidValueException(strings.to_unicode(value), e)

            if match:

                col, type_ = match.groups()

                raise MissingCastException(type_, col, e)

                type_, name = match.groups()

                raise DuplicateException(type_, name, e)

            raise # no specific exception raised

    except log_ignore_excs:

        log_level += 2

        raise

    finally:

            db.log_debug(debug_msg_ref[0], log_level)

        version = int(version)+1

    table = sql_gen.as_Table(table)

    run_query(db, 'LOCK TABLE '+table.to_str(db)+' IN '+mode+' MODE')

    For params, see run_query().

    '''

    assert isinstance(into, sql_gen.Table)

    into.schema = None

    # Create table

    while True:

        create_query = 'CREATE'

        if temp: create_query += ' TEMP'

        create_query += ' TABLE '+into.to_str(db)+' AS\n'+query

            cur = run_query(db, create_query, **kw_args)

                # CREATE TABLE AS sets rowcount to # rows in query

            break

            # try again with next version of name

    if add_indexes_: add_indexes(db, into)

    # According to the PostgreSQL doc, "The autovacuum daemon cannot access and

    # therefore cannot vacuum or analyze temporary tables. [...] if a temporary

    # table is going to be used in complex queries, it is wise to run ANALYZE on

    # the temporary table after it is populated."

    # (http://www.postgresql.org/docs/9.1/static/sql-createtable.html)

    # If into is not a temp table, ANALYZE is useful but not required.

    return cur

        * compare_right_side: sql_gen.ValueCond|literal value

        use all columns

    assert start == None or isinstance(start, (int, long))

        if distinct_on != []: order_by = None

        else: order_by = pkey(db, table0, recover=True)