From bitwarden-software-engineer
Implementing Entity Framework Core repositories and migrations for PostgreSQL, MySQL, and SQLite at Bitwarden. Use when creating or modifying EF repositories, generating EF migrations, or working with non-MSSQL data access in the server repo.
How this skill is triggered — by the user, by Claude, or both
Slash command
/bitwarden-software-engineer:implementing-ef-coreThe summary Claude sees in its skill listing — used to decide when to auto-load this skill
EF implementations live in `src/Infrastructure/EntityFramework/Repositories/`. Each class implements the same interface as its Dapper counterpart. The EF repository uses `DbContext` and LINQ queries instead of stored procedures, but must produce identical behavior.
EF implementations live in src/Infrastructure/EntityFramework/Repositories/. Each class implements the same interface as its Dapper counterpart. The EF repository uses DbContext and LINQ queries instead of stored procedures, but must produce identical behavior.
Bitwarden self-hosted runs on the customer's choice of database. If CipherRepository.GetManyByUserId() returns results in a different order on PostgreSQL than the stored procedure returns on MSSQL, or filters differently, or handles nulls differently — that's a bug. Users switching databases or comparing behavior across environments will see inconsistencies.
The [DatabaseData] integration test attribute runs the same test against all configured databases. This is the primary safety net for parity.
EF Core's LINQ-to-SQL translation varies by provider. Patterns that work on one database may fail on another:
Min() on booleans or implicit string/int conversions that MySQL allows will throwThe pragmatic approach: write clean LINQ, run [DatabaseData] tests, and fix provider-specific failures as they surface rather than trying to predict every edge case.
Run pwsh ef_migrate.ps1 <MigrationName> to generate migrations for all EF targets simultaneously. This creates migration files for each provider (PostgreSQL, MySQL, SQLite).
The EF migration class name must exactly match the MSSQL migration name portion (from the YYYY-MM-DD_##_MigrationName.sql filename). This convention keeps migration history aligned across ORMs and makes it easy to trace which EF migration corresponds to which SQL script.
EF's migration generator makes mechanical decisions that aren't always optimal:
Cipher, OrganizationUser etc. without careful review)Review the generated Up() and Down() methods to ensure they align with the stored procedure migration's intent.
EF navigation properties (e.g., public virtual Organization Organization { get; set; }) affect query generation and lazy loading behavior. Only add them when the stored procedure equivalent also joins those tables. Unnecessary navigation properties cause N+1 queries that don't match the stored procedure's behavior.
EntityTypeConfiguration classesDon't configure entities inline in OnModelCreating. Each entity has a configuration class that defines table mapping, relationships, and constraints. This keeps the DbContext clean and each entity's configuration self-contained.
Entity IDs are generated in application code via CoreHelpers.GenerateComb(), not by the database. Don't configure ValueGeneratedOnAdd() or database-generated defaults for ID columns in EF configuration.
These are the most frequently violated conventions. Claude cannot fetch the linked docs at runtime, so these are inlined here:
EntityTypeConfiguration<T> class per entity — never configure inline in OnModelCreatingYYYY-MM-DD_##_MigrationName.sqlpwsh ef_migrate.ps1 <Name> to generate migrations for all providers simultaneouslyUp() and Down() methods in every generated migration before committingValueGeneratedOnAdd() on ID columns — IDs come from CoreHelpers.GenerateComb() in app code// CORRECT — ID generated in application code
public void Configure(EntityTypeBuilder<Cipher> builder)
{
builder.HasKey(c => c.Id);
// No ValueGeneratedOnAdd — CoreHelpers.GenerateComb() handles this
}
// WRONG — lets database generate IDs, breaks MSSQL parity
public void Configure(EntityTypeBuilder<Cipher> builder)
{
builder.HasKey(c => c.Id);
builder.Property(c => c.Id).ValueGeneratedOnAdd();
}
// CORRECT — only add when the SP also joins this table
public class Cipher
{
public Guid Id { get; set; }
public Guid OrganizationId { get; set; }
// No navigation property — the SP doesn't JOIN Organization
}
// WRONG — causes N+1 queries that don't match SP behavior
public class Cipher
{
public Guid Id { get; set; }
public Guid OrganizationId { get; set; }
public virtual Organization Organization { get; set; }
}
npx claudepluginhub bitwarden/ai-plugins --plugin bitwarden-software-engineerBitwarden database architecture, migrations, and dual-ORM strategy. Use when working with .sql files, stored procedures, EF migrations, or database schema changes.
Generates Entity Framework Core Fluent API configurations mapping domain entities to PostgreSQL tables with relationships, constraints, and value objects.
Entity Framework Core patterns for .NET 10: DbContext configuration, migrations, interceptors, compiled queries, ExecuteUpdateAsync/ExecuteDeleteAsync, value converters, and query optimization.