ef-migrations

name	ef-migrations
description	Create and apply EF Core migrations in Spiderly projects. Use when adding, modifying, or removing entity properties, changing column types, renaming columns, or any database schema change that requires a migration.

EF Migrations

Creating a migration

Run from the Backend directory, using the Migrations console project as startup (avoids DLL locking — no need to stop the running backend):

dotnet ef migrations add <MigrationName> --project <InfrastructureProject> --startup-project <MigrationsProject>

Example:

cd MyApp/Backend
dotnet ef migrations add AddOrderNumberToProduct --project MyApp.Infrastructure --startup-project MyApp.Migrations

Always review the generated migration file before proceeding.

Relationship schema is declarative — let the migration reflect it

Schema produced by relationship attributes ([WithMany] FKs, [M2M] join tables, [WithOne] one-to-one) is configured in the model (OnModelCreating extensions), so the migration just reflects it — you don't hand-write that DDL. In particular, a one-to-one ([WithOne]) auto-emits a unique index on the FK: do not add [Index(IsUnique = true)] yourself, and don't hand-write a CREATE UNIQUE INDEX. For an optional 1-1 (nullable FK) the index must allow many NULLs — that's left to provider conventions (Postgres NULLS DISTINCT, SQL Server's auto IS NOT NULL filter), so never add a HasFilter. If the generated migration shows a filtered/NULL-collapsing unique index on a nullable 1-1 FK, something is wrong — investigate rather than editing the migration by hand.

Applying locally

After creating a migration, always apply it to your local database:

dotnet ef database update --project <InfrastructureProject> --startup-project <MigrationsProject>

Data migrations

When a schema change requires data conversion (e.g., converting 0 to NULL after making a column nullable), add migrationBuilder.Sql() calls inside the Up method. Keep them simple and idempotent.

Production

Schema changes are applied to production automatically through the deployment pipeline. Never run DDL (ALTER TABLE, DROP COLUMN, CREATE INDEX, etc.) directly against the production database.

Direct production DB access (via db-query or psql) is only for data queries and data updates (SELECT, INSERT, UPDATE of row values) — not for schema changes.

The Migrations project

Each Spiderly solution includes a lightweight console app (e.g., MyApp.Migrations) specifically for running EF tooling. It exists because the main WebAPI project's DLLs are often locked by the running dev server. Always use it as the --startup-project for dotnet ef commands.