This is class implementation of the portgresql using python.

database_portgres.py

#!/usr/bin/python

import psycopg2

class database(object):
    def __init__(self,database,table):
        self.database = database
        self.table = table
        self.sql_do('create table if not exists '+self.table+' ( key TEXT,data TEXT)')
    def sql_do(self, sql, *params):
        self._db.execute(sql, params)
        self._conn.commit()
    def insert(self, row):
        # if data is string so use '{}' instead of {} , because the portgres wants "hello" not hello
        #print('insert into public.{} (key, data) values ({}, {})'.format(self._table,row['key'], row['data']))
        self._db.execute('insert into public.{} (key, data) values ({}, {})'.format(self._table,row['key'], row['data']))
        self._conn.commit()
    def retrieve(self, key):
        cursor = self._db.execute('select key,data from {} where key = {}'.format(self._table,key))
        return dict(cursor.fetchone())
    def update(self, row):
        self._db.execute('update {} set data={} where key = {}'.format(self._table,row['data'],row['key']))
        self._conn.commit()
    def delete(self, key):
        self._db.execute('delete from {} where key = {}'.format(self._table,key))
        self._conn.commit()




    def __iter__(self):
        self._db.execute('select * from {} '.format(self._table))
        for row in self._db:
            yield row
    @property
    def database(self):
        return self.database
    @database.setter
    def database(self, fn):
        self._database = fn
        self._conn = psycopg2.connect(database = fn, user = "postgres", password = "moazam@123", host = "127.0.0.1", port = "5432")
        self._db =self._conn.cursor()
        print('#'*3 + " connected to database " +fn+' '+'#'*3)
    @database.deleter
    def database(self):
        self.close()
    @property
    def table(self):
        return self._table
    @table.setter
    def table(self, t):
        self._table = t
    def close(self):
        self._db.close()
if __name__ == '__main__':
    d=database(database='sample_db',table='test')
    d.insert({"key": 1,"data": 10})
    for i in d:
        print(i)