brainDB

About:

• This project is based on the btree module from MicroPython which is based on BerkelyDB library.
• Btrees are efficient in retrieving values from given keys. Both keys and values are stored in bytes objects.
• Python datatypes like: int, float, str, list, tuple, set, dict, bytes, bytearray, bool can be used both as keys and values for the database.
• brainDB is compatible with both cpython and micropython
• Because of this compatibility, it is possible to create the database in native system python for later use in micropython versions of micro-controllers.

Easy of use:

db = DB("databaseName")
db.write(key, value)
db.read(key) OR db.read(value=value)

Possible use cases:

• Data Logging from sensors.
• Storing Wifi credentials in ESP8266 / ESP32 boards.
• Can be used to store datasets efficiently for training Machine Learning models as well as storing weights, biases etc for using it in future predictions.
• Everywhere when data needs to be stored and accessed by key

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class brainDB / ubrainDB:

Use	Function
Create a new database by giving it a name The database file is created inside "DB" folder if it doesn't exist. The path can be changed in "ubrainDB.py"	db = DB("someName") db2 = DB("anotherName")
Get the names of all the databases in a list	db.databases()
Set verbose (default is set to 0) If set to 1, it displays information while writing / removing in the database	db.verbose(1)
Write key - value pairs to the current database. The first argument is key and second is value	db.write({777}, 0.12) db.write([1, 1, 0], 1) db.write(0, "zero") db.write("abc", "xyz") db.write([0.1, 0.6, 0.8], 1)
Read value by given key or read key/s by given value	db.read("abc") db.read(value="xyz") db.read([0.1, 0.6, 0.8]) db.read(value=1)
Remove key - value pairs by giving key or value	db.remove({777}) db.remove(value=0.12)
Get sorted keys (Optionally from specified key) Also reverse can be set to True to get the list in reverse order	db.keys() db.keys("abc") db.keys("abc", reverse=True)
Get sorted values (Optionally from specified key) Also reverse can be set to True to get the list in reverse order	db.values() db.values([1, 1, 0]) db.values([1, 1, 0], reverse=True)
Get a dictionary with key - value pairs as bytes objects (Optionally from specified key)	db.items()
Remove a database by it's name. If the current database is selected, it will be erased of all items.	db.remove_database("someName")
Close the current database Read / Write methods will not work after invoking this function	db.close()
It reopens a database after it was closed Read / Write methods will work again	db.reopen()

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Compatibility with CPython

• As I started working on brainDB, it was written only for micropython. But with the help of subprocess module, I made a wrapper around MicroPython to use the script in CPython.
• When brainDB is called in cpython, it is envoking ubrainDB from micropython version of unix to read / write to our database. Basically brainDB uses subprocess module to communicate with ubrainDB

Requirements for CPython (UNIX)

Run install.sh

git clone https://github.com/schikani/brainDB.git
cd brainDB && ./install.sh

Importing the right module

• Notice the difference in importing the right module for micropython as ubrainDB and for cpython as brainDB in the example below.
• All the functions are similar both in brainDB and ubrainDB

CPython

from db_scripts import brainDB as DB
db1 = DB("database1")
db1.write(1, 89) # key, value to write

MicroPython

from db_scripts import ubrainDB as DB
db2 = DB("database2")
db2.write(0, 55)

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Examples:

• Storing 2D / multi-dimensional Arrays

from db_scripts import brainDB as DB

database1 = DB("myDB")
database1.verbose(1)

features = [
    [1, 0, 1, 1, 1, 0, 0],
    [1, 0, 1, 0, 1, 1, 0],
    [0, 0, 1, 0, 0, 0, 0]]

labels = [1, 1, 0]

for f, l in zip(features, labels):
    database1.write(f, l)

features_with_label_one = database1.read(value=1)
print(features_with_label_one)
database1.close()

• For ESP8266 / ESP32 auto connections

from db_scripts import ubrainDB as DB

credentials = DB(".credentials")

# write ssid and password
credentials.write("ssid", "password")

# more ssids and passwords for multiple locations
credentials.write("ssid4", "password4")
credentials.write("ssid45", "password45")
credentials.write("ssid60", "password60")

credentials.close()

#  ----------Some time later--------------

# Network connection

def do_connect():

    from db_scripts import ubrainDB as DB
    import network
  
    credentials = DB(".credentials")
    
    sta_if = network.WLAN(network.STA_IF)
    
    if not sta_if.isconnected():
        
        # Get keys and values as bytes objects in a dictionary
        dict_B = credentials.items()
        
        print('connecting to network...')
        sta_if.active(True)
        
        for netw in sta_if.scan():
            # catch ssid from index 0 and
            # compare it with the dictionary keys
            if netw[0] in dict_B.keys():
                sta_if.connect(netw[0], dict_B[netw[0]])
  
        while not sta_if.isconnected():
            pass
        credentials.close()
        print('network config:', sta_if.ifconfig())
do_connect()

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