tryton/trytond/backend/database.py

#This file is part of Tryton.  The COPYRIGHT file at the top level of
#this repository contains the full copyright notices and license terms.
from trytond.const import MODEL_CACHE_SIZE

DatabaseIntegrityError = None
DatabaseOperationalError = None


class DatabaseInterface(object):
    '''
    Define generic interface for database connection
    '''
    flavor = None

    def __new__(cls, database_name=''):
        return object.__new__(cls)

    def __init__(self, database_name=''):
        self.database_name = database_name

    def connect(self):
        '''
        Connect to the database

        :return: the database
        '''
        raise NotImplementedError

    def cursor(self, autocommit=False, readonly=False):
        '''
        Retreive a cursor on the database

        :param autocommit: a boolean to active autocommit
        :return: a Cursor
        '''
        raise NotImplementedError

    def close(self):
        '''
        Close all connection
        '''
        raise NotImplementedError

    @staticmethod
    def create(cursor, database_name):
        '''
        Create a database

        :param database_name: the database name
        '''
        raise NotImplementedError

    @staticmethod
    def drop(cursor, database_name):
        '''
        Drop a database

        :param cursor: a cursor on an other database
        :param database_name: the database name
        '''
        raise NotImplementedError

    @staticmethod
    def dump(database_name):
        '''
        Dump a database

        :param database_name: the database name
        :return: the dump
        '''
        raise NotImplementedError

    @staticmethod
    def restore(database_name, data):
        '''
        Restore a database

        :param database_name: the database name
        :param data: the data
        :return: True if succeed
        '''
        raise NotImplementedError

    @staticmethod
    def list(cursor):
        '''
        Get the list of database

        :return: a list of database name
        '''
        raise NotImplementedError

    @staticmethod
    def init(cursor):
        '''
        Initialize a database

        :param cursor: a cursor on the database
        '''
        raise NotImplementedError


class CursorInterface(object):
    '''
    Define generic interface for database cursor
    '''
    IN_MAX = 1000

    def __init__(self):
        self.cache = {}

    def get_cache(self, context=None):
        '''
        Return cache for the context

        :param context: the context
        :return: the cache dictionary
        '''
        from trytond.cache import LRUDict
        from trytond.transaction import Transaction
        user = Transaction().user
        if context is None:
            context = {}
        cache_ctx = context.copy()
        for i in ('_timestamp', '_delete', '_create_records',
                '_delete_records'):
            if i in cache_ctx:
                del cache_ctx[i]
        return self.cache.setdefault((user, repr(cache_ctx)),
            LRUDict(MODEL_CACHE_SIZE))

    def execute(self, sql, params=None):
        '''
        Execute a query

        :param sql: a sql query string
        :param params: a tuple or list of parameters
        '''
        raise NotImplementedError

    def close(self, close=False):
        '''
        Close the cursor

        :param close: boolean to not release cursor in pool
        '''
        raise NotImplementedError

    def commit(self):
        '''
        Commit the cursor
        '''
        for cache in self.cache.itervalues():
            cache.clear()

    def rollback(self):
        '''
        Rollback the cursor
        '''
        for cache in self.cache.itervalues():
            cache.clear()

    def test(self):
        '''
        Test if it is a Tryton database.
        '''
        raise NotImplementedError

    def nextid(self, table):
        '''
        Return the next sequenced id for a table.

        :param table: the table name
        :return: an integer
        '''

    def setnextid(self, table, value):
        '''
        Set the current sequenced id for a table.

        :param table: the table name
        '''

    def currid(self, table):
        '''
        Return the current sequenced id for a table.

        :param table: the table name
        :return: an integer
        '''

    def lastid(self):
        '''
        Return the last id inserted.

        :return: an integer
        '''

    def lock(self, table):
        '''
        Lock the table

        :param table: the table name
        '''
        raise NotImplementedError

    def has_constraint(self):
        '''
        Return True if database handle constraint.

        :return: a boolean
        '''
        raise NotImplementedError

    def update_auto_increment(self, table, value):
        '''
        Update auto_increment value of table

        :param table: the table name
        :param value: the auto_increment value
        '''
        pass

    def has_returning(self):
        '''
        Return True if database implements RETURNING clause in INSERT or UPDATE
        statements.

        :return: a boolean
        '''