dbms database class

nerdcoder (Dan Larsen) — Tue, 03 Jul 2007 21:46:51 GMT

I'm at my first attempt at creating something for the PyS60 and I needed a simple sql wrapper class...
I'm an experienced programmer, but has never programmed in python for s60 and it's been a while since I've used Python... So I hope this will help somebody, not annoy ;-)



# Filename: db.py save in your Python dir

import e32db



class db:

    def __init__(self, dbpath):

	self.db = e32db.Dbms()

	self.dbv = e32db.Db_view()

	self.reset_counters()

	try:

	    self.db.open(unicode(dbpath))

	except:

	    self.db.create(unicode(dbpath))

	    self.db.open(unicode(dbpath))



    def reset_counters(self):

	self.affected_rows = 0

	self.num_rows = 0

	self.__internal_counter = 0



    def query(self, sql):

	self.reset_counters()

	if sql.lower().startswith('select'):

	    self.dbv.prepare(self.db, unicode(sql))

	    self.dbv.first_line()

	    self.num_rows = self.dbv.count_line()

	else:

	    self.affected_rows = self.db.execute(unicode(sql))



    def next(self):

	row = {'id': 0}

	if self.num_rows < 1:

	    self.reset_counters()

	    raise StopIteration

	elif self.__internal_counter < self.num_rows:

	    self.dbv.get_line()

	    for i in range(self.dbv.col_count()):

		row[i] = self.dbv.col(i+1)

	    self.dbv.next_line()

	    self.__internal_counter += 1

	    return row

	else:

	    self.reset_counters()

	    raise StopIteration



    def __iter__(self):

	return self

Now to create and fill db, create a file in the same dir as the db.py with this content:



# Change __exec_path to the path of your python script dir

__exec_path = "E:\\Python\\"

dbname = "test"



import sys

sys.path.append(__exec_path)

from db import db



# This will open E:\\Python\test.db - it will be created first, if not existing

mydb = db(__exec_path+dbname+'.db')

mydb.query("create table testing (id counter, name varchar)")

mydb.query("insert into testing (name) values ('test 1')")

mydb.query("insert into testing (name) values ('test 2')")

Now go ahead and have fun:



# Again change __exec_path to the path of your python script dir

__exec_path = "E:\\Python\\"

dbname = "test"



import sys

sys.path.append(__exec_path)

from db import db



# Opens E:\\Python\test.db

mydb = db(__exec_path+dbname+'.db')

mydb.query("select * from testing")

for row in mydb:

    print "-> ",row[0]," ",row[1]," <-"

Have fun!
Dan

DZone Snippets: sql code

dbms database class