ems/src/modules/database.py

'''
Created on 26.11.2013

@author: Philipp Rauch
'''
from MySQLdb import connect
from datetime import  date, timedelta
from decimal import Decimal

tables = {}

def get_tables(cur, db):
    sql_tables = 'SHOW TABLES FROM %s'
    tables = []
    cur.execute(sql_tables % db)

    #TODO try - except
    for i in cur:
        tables.append(i[0])
    return tables


def get_prime(cur, tabele):
    sql_get_prim = "SHOW COLUMNS FROM %s WHERE `Key` = 'PRI'"
    sql_get_no_prim = "SHOW COLUMNS FROM %s WHERE `Key` != 'PRI'"
    collum = []
    cur.execute(sql_get_prim % tabele)

    #TODO try - except
    for i in cur:
        collum.append(i[0])

    cur.execute(sql_get_no_prim % tabele)
    for i in cur:
        collum.append(i[0])

    return collum

def setup(conf):
    '''
    establishes a connection to the database and returns a cursor

    @return: cursor to the database
    '''
    connection = connect(host = conf['mySQL_server'],
                        user = conf['mySQL_user'],
                        passwd = conf['mySQL_pass'],
                        db = conf['mySQL_database'],
                        port = int(conf['mySQL_port']))
    cursor = connection.cursor()

    tab = get_tables(cursor, conf['mySQL_database'])
    for i in tab:
        primes = get_prime(cursor, i)
        tables[i] = primes
    print tables

    return cursor

def loop(cursor, item):
    '''


    '''
    sql_values = 'SELECT * FROM %s ORDER BY %s DESC LIMIT 1'

    path = item.split('/')
    if path[0] == '':
        path.remove('')

    table = path[len(path) -1]
    if table == 'device':
        tmp = { table : {} }
        for i in tables.keys():
            tmp[table][i] = {}
        return tmp


    cursor.execute(sql_values % (table, tables[table][0]))
    values = []
    for row in cursor:
        values = row

    result = {}

    for i in range(0, len(tables[table])):
        if values == []:
            result[tables[table][i]] = None
        else:
            if isinstance(values[i], date) or isinstance(values[i], timedelta):
                result[tables[table][i]] = str(values[i])
            elif isinstance(values[i], Decimal):
                result[tables[table][i]] = float(values[i])
            else:
                result[tables[table][i]] = values[i]

#     for p in range(len(path)):
#         result = { path.pop() : result }
    result = {item : result}

    return result

def close(cursor):
    pass