Tutorials ADO.NET Core Tutorial

Database Migration Strategies — Complete Guide

Database Migration Strategies — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of ADO.NET Core Tutorial on Toolliyo Academy.

8 min read Updated 8/22/2026

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ADO.NET Core Tutorial · Lesson 85 of 100

Database Migration Strategies

Foundations ✓ → SQL & safety ✓ → Production ✓ → Projects

Projects · 4 — Portfolio builds · ~10 min · Module 9: Cloud and DevOps

What is this?

Migrate schema with versioned scripts; keep ADO.NET code compatible during expand/contract.

Why should you care?

ShopNest deploys must survive old API + new columns briefly.

See it live — copy this example

Use a .NET console or API project with SQL Server LocalDB. Run dotnet run after pasting.

-- V042__Orders_Add_Priority.sql
ALTER TABLE Orders ADD Priority INT NOT NULL CONSTRAINT DF_Orders_Priority DEFAULT 0;
-- app still works without reading Priority until next release

What happened?

Expand → migrate data → contract.
Backward-compatible ADO.NET selects.
Never drop columns same release as code still uses them.

Practice next

Add column nullable/default.
Deploy API that writes it.
Backfill.
Feature flag new column read.
Migration checksum in CI.

Remember

Expand/contract. Versioned scripts. Compatible ADO.NET.

ShopNest Priority column

Expand/contract ships safely.

Outcome: Zero-downtime schema change.

Interview prep for this lesson

Practice these questions aloud after reading—each links to a full structured answer.

Mid PDF Detailed

SqlCommand: Used for SQL Server databases. It represents a Transact-SQL?

Short answer: command or stored procedure. Example: SqlCommand command = new SqlCommand("SELECT * FROM Customers", connection); Example code command or stored procedure. Example: SqlCommand command = new SqlCom…

Mid PDF Detailed

OleDbCommand: Used for databases that support OLE DB providers (e.g., MS?

Short answer: Access, Oracle). Example: OleDbCommand command = new OleDbCommand("SELECT * FROM Customers", connection); Example code Access, Oracle). Example: OleDbCommand command = new OleDbCommand("SELEC…

Mid PDF Detailed

Use a DataAdapter to update the database. Set the InsertCommand,?

Short answer: UpdateCommand, and DeleteCommand properties of the DataAdapter to define how data changes should be applied to the database. Real-world example (ShopNest) Always pass order ids with parameters: cmd.Paramete…

Mid PDF Detailed

OdbcCommand: Used for databases that support ODBC (Open Database?

Short answer: Connectivity) drivers. Example: OdbcCommand command = new OdbcCommand("SELECT * FROM Customers", connection); Example code Connectivity) drivers. Example: OdbcCommand command = new OdbcCommand(&qu…

Mid PDF Detailed

Use the DataAdapter's Update() method to push the changes back to the database. Example: SqlDataAdapter adapter = new SqlDataAdapter("SELECT * FROM Customers", connection); SqlCommandBuilder commandBuilder = new SqlCommandBuilder(adapter); // Automatically generates insert, update, delete commands DataSet dataset = new DataSet();

Short answer: dapter.Fill(dataset, "Customers"); // Modify data in the DataSet dataset.Tables["Customers"].Rows[0]["CustomerName"] = "New Name"; // Update the database with the mod…

All course Q&A Practice exams

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