Double Entry Bookkeeping Database Design - Views vs Derived Tables vs Python Processing

Question

I'm starting to learn a bit about databases, and I've been reading for while about what is the best way to design a database for a simple accounting system with double entry.

For those who are not familiar with accounting, I have a General Journal, and I need to extract a few reports out of it - basically a bunch of SUM IFS (sum this account if this date).

I currently have my journal table designed as a one-liner, but I found this post and this answer that got me thinking.

Some parts of the answer that I would like to understand a bit better:

"...design a data structure that can be the numerical repository for multiple journals..."

• What would be an example of a numerical repository for multiple journals?

"...In a modern RDBMS... ...the General Ledger, and even the specialized subledgers, can become Indexed Views on the Journal, completely eliminating the requirement to code a Posting Process (the step where a Journal transaction is locked and has its account totals transcribed to the various ledgers)..."

• How exactly should I deal with the "Indexed Views" approach?
• Create an indexed view for each Income Statement/Balance Sheet account?
• Maybe materialize a Pivot Table with all the acounts of the Income Statement/Balance Sheet in the columns (don't think that would be reasonable since I have about 150 accounts total)?

My query to extract a stock account (one that accumulates over time, such as Balance Sheet accounts):

SELECT Y, M,(@total := @total + Flow) AS TotalValue
FROM (
        SELECT year(dateacc) AS Y, month(dateacc) AS M, 
            (
                SUM(IF(Credit='Account', valor, 0))-
                SUM(IF(Debit='Account', valor, 0))
            ) AS BS_Account
        FROM journal
        GROUP BY YEAR(dateacc), MONTH(dateacc)
    ) AS T,
(SELECT @total:=0) AS n;

My query to extract a flow account (such as Income Statement Accounts):

SELECT DATE_FORMAT(datecash, '%m-%y') as DATA, 
    (
        SUM(IF(credit='Account', value, 0))-
        SUM(IF(debit='Account', value, 0))
    )
AS Flow 
FROM journal_test
GROUP BY YEAR(datecash), MONTH(datecash)

In a nutshell:

1. What is the best way to design this?
2. View vs Materialized View vs. Derived Table
3. How to approach the general journal vs. subledgers dilema