Upgrading existing migrations

Explicit column attributes

Replace old ColumnProperty flags with IsNullable, IsIdentity and IsUnsigned. Primary, unique, foreign and check constraints belong to the table. GetColumns returns column attributes; use GetTableConstraints for key membership and ordered columns.

Keep the same applied migration versions and effective scope when recompiling. Do not create a new history table merely to make an incompatible source assembly run. Verify the upgrade against a restored database and a fresh database.

One fluent authoring surface

FluentMigration.BuildUp/BuildDown replaces the duplicate legacy builder. Use complete table definitions for keys, explicit operations for indexes, and independent foreign-key update/delete actions. Classic Up/Down migrations remain first-class.

using System.Data;
using DotNetProjects.Migrator.Framework;

[Migration(1)]
public class CreateUsers : Migration
{
    public override void Up()
    {
        Database.AddTable("Users",
            new Column("Id", DbType.Int32) { IsNullable = false },
            new Column("Name", DbType.String, 255),
            new PrimaryKeyConstraint("PK_Users", "Id"));
    }

    public override void Down() => Database.RemoveTable("Users");
}

using DotNetProjects.Migrator.Framework;
using DotNetProjects.Migrator.Framework.Fluent;

[Migration(1)]
public class CreateUsers : FluentMigration
{
    public override void BuildUp(MigrationBuilder migration)
    {
        migration.Create.Table("Users")
            .WithColumn("Id").AsInt32().NotNullable()
            .WithColumn("Name").AsString(255)
            .WithPrimaryKey("PK_Users", "Id");
    }

    public override void BuildDown(MigrationBuilder migration)
        => migration.Delete.Table("Users");
}

Behavior changes to review

Column changes preserve explicit uniqueness; old SQL Server ownership markers no longer control deletion. TimeSpan inputs mean intervals, so convert clock-time inputs to TimeOnly. SQLite GUID defaults use the same blob representation as inserted parameters; unrelated rebuilds preserve existing text defaults.

Read the complete compatibility migration guide for constructor replacements, custom-provider contracts, identity, constraint metadata and collation mappings. Version-specific details live there; these chapters describe the current API.