# Connecting with Python
This guide explains how to establish a connection between a **Python** application and a **PostgreSQL** database using the **`psycopg2-binary`** package. It walks through the necessary setup, configuration, and execution of a simple SQL query.
### **Variables**
To connect to a PostgreSQL database, you only need one environment variable — the **connection URI**. This URI contains all the necessary information like username, password, host, port, and database name.
Variable
Description
Purpose
**POSTGRESQL\_URI**
Full PostgreSQL connection string (from the Elestio service overview page)
Provides all necessary credentials and endpoint details in a single URI format.
The URI will look like this:
```bash
postgresql://:@:/
```
You can find the details needed in the URI from the **Elestio service overview** details. Copy and replace the variables carefully in the URI example provided above.
### **Prerequisites**
##### **Install Python**
Check if Python is installed by running:
```bash
python --version
```
If not installed, download it from [python.org](https://www.python.org/) and install it.
##### **Install `psycopg2-binary` Package**
The `psycopg2-binary` package enables Python applications to interact with PostgreSQL. Install it using:
```bash
pip install psycopg2-binary
```
### **Code**
Once all prerequisites are set up, create a new file named `pg.py` and add the following code and replace the `POSTGRESQL_URI` with actual link or in environment setup as you wish:
```python
import psycopg2
def get_db_version():
try:
db_connection = psycopg2.connect('POSTGRESQL_URI')
db_cursor = db_connection.cursor()
db_cursor.execute('SELECT VERSION()')
db_version = db_cursor.fetchone()[0]
return db_version
except Exception as e:
print(f"Database connection error: {e}")
return None
finally:
if 'db_cursor' in locals():
db_cursor.close()
if 'db_connection' in locals():
db_connection.close()
def display_version():
version = get_db_version()
if version:
print(f"Connected to PostgreSQL: {version}")
if __name__ == "__main__":
display_version()
```
To execute the script, open the terminal or command prompt and navigate to the directory where `pg.py`. Once in the correct directory, run the script with the command
```bash
python pg.py
```
If the connection is successful, the terminal will display output similar to:
```
Connected to PostgreSQL: PostgreSQL 16.8 (Debian 16.8-1.pgdg120+1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 12.2.0-14) 12.2.0, 64-bit
```