python simple OOP for passing args and decorator

Question

I’m new to OOP, I’m trying to create a class and function that receives names and create the SQL calls for me, like:
df_1 and df_2.
However I want that my class manages it for me, so the args will be just to repeat the names, like: ('table1', 'table2', 'n'..)..

So how can I do this in the best way?
As I’m learning I appreciate explanations

import pandas as pd
from def_funcs import sup  # I got my data base engine from this func
from typing import Tuple, List, Dict

# NON OOP WAY
df_1 = pd.read_sql("""
    select * from table1
    """, sup.start_engine())
print(df_1.columns)

df_2 = pd.read_sql("""
    select * from table2
    """, sup.start_engine())
print(df_2.columns)

OOP WAY << EXPECTED >>

class ExtractDb:
def __init__(self, tbl_name, tables):
    self.tbl_name = tbl_name
    self.get_tables = tables

def get_tables(*args: str) -> Tuple[str]:
    return args

def create_db(self, tbl):
    tbl = self.tbl_name
    tbl = pd.read_sql(self.get_tables, sup.start_engine())
    return tbl
    # print(ExtractDb.get_tables('', '2', '3', '4'))
    print(ExtractDb.create_db())

The output will be the number of tables passed as args within tuples or dict (whatever).

Maybe my code is really messed up, feel free to modify it!!

Asked By: automation_m

||

Source

Answer 1

You can try these two approaches:

Use a simple function

import pandas as pd
from def_funcs import sup  # I got my data base engine from this func
from typing import Tuple, List, Dict

def get_dataframes(tables):
    dataframes = []
    for t in tables:
        sql = f"SELECT * FROM {t}"
        dataframe = pd.read_sql(sql, sup.start_engine())
        dataframes.append(dataframe)
    return dataframes

Use the OOP approach

class ExtractDb:

    def __init__(self, tables):
        self.tables= tables

    def get_tables(*args: str) -> Tuple[str]:
        return args

    def create_db(self, tbl):
        dataframes = []
        for t in self.tables:
            sql = f"SELECT * FROM {t}"
            dataframe = pd.read_sql(sql, sup.start_engine())
            dataframes.append(dataframe)
        return dataframes

Answered By: Daniel Afriyie

python simple OOP for passing args and decorator

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