kelvingakuo

# Run this in your instance that doesn't have a direction connection to the DB

import sqlalchemy
from sshtunnel import SSHTunnelForwarder
import pandas as pd

bastion_url = "ec2-xxxxx.us-west-1.compute.amazonaws.com" # The EC2 instance from which you can connect to RDS

host_prod = "my-db-instance.us-west-1.rds.amazonaws.com" # RDS instance URL
username = "postgres" # DB username

kelvingakuo

from b_tree_index import BTreeIndex
import pprint
if __name__ == "__main__":	
	tbl = [
		{"id": 1, "col_a": 7, "col_b": "A", "TID": 101},
		{"id": 2, "col_a": 7, "col_b": "B", "TID": 102},
		{"id": 3, "col_a": 25, "col_b": "C", "TID": 103},
		{"id": 4, "col_a": 30, "col_b": "D", "TID": 104},
		{"id": 5, "col_a": 4, "col_b": "E", "TID": 105},
		{"id": 6, "col_a": 55, "col_b": "F", "TID": 106},

kelvingakuo

class DoublyLinkedNode(object):
	def __init__(self, value: BPlusTreeNode) -> None:
		""""Init a doubly-linked list node

		Params:
			value (BPlusTreeNode) - The value of the node as a B+ tree node, specifically leaf node
		"""
		if(type(value) != BPlusTreeNode):
			print("The value of the node needs to be a BPlusTreeNode")
		else:

kelvingakuo

def lookup_using_hash_index(self, value: str) -> list:
		""" Return all the rows where the indexed column contains a value

		Params:
			value (str) - The condition

		Returns:
			rows (list) - The matching rows from our table
		"""

kelvingakuo

def create_hash_index(self) -> None:
	""" Creates a hash index of our data based on the column
	"""
	self.hash_table = dict()

	for row in self.table:
		hsh, buck = self.hash_function(row[self.on])
		if(self.hash_table.get(buck, None) is None):
			# Empty bucket, insert TID
			self.hash_table[buck] = []

kelvingakuo

class HashIndex(object):
	def __init__(self, data: List, col: str) -> None:
		""" Init the hash index class

		Params:
			data (list) - Our data as a list of dicts
			col (str) - The column (dict key) to create an index on
		"""
		self.table = data
		self.on = col

kelvingakuo

def query():
	if(accept("SELECT")):
		if(columns()):
			if(accept("FROM")):
				if(name()):
					if(terminal(False)):
						show_tree(tree)
					elif(accept("WHERE")):
						if(condition_list()):
							if(terminal()):

kelvingakuo

def columns():
	if(accept("all_cols", False)):
		return True
	else:
		if(accept("name")):
			if(accept("punctuation", False)):
				columns() # Recursively call self till next token is no longer a punctuation or name
			else:
				return True
		else:

kelvingakuo

def term():
    if(accept("integer", False) or accept("float", False) or accept("name", False)):
        return True

def terminal():
    if(accept("terminal")):
        return True

kelvingakuo

def query():
	""" <query> ::= "SELECT " <columns> " FROM " <name> <terminal> | "SELECT " <columns> " FROM " <name> " WHERE " <conditionList> <terminal>
	"""
	pass
	
def columns():
	""" <columns> ::= (<name> ", ")+ | "*"

	Accepts:
		- *