import psycopg2
from psycopg2.extras import RealDictCursor


dsn = """host='localhost' port='5432'
         dbname='mydb' user='pg' password='pg'"""
con = psycopg2.connect(dsn, cursor_factory=RealDictCursor)

create_table = '''
    drop table if exists users;
    create table users (
        id serial primary key not null,
        username varchar(255) not null
    );
'''

insert_data = '''
    insert into users (id, username)
    values (%(id)s,%(username)s);
'''


with con.cursor() as cursor:
    cursor.execute(create_table)
    cursor.execute(insert_data, {'id': 1, 'username': 'fred'})
    fred = cursor.execute("select * from users where username == 'fred';")