---
title: 'PostgreSQL Python: Update Data in a Table'
page_title: 'PostgreSQL Python: Update Data in a Table'
page_description: 'In this tutorial, you will learn how to update data in a PostgreSQL database table in a Python program using psycopg2 package.'
prev_url: 'https://www.postgresqltutorial.com/postgresql-python/update/'
ogImage: '/postgresqltutorial/vendors_table.png'
updatedOn: '2024-05-19T08:31:04+00:00'
enableTableOfContents: true
previousLink:
  title: 'PostgreSQL Python: Insert Data Into a Table'
  slug: 'postgresql-python/insert'
nextLink:
  title: 'PostgreSQL Python: Querying Data'
  slug: 'postgresql-python/query'
---

**Summary**: in this tutorial, you will learn how to update data in a PostgreSQL table from a Python program.

This tutorial picks up from where the [Inserting Data Into Table Tutorial](insert) left off.

## Steps for updating data in a PostgreSQL table from Python

To update data from a table in Python, you follow these steps:

- First, [connect to the PostgreSQL server](connect).
- Next, create a `cursor` object from the `connection` object.
- Then, execute an [UPDATE](../postgresql-tutorial/postgresql-update) statement by calling the `execute()` method of the `cursor` object.
- After that, commit the changes by calling the `commit()` method of the `connection` object.
- Finally, optionally obtain the number of updated rows from the `rowcount` property of the `cursor` object.

## Updating data in a table example

We will use the `vendors` table in the `suppliers` database for the demonstration:

![vendors_table](/postgresqltutorial/vendors_table.png)

### 1\) Creating update.py module

Suppose a vendor changed its name, you need to reflect these changes in the `vendors` table.

To achieve this, you can define a function `update_vendor()`, which updates the vendor name based on the vendor id.

First, create a new module called `update.py` in the project directory.

Second, define `update_vendor()` function in the `update.py` module:

```python
import psycopg2
from config import load_config


def update_vendor(vendor_id, vendor_name):
    """ Update vendor name based on the vendor id """

    updated_row_count = 0

    sql = """ UPDATE vendors
                SET vendor_name = %s
                WHERE vendor_id = %s"""

    config = load_config()

    try:
        with  psycopg2.connect(**config) as conn:
            with  conn.cursor() as cur:

                # execute the UPDATE statement
                cur.execute(sql, (vendor_name, vendor_id))
                updated_row_count = cur.rowcount

            # commit the changes to the database
            conn.commit()
    except (Exception, psycopg2.DatabaseError) as error:
        print(error)
    finally:
        return updated_row_count

if __name__ == '__main__':
    update_vendor(1, "3M Corp")
```

### 2\) Execute the update.py module

First, open the Command Prompt on Windows or Terminal on Unix\-like systems.

Second, execute the `update.py` module:

```css
python update.py
```

### 3\) Verify the update

First, connect to the PostgreSQL server using the `psql` client tool:

```bash
psql -U postgres
```

Second, change the current database to `suppliers`:

```
\c suppliers
```

Third, retrieve data from the `vendors` table with the vendor id 1:

```
SELECT
  *
FROM
  vendors
WHERE
  vendor_id = 1;
```

Output:

```shell
 vendor_id | vendor_name
-----------+-------------
         1 | 3M Corp
(1 row)
```

The name of the vendor id 1 has been changed as expected.

[Download the project source code](/postgresqltutorial/update.zip)

## Summary

- Use the `execute()` method of a `cursor` object to execute an `UPDATE` statement that updates data in a table