Tutorials ADO.NET Core Tutorial
Payment Processing System — Complete Guide
Payment Processing System — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of ADO.NET Core Tutorial on Toolliyo Academy.
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ADO.NET Core Tutorial · Lesson 96 of 100
Payment Processing System
Foundations ✓ → SQL & safety ✓ → Production ✓ → Projects
Projects · 4 — Portfolio builds · ~10 min · Module 10: Real-World Enterprise Projects
What is this?
Payments capture/refund via procs in transactions with idempotency keys stored in SQL.
Why should you care?
ShopNest must survive client retries without double capture.
See it live — copy this example
Use a .NET console or API project with SQL Server LocalDB. Run dotnet run after pasting.
cmd.CommandText = "usp_Payments_Capture";
cmd.Parameters.Add("@IdempotencyKey", SqlDbType.UniqueIdentifier).Value = key;
cmd.Parameters.Add("@OrderId", SqlDbType.Int).Value = orderId;
await cmd.ExecuteNonQueryAsync(ct);What happened?
- Idempotency unique index.
- Proc no-ops on replay.
- Log outcomes.
Practice next
- Idempotency table/constraint.
- Capture proc.
- Retry same key.
- Refund path.
- Timeout then status poll.
Remember
Idempotent capture. Proc + unique key. Safe retries.
ShopNest capture idempotency
Double POST captures once.
Outcome: Finance trusts payment rows.
Interview prep for this lesson
Practice these questions aloud after reading—each links to a full structured answer.
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