Why should you care?

ShopNest Wallet feature or partner bank integration needs ledger-style Transaction rows — balances must never go negative silently.

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 Account { public int Id { get; set; } public string Number { get; set; } = ""; public decimal Balance { get; set; } public byte[] RowVersion { get; set; } = null!; }
public class Transaction { public int Id { get; set; } public int AccountId { get; set; } public decimal Amount { get; set; } public string Type { get; set; } = ""; public DateTime At { get; set; } }

await using var tx = await db.Database.BeginTransactionAsync();
var acct = await db.Accounts.FindAsync(accountId);
acct!.Balance += amount;
db.Transactions.Add(new Transaction { AccountId = accountId, Amount = amount, Type = "Credit", At = DateTime.UtcNow });
await db.SaveChangesAsync();
await tx.CommitAsync();

What happened?

• Transaction wraps balance update and ledger insert.
• RowVersion on Account enables optimistic concurrency for teller-style updates.
• Decimal mapped with precision.

Practice next

1. Map decimal with HasPrecision(18,2) on money columns.
2. Add RowVersion to Account for concurrent transfer safety.
3. Never use float for money — decimal only.
4. Add transfer between two accounts in single EF transaction.
5. Query daily transaction Sum grouped by Type.

Remember

Banking needs transactions + ledger rows. RowVersion prevents lost updates. decimal(18,2) for all money fields.

ShopNest Wallet ledger

ShopNest stored-value wallet credits Account and inserts Transaction in one EF transaction.

Outcome: Balance always matches sum of transactions for reconciliation jobs.