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https://github.com/TimonW-Dev/micropg_lite

Lightweight PostgreSQL database driver for MicroPython (made for ESP8266). Based on micropg by nakagami.
https://github.com/TimonW-Dev/micropg_lite

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Lightweight PostgreSQL database driver for MicroPython (made for ESP8266). Based on micropg by nakagami.

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README

        

# micropg_lite (The worlds lightest PostgreSQL driver for micropython)

A MicroPython PostgreSQL database driver made for microcontrollers (specifically for ESP8266) that are low on RAM.

## Difference between [micropg_lite](https://github.com/TimonW-Dev/micropg_lite) and [micropg](https://github.com/nakagami/micropg)

[micropg_lite](https://github.com/TimonW-Dev/micropg_lite) is a lightweight version based on [micropg](https://github.com/nakagami/micropg) by [
nakagami](https://github.com/nakagami). If you have RAM/memory issues with [micropg](https://github.com/nakagami/micropg) than this library might solve this issue.

The [micropg_lite](https://github.com/TimonW-Dev/micropg_lite) library has some limitations in functionality due to the lightweight.

**For more information, see** [micropg_lite-sql-handling-and-restrictions](#micropg_lite-sql-handling-and-restrictions)

## Installation

1. Download the `micropg_lite.py` file from this repository to your local computer.

2. Copy the `micropg_lite.py` file to the "/lib" folder on the microcontroller using the Thonny IDE or another program. If there is no "lib" folder in the root directory, you have to create it.

**Hint** for the Thony IDE:

Open in the top bar the "View" menu and make sure that the entry "Files" has a "✓", if not then click on "Files". Now you can directly download and upload files from your computer to the microcontroller. You also can create folders on the microcontroller.

3. Now you should be able to import the library to your microcontroller in a MicroPython file.

````python
import micropg_lite
````

If there are problems or questions, open an issue on this github repository.

## microcontroller file tree
````
/
├─ example.py
└─ lib/
└─ micropg_lite.py
````

## Examples
You need to establish a network connection before executing micropg_lite code. The [SELECT example](#select-example-with-wifi-connection) inclueds the wifi template. All other examples do not include the wifi template.

### examples/ folder
The examples/ folder includes the database sql script which was used to create the database and the used data in all those examples. The examples folder also includes the full scripts used in this readme including the wifi connection template.

### SELECT example with wifi connection:
````python
import network # Handles the wifi connection
import micropg_lite

### To Do: Fill in your wifi connection data and change the server data
ssid = 'wifissid' # replace the string with your wifi ssid
password = 'secret' # replase tge string with your wifi password

# Connect to network
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect(ssid, password)

print("Wifi connected")

conn = micropg_lite.connect(host='127.0.0.1', # replace the string with your server ip-address
user='postgres', # replace the string with your user
password='123456', # replace the string with your password
database='exampledatabase')
cur = conn.cursor()

cur.execute('select * from customers')
selectresult = cur.fetchall()
conn.close()

# EXAMPLE: Print raw data
print(selectresult)

# EXAMPLE: Print data table
for r1 in selectresult:
for r2 in r1:
print(r2, end="\t")
print()
````

### INSERT example
````python
conn = micropg_lite.connect(host='127.0.0.1', # replace the string with your server ip-address
user='postgres', # replace the string with your user
password='123456', # replace the string with your password
database='exampledatabase')
cur = conn.cursor()

cur.execute('INSERT INTO customers (id, firstName, lastName, email) values (%s, %s, %s, %s)', ['5', 'David', 'Wilson', '[email protected]'])
conn.close()

````

### UPDATE example
```` python
conn = micropg_lite.connect(host='127.0.0.1', # replace the string with your server ip-address
user='postgres', # replace the string with your user
password='123456', # replace the string with your password
database='exampledatabase')
cur = conn.cursor()

cur.execute('update customers set firstName=\'UpdatedFirstName\' where id=2;')
conn.close()
````

### DELETE example
```` python
conn = micropg_lite.connect(host='127.0.0.1', # replace the string with your server ip-address
user='postgres', # replace the string with your user
password='123456', # replace the string with your password
database='exampledatabase')
cur = conn.cursor()

cur.execute('delete from customers where id=1;')
conn.close()

````

## micropg_lite sql handling and restrictions
- You have to put IDs into ' '. For example, see the IDs in the `
[insert example](#insert-example)
- Escape parameters are not always working. You may have to change your queries. For example, take a look at the sql query used in the [update example](#update-example)
- You can only commit. Rollback is in [micropg_lite](https://github.com/TimonW-Dev/micropg_lite) not supported
- You can only execute INSERT, SELECT, UPDATE and DELETE statements
- You cannot execute "CREATE DATABASE" or "DROP DATABASE" queries
- Not support for array data types.
- Not support for prepared statements.