Display PostgreSQL data as an interactive table in Jupyter Notebook using Python

Retrieve data from PostgreSQL

You will need following packages:

mercury
pandas
psycopg2
dotenv
os

mercury is a package for turning notebooks to web apps.
pandas is for data manipulation.
psycopg2 allows to connect with the database.
dotenv is for storing secrets.
os allows to do basic system operations.

Make sure that you have installed them before start doing anything.

1. Import packages

Firstly, install required packages:

import mercury as mr
import pandas as pd
import psycopg2 as ps
from dotenv import load_dotenv
import os

2. Connect with database

Then, create a function which allows to connect with database:

load_dotenv()
def db_engine():
    host = os.environ.get("DB_HOST")
    port = os.environ.get("DB_POST")
    user = os.environ.get("DB_USERNAME")
    password = os.environ.get("DB_PASSWORD")
    db = os.environ.get("DB_DATABASE")
    
    return f"user='{user}' password='{password}' host='{host}' port='{port}' dbname='{db}'"

To keep credentials safe we use dotenv method.

You can get more information about in our article: 3 ways to access credentials in Jupyter Notebook (opens in a new tab)

After that, connect with your database. Use try block to detect possible errors.

try:
    conn = ps.connect(db_engine())
except Exception as e:
    print(f"problems: {e}")

3. Send queries

Now, you have to create a queries using SQL. Here an example query:

query = "select username, id, email, last_login::date, date_joined::date from auth_user;"

4. Get responses

To get responses update try block:

try:
    conn = ps.connect(db_engine())
    cur = conn.cursor()
    cur.execute(query)
    response = cur.fetchall()
    cur.close()
except Exception as e:
    print(f"problems: {e}")

cur = conn.cursor() creates a cursor that allows your program to move around your database.
cur.execute() sends your query.
cur.fetchall() gets a response for your query.
cur.close() closes a cursor.

Turn data into an interactive table

After you got all of needed information from the database, it's time to display them as an interactive table.

Convert your Data into DataFrame using pandas :

df = pd.DataFrame(response, columns=['Username', 'ID', 'Email', 'Last login', 'Data joined',])

It's important to name all of colums, no more, no less.

Next, use Table Mercury Widget to create an interactive table. Write following code:

mr.Table(data=df, width="auto")

data is a name of DataFrame which you want to show in table.
width sets width of columns in table.

Result

After all, your code should look like this:

And here is the result:

We blured username and email columns for legal reasons.

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Upload files

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Then, choose file which you want to upload and confirm it.

Share your site

After all, it should look like this:

We blured username and email columns for legal reasons.

Now you can share your site with other users!

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