DBMS interaction cases (ORACLE, POSTGRESQL, SQLACLHEMY)

dbms_interaction.py

# RAW CX_ORACLE

import cx_Oracle
import os

DB_USERNAME = '...'
DB_PASSWORD = '...'
DB_SID = '...' # basicaly a schema
DB_IP = '...'
DB_PORT = int

def get_sql_connection():
    """Returns pre-configured Oracle connection.
    """
    os.environ['NLS_LANG'] = '.UTF8'  # to receive properly encoded data (if not english)

    """
    TNS (Transparent Network Substrate) is Oracle's networking architecture. 
    TNS provides a uniform application interface to enable network
    """
    dsn = cx_Oracle.makedsn(DB_IP,  # dsn => data source name
                            DB_PORT, 
                            DB_SID)  

    conn = cx_Oracle.connect(DB_USERNAME, DB_PASSWORD, dsn)

    return conn
  
  
# RAW PSYCOPG2 

import psycopg2

from psycopg2 import IntegrityError

conn = psycopg2.connect(database='...', 
                        user='...', 
                        password='...', 
                        host='...', 
                        port='...')

c = conn.cursor()
conn.autocommit = True

 
# SQL ALCHEMY

from sqlalchemy import create_engine, MetaData

CS = 'connection string'  # your connection string

conn = create_engine(CS)

meta = MetaData(schema='data', bind=eng)
meta.reflect()

test = meta.tables['data.test']