Why should you care?

ShopNest marketplace settlements need ledger JournalEntry per seller payout — finance requires balanced debits and credits.

See it live — copy this example

Paste into a .NET project with EF Core packages, then run with LocalDB/SQL Server (dotnet ef / dotnet run).

public class JournalEntry { public int Id { get; set; } public DateTime Date { get; set; } public ICollection<JournalLine> Lines { get; set; } = new List<JournalLine>(); }
public class JournalLine { public int Id { get; set; } public int AccountId { get; set; } public decimal Debit { get; set; } public decimal Credit { get; set; } }

var entry = new JournalEntry { Date = DateTime.UtcNow, Lines = {
    new JournalLine { AccountId = cashAcct, Debit = 1000, Credit = 0 },
    new JournalLine { AccountId = revenueAcct, Debit = 0, Credit = 1000 }
}};
if (entry.Lines.Sum(l => l.Debit) != entry.Lines.Sum(l => l.Credit)) throw new InvalidOperationException();
db.JournalEntries.Add(entry);
await db.SaveChangesAsync();

What happened?

• JournalEntry groups balanced lines.
• Domain check ensures debits equal credits before EF insert.
• AccountId links to chart of accounts.

Practice next

1. Model Account chart with AccountType enum.
2. Validate balance in domain before SaveChanges.
3. Never delete posted entries — append reversing entries.
4. Query trial balance GroupBy AccountId Sum Debit-Credit.
5. Add FiscalPeriod entity and filter entries by open period.

Remember

Double-entry: JournalEntry + JournalLines. Validate debits equal credits before save. Immutable posted entries with reversals only.

ShopNest seller settlement

Nightly job posts JournalEntry balancing cash and seller payable for completed orders.

Outcome: Finance exports balanced entries matching bank reconciliation.