I just made a change to the database schema, but now the team needs it for my feature to work. How can I keep track of my database changes and communicate them to the rest of the team? Migrations give a structured way to structurally alter your database structure as your application evolves . . . structurally. They also provide a way for everyone on the team: developers, testers, CI admins, DBAs, etc, to apply the latest changes wherever they are needed - with uniformity and low friction. Fluent Migrations for .NET provide a discoverable, human readable API that supports dozens of different databases (including SQL Server, PostgreSQL, Oracle). Topics covered in this session: * Why you should use migrations * How to write fluent migrations * A look behind the scenes of how fluent migrations work * Drawbacks/downsides to using migrations * Other migration options for EF and NoSQL (Couchbase) Ad hoc SQL scripts make you want to flip a desk? Keep your team on the same page with fluent migrations. (This session will briefly mention EF Migrations, but is not primarily about EF).

1. To Put Your Schema in Git
July 2023
Matthew D. Groves | DevRel Engineer
Using Fluent Migrations

2. 2
My Migration Story
The Bad Old Days

3. 3
Who am I?
• Matthew D. Groves
• Couchbase, DevRel Engineer
• Author (Manning, Apress, Pluralsight)
• Streamer: https://twitch.tv/matthewdgroves
• https://twitter.com/mgroves
• C# Advent creator

4. To Put Your Schema in Git
August 2023
Matthew D. Groves | DevRel Engineer
Using Fluent Migrations

5. 01/
02/
03/
04/
05/
06/
Intro
Why (Fluent) Migration?
Demo
Select Features
Why NOT use it?
NoSQL
Agenda
07/ Next Steps

6. 6
2 Why (Fluent) Migration?

7. 7
My Migration Story
The Bad Old Days

8. 8
My Migration Story
The Bad Old Days

9. 9
My Migration Story
The Bad Old Days

10. 10
What is Migration?
1. Write a script to make change(s) to a database schema
• E.g. "create a table" or "alter a table"
2. Script generally corresponds to a feature change in the code base
3. Commit the script with the feature change to source control
4. Run all scripts one-by-one and/or compile all scripts into a single script
NOT migration of data from one database to another

11. 11
Why use Migration?
• Version Control 📂⏰
• Automation ⚙⏰
• Documentation 📄📕
• Collaboration ⏰👥

12. 12
Why use FluentMigrator?
• 💡 Fluent, intuitive. Discoverable API
• 🔗C# / .NET
• 🌐 Database independence
• ⏰ Automation
Create.Slide("BulletPoints").With("Emojis")

13. 13
3 Getting Started

14. Demo

15. 15
4 FluentMigrator
Features

16. 16
using FluentMigrator;
using System;
namespace YourCompany.YourProduct.Database.Maintenance
{
public class TagNames
{
public const string Development = nameof(Development);
}
[Tags(TagNames.Development)]
[Maintenance(MigrationStage.BeforeAll, TransactionBehavior.None)]
public class DevBeforeAll : ForwardOnlyMigration
{
public override void Up()
{
System.Console.WriteLine($"Tag=[{TagNames.Development}] Stage=[{MigrationStage.BeforeAll}]");
}
}
}
Maintenance Migrations
Run Logic Every Time

17. 17
[Tags("DK", "NL", "UK")]
[Tags("Staging", "Production")]
[Migration(1)]
public class DoSomeStuffToEuropeanStagingAndProdDbs : Migration
{
/* ... etc ... */
}
Tags
Filtering Migrations

18. 18
/// <summary>
/// Mark all migrations with this INSTEAD of [Migration].
/// </summary>
public class MyCustomMigrationAttribute : FluentMigrator.MigrationAttribute
{
public MyCustomMigrationAttribute(int branchNumber, int year, int month, int day, int hour, int minute, string author)
: base(CalculateValue(branchNumber, year, month, day, hour, minute))
{
this.Author = author;
}
public string Author { get; private set; }
private static long CalculateValue(int branchNumber, int year, int month, int day, int hour, int minute)
{
return branchNumber * 1000000000000L + year * 100000000L + month * 1000000L + day * 10000L + hour * 100L + minute;
}
}
[MyCustomMigration(author: "Scott Stafford", branchNumber: 12, year: 2012, month: 8, day: 7, hour: 14, minute: 01)]
public class TestLcmpMigration : Migration
{
public override void Down() { /* ... */ }
public override void Up() { /* ... */ }
}
Enforce Version Numbering
One Standard for the Whole Team

19. 19
public class YourConventionSet : IConventionSet
{
public YourConventionSet() : this(new DefaultConventionSet()) { }
public YourConventionSet(IConventionSet innerConventionSet)
{
ForeignKeyConventions = new List<IForeignKeyConvention>()
{
/* This is where you do your stuff */
new YourCustomDefaultForeignKeyNameConvention(),
innerConventionSet.SchemaConvention,
};
ColumnsConventions = innerConventionSet.ColumnsConventions;
ConstraintConventions = innerConventionSet.ConstraintConventions;
IndexConventions = innerConventionSet.IndexConventions;
SequenceConventions = innerConventionSet.SequenceConventions;
AutoNameConventions = innerConventionSet.AutoNameConventions;
SchemaConvention = innerConventionSet.SchemaConvention;
RootPathConvention = innerConventionSet.RootPathConvention;
}
/// ... etc ...
}
Naming Conventions
What if my tables are named with GIANT_SNAKE_CASE?

20. 20
[Migration(201207080104)]
public class RenameTableWithSchema : AutoReversingMigration
{
public override void Up()
{
Rename.Table("TestTable2")
.InSchema("TestSchema")
.To("TestTable'3");
}
}
Auto-Reversing
Such a Down()er

21. 21
dotnet-fm migrate
-m Session
-p sqlserver2012
-c "<connection string here>"
-a "./path/to/YourMigrations.dll"
Transactions
Begin / Commit / Rollback

22. 22
5 Why NOT use it?

23. 23
Top 5 Reasons NOT to use Fluent Migrator
Number 3 will SHOCK you

24. 24
Why NOT use FluentMigrator?
1. 💧 All Abstractions are leaky
5 Reasons

25. 25
Why NOT use FluentMigrator?
1. 💧 All Abstractions are leaky
2. ⏰It's C#. How does your DBA feel about it?
5 Reasons

26. 26
Why NOT use FluentMigrator?
1. 💧 All Abstractions are leaky
2. ⏰ It's C#. How does your DBA feel about it?
3. ⚙ Sprocs / views / triggers
5 Reasons

27. 27
Why NOT use FluentMigrator?
1. 💧 All Abstractions are leaky
2. ⏰ It's C#. How does your DBA feel about it?
3. ⚙ Sprocs / views / triggers
4. ♊Potential duplication of concerns
5 Reasons

28. 28
Why NOT use FluentMigrator?
1. 💧 All Abstractions are leaky
2. ⏰ It's C#. How does your DBA feel about it?
3. ⚙ Sprocs / views / triggers
4. ♊Potential duplication of concerns
5. 🎯 Database-specific features
5 Reasons

29. 29
6 NoSQL

30. 30
Couchbase is a JSON database
NoSQL = No schema, right?

31. 31
Couchbase is a JSON database
NoSQL = No schema, right?

32. 32
Couchbase is a JSON database
SQL Server Couchbase Note
Server Cluster ➕ Scalability / High Availability / Built-in caching
Catalog (Database) Bucket
Schema Scope Often just "dbo" in SQL Server or "_default" in Couchbase
Table Collection ➖ Pre-defined columns/constraints
Row Document ➕ Flexible JSON
tSQL SQL++ (Previously known as N1QL in Couchbase)
Primary Key Document Key ➖ Compound keys
➖ "No" keys
Index Index

33. 33
NoSQL Support for Fluent Migrator?
Instead of
Create.Table(. . .)
what if there was
Create.Collection(. . .)
?

34. 34
Introducing: NoSQLMigrator

35. 35
[Migration(1)]
public class Migration001_CreateInitialScopeAndCollection : Migrate
{
public override void Up()
{
Create.Scope("myScope")
.WithCollection("myCollection1");
}
public override void Down()
{
Delete.Scope("myScope");
}
}
NoSqlMigrator in Action
Look familiar?

36. 36
7 Next Steps

37. 37
Try FluentMigrator
• https://github.com/mgroves/FluentMigratorDemo
• https://fluentmigrator.github.io/
• dotnet add package FluentMigrator
How to get started

38. 38
Try Couchbase Capella
• Free Playground: https://couchbase.live
• Free Trial (no credit card needed!)
• https://www.couchbase.com/products/capella/
• Ask me about Couchbase!

39. 39
Tell Someone!
• Hashtag it: #DaytonDotNet? #GemCityTech?
• #Couchbase
• https://twitter.com/mgroves
• Tell your team!
• Write, make a video, podcast, etc!
• https://csadvent.christmas
Learn something interesting?

40. THANK YOU