Python db.DBError方法代碼示例

# 需要導入模塊: from bsddb import db [as 別名]
# 或者: from bsddb.db import DBError [as 別名]
def CreateTable(self, table, columns):
        """CreateTable(table, columns) - Create a new table in the database.

        raises TableDBError if it already exists or for other DB errors.
        """
        assert isinstance(columns, list)

        txn = None
        try:
            # checking sanity of the table and column names here on
            # table creation will prevent problems elsewhere.
            if contains_metastrings(table):
                raise ValueError(
                    "bad table name: contains reserved metastrings")
            for column in columns :
                if contains_metastrings(column):
                    raise ValueError(
                        "bad column name: contains reserved metastrings")

            columnlist_key = _columns_key(table)
            if getattr(self.db, "has_key")(columnlist_key):
                raise TableAlreadyExists, "table already exists"

            txn = self.env.txn_begin()
            # store the table's column info
            getattr(self.db, "put_bytes", self.db.put)(columnlist_key,
                    pickle.dumps(columns, 1), txn=txn)

            # add the table name to the tablelist
            tablelist = pickle.loads(getattr(self.db, "get_bytes",
                self.db.get) (_table_names_key, txn=txn, flags=db.DB_RMW))
            tablelist.append(table)
            # delete 1st, in case we opened with DB_DUP
            self.db.delete(_table_names_key, txn=txn)
            getattr(self.db, "put_bytes", self.db.put)(_table_names_key,
                    pickle.dumps(tablelist, 1), txn=txn)

            txn.commit()
            txn = None
        except db.DBError, dberror:
            if txn:
                txn.abort()
            if sys.version_info < (2, 6) :
                raise TableDBError, dberror[1]
            else :
                raise TableDBError, dberror.args[1] 

# 需要導入模塊: from bsddb import db [as 別名]
# 或者: from bsddb.db import DBError [as 別名]
def CreateOrExtendTable(self, table, columns):
        """CreateOrExtendTable(table, columns)

        Create a new table in the database.

        If a table of this name already exists, extend it to have any
        additional columns present in the given list as well as
        all of its current columns.
        """
        assert isinstance(columns, list)

        try:
            self.CreateTable(table, columns)
        except TableAlreadyExists:
            # the table already existed, add any new columns
            txn = None
            try:
                columnlist_key = _columns_key(table)
                txn = self.env.txn_begin()

                # load the current column list
                oldcolumnlist = pickle.loads(
                    getattr(self.db, "get_bytes",
                        self.db.get)(columnlist_key, txn=txn, flags=db.DB_RMW))
                # create a hash table for fast lookups of column names in the
                # loop below
                oldcolumnhash = {}
                for c in oldcolumnlist:
                    oldcolumnhash[c] = c

                # create a new column list containing both the old and new
                # column names
                newcolumnlist = copy.copy(oldcolumnlist)
                for c in columns:
                    if not c in oldcolumnhash:
                        newcolumnlist.append(c)

                # store the table's new extended column list
                if newcolumnlist != oldcolumnlist :
                    # delete the old one first since we opened with DB_DUP
                    self.db.delete(columnlist_key, txn=txn)
                    getattr(self.db, "put_bytes", self.db.put)(columnlist_key,
                                pickle.dumps(newcolumnlist, 1),
                                txn=txn)

                txn.commit()
                txn = None

                self.__load_column_info(table)
            except db.DBError, dberror:
                if txn:
                    txn.abort()
                if sys.version_info < (2, 6) :
                    raise TableDBError, dberror[1]
                else :
                    raise TableDBError, dberror.args[1] 

# 需要導入模塊: from bsddb import db [as 別名]
# 或者: from bsddb.db import DBError [as 別名]
def Insert(self, table, rowdict) :
        """Insert(table, datadict) - Insert a new row into the table
        using the keys+values from rowdict as the column values.
        """

        txn = None
        try:
            if not getattr(self.db, "has_key")(_columns_key(table)):
                raise TableDBError, "unknown table"

            # check the validity of each column name
            if not table in self.__tablecolumns:
                self.__load_column_info(table)
            for column in rowdict.keys() :
                if not self.__tablecolumns[table].count(column):
                    raise TableDBError, "unknown column: %r" % (column,)

            # get a unique row identifier for this row
            txn = self.env.txn_begin()
            rowid = self.__new_rowid(table, txn=txn)

            # insert the row values into the table database
            for column, dataitem in rowdict.items():
                # store the value
                self.db.put(_data_key(table, column, rowid), dataitem, txn=txn)

            txn.commit()
            txn = None

        except db.DBError, dberror:
            # WIBNI we could just abort the txn and re-raise the exception?
            # But no, because TableDBError is not related to DBError via
            # inheritance, so it would be backwards incompatible.  Do the next
            # best thing.
            info = sys.exc_info()
            if txn:
                txn.abort()
                self.db.delete(_rowid_key(table, rowid))
            if sys.version_info < (2, 6) :
                raise TableDBError, dberror[1], info[2]
            else :
                raise TableDBError, dberror.args[1], info[2] 

# 需要導入模塊: from bsddb import db [as 別名]
# 或者: from bsddb.db import DBError [as 別名]
def Modify(self, table, conditions={}, mappings={}):
        """Modify(table, conditions={}, mappings={}) - Modify items in rows matching 'conditions' using mapping functions in 'mappings'

        * table - the table name
        * conditions - a dictionary keyed on column names containing
          a condition callable expecting the data string as an
          argument and returning a boolean.
        * mappings - a dictionary keyed on column names containing a
          condition callable expecting the data string as an argument and
          returning the new string for that column.
        """

        try:
            matching_rowids = self.__Select(table, [], conditions)

            # modify only requested columns
            columns = mappings.keys()
            for rowid in matching_rowids.keys():
                txn = None
                try:
                    for column in columns:
                        txn = self.env.txn_begin()
                        # modify the requested column
                        try:
                            dataitem = self.db.get(
                                _data_key(table, column, rowid),
                                txn=txn)
                            self.db.delete(
                                _data_key(table, column, rowid),
                                txn=txn)
                        except db.DBNotFoundError:
                             # XXXXXXX row key somehow didn't exist, assume no
                             # error
                            dataitem = None
                        dataitem = mappings[column](dataitem)
                        if dataitem is not None:
                            self.db.put(
                                _data_key(table, column, rowid),
                                dataitem, txn=txn)
                        txn.commit()
                        txn = None

                # catch all exceptions here since we call unknown callables
                except:
                    if txn:
                        txn.abort()
                    raise

        except db.DBError, dberror:
            if sys.version_info < (2, 6) :
                raise TableDBError, dberror[1]
            else :
                raise TableDBError, dberror.args[1] 

# 需要導入模塊: from bsddb import db [as 別名]
# 或者: from bsddb.db import DBError [as 別名]
def Delete(self, table, conditions={}):
        """Delete(table, conditions) - Delete items matching the given
        conditions from the table.

        * conditions - a dictionary keyed on column names containing
          condition functions expecting the data string as an
          argument and returning a boolean.
        """

        try:
            matching_rowids = self.__Select(table, [], conditions)

            # delete row data from all columns
            columns = self.__tablecolumns[table]
            for rowid in matching_rowids.keys():
                txn = None
                try:
                    txn = self.env.txn_begin()
                    for column in columns:
                        # delete the data key
                        try:
                            self.db.delete(_data_key(table, column, rowid),
                                           txn=txn)
                        except db.DBNotFoundError:
                            # XXXXXXX column may not exist, assume no error
                            pass

                    try:
                        self.db.delete(_rowid_key(table, rowid), txn=txn)
                    except db.DBNotFoundError:
                        # XXXXXXX row key somehow didn't exist, assume no error
                        pass
                    txn.commit()
                    txn = None
                except db.DBError, dberror:
                    if txn:
                        txn.abort()
                    raise
        except db.DBError, dberror:
            if sys.version_info < (2, 6) :
                raise TableDBError, dberror[1]
            else :
                raise TableDBError, dberror.args[1] 

# 需要導入模塊: from bsddb import db [as 別名]
# 或者: from bsddb.db import DBError [as 別名]
def Drop(self, table):
        """Remove an entire table from the database"""
        txn = None
        try:
            txn = self.env.txn_begin()

            # delete the column list
            self.db.delete(_columns_key(table), txn=txn)

            cur = self.db.cursor(txn)

            # delete all keys containing this tables column and row info
            table_key = _search_all_data_key(table)
            while 1:
                try:
                    key, data = cur.set_range(table_key)
                except db.DBNotFoundError:
                    break
                # only delete items in this table
                if key[:len(table_key)] != table_key:
                    break
                cur.delete()

            # delete all rowids used by this table
            table_key = _search_rowid_key(table)
            while 1:
                try:
                    key, data = cur.set_range(table_key)
                except db.DBNotFoundError:
                    break
                # only delete items in this table
                if key[:len(table_key)] != table_key:
                    break
                cur.delete()

            cur.close()

            # delete the tablename from the table name list
            tablelist = pickle.loads(
                getattr(self.db, "get_bytes", self.db.get)(_table_names_key,
                    txn=txn, flags=db.DB_RMW))
            try:
                tablelist.remove(table)
            except ValueError:
                # hmm, it wasn't there, oh well, that's what we want.
                pass
            # delete 1st, incase we opened with DB_DUP
            self.db.delete(_table_names_key, txn=txn)
            getattr(self.db, "put_bytes", self.db.put)(_table_names_key,
                    pickle.dumps(tablelist, 1), txn=txn)

            txn.commit()
            txn = None

            if table in self.__tablecolumns:
                del self.__tablecolumns[table]

        except db.DBError, dberror:
            if txn:
                txn.abort()
            raise TableDBError(dberror.args[1])