Ef Core Configuration

EF Core Configuration Generator

Overview

This skill generates Entity Framework Core configurations using Fluent API:

• IEntityTypeConfiguration - Per-entity configuration classes
• Fluent API over attributes - Keep domain clean
• Snake case naming - PostgreSQL convention
• Relationships - One-to-Many, Many-to-Many, One-to-One
• Value Objects - Owned types mapping

Quick Reference

Configuration Structure

/Infrastructure/Configurations/
├── {Entity}Configuration.cs
├── {ChildEntity}Configuration.cs
├── {ValueObject}Configuration.cs
└── OutboxMessageConfiguration.cs

Template: Basic Entity Configuration

// src/{name}.infrastructure/Configurations/{Entity}Configuration.cs
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using {name}.domain.{aggregate};

namespace {name}.infrastructure.configurations;

internal sealed class {Entity}Configuration : IEntityTypeConfiguration<{Entity}>
{
    public void Configure(EntityTypeBuilder<{Entity}> builder)
    {
        // ═══════════════════════════════════════════════════════════════
        // TABLE MAPPING
        // ═══════════════════════════════════════════════════════════════
        builder.ToTable("{entity}");  // snake_case table name

        // ═══════════════════════════════════════════════════════════════
        // PRIMARY KEY
        // ═══════════════════════════════════════════════════════════════
        builder.HasKey(e => e.Id);
        
        builder.Property(e => e.Id)
            .ValueGeneratedNever();  // App generates GUIDs

        // ═══════════════════════════════════════════════════════════════
        // PROPERTIES
        // ═══════════════════════════════════════════════════════════════
        builder.Property(e => e.Name)
            .HasMaxLength(100)
            .IsRequired();

        builder.Property(e => e.Description)
            .HasColumnType("text");  // Unlimited length

        builder.Property(e => e.IsActive)
            .HasDefaultValue(true)
            .IsRequired();

        builder.Property(e => e.CreatedAt)
            .IsRequired()
            .HasDefaultValueSql("CURRENT_TIMESTAMP AT TIME ZONE 'UTC'");

        builder.Property(e => e.UpdatedAt)
            .IsRequired()
            .HasDefaultValueSql("CURRENT_TIMESTAMP AT TIME ZONE 'UTC'");

        // ═══════════════════════════════════════════════════════════════
        // INDEXES
        // ═══════════════════════════════════════════════════════════════
        builder.HasIndex(e => e.Name)
            .IsUnique();

        builder.HasIndex(e => e.OrganizationId);

        builder.HasIndex(e => new { e.OrganizationId, e.Name })
            .IsUnique();
    }
}

Template: Entity with Relationships

// src/{name}.infrastructure/Configurations/{Entity}Configuration.cs
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using {name}.domain.{aggregate};

namespace {name}.infrastructure.configurations;

internal sealed class {Entity}Configuration : IEntityTypeConfiguration<{Entity}>
{
    public void Configure(EntityTypeBuilder<{Entity}> builder)
    {
        builder.ToTable("{entity}");
        builder.HasKey(e => e.Id);

        // ═══════════════════════════════════════════════════════════════
        // FOREIGN KEY PROPERTIES
        // ═══════════════════════════════════════════════════════════════
        builder.Property(e => e.OrganizationId)
            .IsRequired();

        builder.Property(e => e.ParentId);  // Nullable FK

        // ═══════════════════════════════════════════════════════════════
        // ONE-TO-MANY: Parent has many children
        // ═══════════════════════════════════════════════════════════════
        builder.HasMany(e => e.{ChildEntities})
            .WithOne(c => c.{Entity})
            .HasForeignKey(c => c.{Entity}Id)
            .OnDelete(DeleteBehavior.Cascade);

        // ═══════════════════════════════════════════════════════════════
        // MANY-TO-ONE: Entity belongs to Organization
        // ═══════════════════════════════════════════════════════════════
        builder.HasOne(e => e.Organization)
            .WithMany(o => o.{Entities})
            .HasForeignKey(e => e.OrganizationId)
            .OnDelete(DeleteBehavior.Restrict);  // Prevent cascade delete

        // ═══════════════════════════════════════════════════════════════
        // SELF-REFERENCING: Entity has optional parent
        // ═══════════════════════════════════════════════════════════════
        builder.HasOne(e => e.Parent)
            .WithMany(e => e.Children)
            .HasForeignKey(e => e.ParentId)
            .OnDelete(DeleteBehavior.Restrict)
            .IsRequired(false);
    }
}

Template: Child Entity Configuration

// src/{name}.infrastructure/Configurations/{ChildEntity}Configuration.cs
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using {name}.domain.{aggregate};

namespace {name}.infrastructure.configurations;

internal sealed class {ChildEntity}Configuration : IEntityTypeConfiguration<{ChildEntity}>
{
    public void Configure(EntityTypeBuilder<{ChildEntity}> builder)
    {
        builder.ToTable("{child_entity}");
        
        builder.HasKey(c => c.Id);
        
        builder.Property(c => c.Id)
            .ValueGeneratedNever();

        builder.Property(c => c.{Parent}Id)
            .IsRequired();

        builder.Property(c => c.Name)
            .HasMaxLength(100)
            .IsRequired();

        builder.Property(c => c.SortOrder)
            .IsRequired()
            .HasDefaultValue(0);

        builder.Property(c => c.CreatedAt)
            .IsRequired()
            .HasDefaultValueSql("CURRENT_TIMESTAMP AT TIME ZONE 'UTC'");

        // Relationship defined from parent side, but can also define here
        builder.HasOne(c => c.{Parent})
            .WithMany(p => p.{ChildEntities})
            .HasForeignKey(c => c.{Parent}Id)
            .OnDelete(DeleteBehavior.Cascade);

        // Composite unique constraint
        builder.HasIndex(c => new { c.{Parent}Id, c.Name })
            .IsUnique();

        builder.HasIndex(c => new { c.{Parent}Id, c.SortOrder });
    }
}

Template: Many-to-Many Relationship

// src/{name}.infrastructure/Configurations/User{Entity}Configuration.cs
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using {name}.domain.{aggregate};

namespace {name}.infrastructure.configurations;

// Join entity for many-to-many
internal sealed class User{Entity}Configuration : IEntityTypeConfiguration<User{Entity}>
{
    public void Configure(EntityTypeBuilder<User{Entity}> builder)
    {
        builder.ToTable("user_{entity}");

        // Composite primary key
        builder.HasKey(ue => new { ue.UserId, ue.{Entity}Id });

        // Or with separate ID
        // builder.HasKey(ue => ue.Id);
        // builder.HasIndex(ue => new { ue.UserId, ue.{Entity}Id }).IsUnique();

        builder.Property(ue => ue.UserId)
            .IsRequired();

        builder.Property(ue => ue.{Entity}Id)
            .IsRequired();

        builder.Property(ue => ue.IsManager)
            .HasDefaultValue(false);

        builder.Property(ue => ue.CreatedAt)
            .HasDefaultValueSql("CURRENT_TIMESTAMP AT TIME ZONE 'UTC'");

        // Relationships
        builder.HasOne(ue => ue.User)
            .WithMany(u => u.User{Entities})
            .HasForeignKey(ue => ue.UserId)
            .OnDelete(DeleteBehavior.Cascade);

        builder.HasOne(ue => ue.{Entity})
            .WithMany(e => e.User{Entities})
            .HasForeignKey(ue => ue.{Entity}Id)
            .OnDelete(DeleteBehavior.Cascade);
    }
}

Template: Value Object as Owned Type

// src/{name}.infrastructure/Configurations/{Entity}Configuration.cs
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using {name}.domain.{aggregate};

namespace {name}.infrastructure.configurations;

internal sealed class {Entity}Configuration : IEntityTypeConfiguration<{Entity}>
{
    public void Configure(EntityTypeBuilder<{Entity}> builder)
    {
        builder.ToTable("{entity}");
        builder.HasKey(e => e.Id);

        // ═══════════════════════════════════════════════════════════════
        // VALUE OBJECT: Email (stored in same table)
        // ═══════════════════════════════════════════════════════════════
        builder.OwnsOne(e => e.Email, emailBuilder =>
        {
            emailBuilder.Property(email => email.Value)
                .HasColumnName("email")
                .HasMaxLength(255)
                .IsRequired();

            emailBuilder.HasIndex(email => email.Value)
                .IsUnique();
        });

        // ═══════════════════════════════════════════════════════════════
        // VALUE OBJECT: Address (multiple columns)
        // ═══════════════════════════════════════════════════════════════
        builder.OwnsOne(e => e.Address, addressBuilder =>
        {
            addressBuilder.Property(a => a.Street)
                .HasColumnName("address_street")
                .HasMaxLength(200);

            addressBuilder.Property(a => a.City)
                .HasColumnName("address_city")
                .HasMaxLength(100);

            addressBuilder.Property(a => a.State)
                .HasColumnName("address_state")
                .HasMaxLength(50);

            addressBuilder.Property(a => a.ZipCode)
                .HasColumnName("address_zip_code")
                .HasMaxLength(20);

            addressBuilder.Property(a => a.Country)
                .HasColumnName("address_country")
                .HasMaxLength(100);
        });

        // ═══════════════════════════════════════════════════════════════
        // VALUE OBJECT: Money
        // ═══════════════════════════════════════════════════════════════
        builder.OwnsOne(e => e.Price, priceBuilder =>
        {
            priceBuilder.Property(m => m.Amount)
                .HasColumnName("price_amount")
                .HasColumnType("numeric(18,2)")
                .IsRequired();

            priceBuilder.Property(m => m.Currency)
                .HasColumnName("price_currency")
                .HasMaxLength(3)
                .IsRequired();
        });
    }
}

Template: Enum Mapping

// src/{name}.infrastructure/Configurations/{Entity}Configuration.cs
internal sealed class {Entity}Configuration : IEntityTypeConfiguration<{Entity}>
{
    public void Configure(EntityTypeBuilder<{Entity}> builder)
    {
        // ═══════════════════════════════════════════════════════════════
        // ENUM AS STRING
        // ═══════════════════════════════════════════════════════════════
        builder.Property(e => e.Status)
            .HasConversion<string>()  // Store as string
            .HasMaxLength(50)
            .IsRequired();

        // ═══════════════════════════════════════════════════════════════
        // ENUM AS INTEGER (default)
        // ═══════════════════════════════════════════════════════════════
        builder.Property(e => e.Priority)
            .HasConversion<int>();  // Store as int

        // ═══════════════════════════════════════════════════════════════
        // CUSTOM CONVERSION
        // ═══════════════════════════════════════════════════════════════
        builder.Property(e => e.Type)
            .HasConversion(
                v => v.ToString().ToLowerInvariant(),
                v => Enum.Parse<EntityType>(v, true))
            .HasMaxLength(50);
    }
}

Template: Audit Fields with Shadow Properties

// src/{name}.infrastructure/Configurations/{Entity}Configuration.cs
internal sealed class {Entity}Configuration : IEntityTypeConfiguration<{Entity}>
{
    public void Configure(EntityTypeBuilder<{Entity}> builder)
    {
        builder.ToTable("{entity}");

        // ═══════════════════════════════════════════════════════════════
        // SHADOW PROPERTIES (not on domain entity)
        // ═══════════════════════════════════════════════════════════════
        builder.Property<DateTime>("CreatedAt")
            .IsRequired()
            .HasDefaultValueSql("CURRENT_TIMESTAMP AT TIME ZONE 'UTC'");

        builder.Property<DateTime>("UpdatedAt")
            .IsRequired()
            .HasDefaultValueSql("CURRENT_TIMESTAMP AT TIME ZONE 'UTC'");

        builder.Property<string>("CreatedBy")
            .HasMaxLength(100);

        builder.Property<string>("UpdatedBy")
            .HasMaxLength(100);

        builder.Property<uint>("Version")
            .IsRowVersion();  // Concurrency token
    }
}

Template: Soft Delete Configuration

// src/{name}.infrastructure/Configurations/{Entity}Configuration.cs
internal sealed class {Entity}Configuration : IEntityTypeConfiguration<{Entity}>
{
    public void Configure(EntityTypeBuilder<{Entity}> builder)
    {
        builder.ToTable("{entity}");

        // Soft delete property
        builder.Property(e => e.IsDeleted)
            .HasDefaultValue(false)
            .IsRequired();

        builder.Property(e => e.DeletedAt);

        // ═══════════════════════════════════════════════════════════════
        // GLOBAL QUERY FILTER (excludes soft-deleted)
        // ═══════════════════════════════════════════════════════════════
        builder.HasQueryFilter(e => !e.IsDeleted);

        // Index for soft delete queries
        builder.HasIndex(e => e.IsDeleted);
    }
}

Template: JSON Column (PostgreSQL)

// src/{name}.infrastructure/Configurations/{Entity}Configuration.cs
internal sealed class {Entity}Configuration : IEntityTypeConfiguration<{Entity}>
{
    public void Configure(EntityTypeBuilder<{Entity}> builder)
    {
        builder.ToTable("{entity}");

        // ═══════════════════════════════════════════════════════════════
        // JSON COLUMN (PostgreSQL JSONB)
        // ═══════════════════════════════════════════════════════════════
        builder.Property(e => e.Metadata)
            .HasColumnType("jsonb")
            .HasConversion(
                v => JsonSerializer.Serialize(v, (JsonSerializerOptions?)null),
                v => JsonSerializer.Deserialize<Dictionary<string, object>>(v, (JsonSerializerOptions?)null)!);

        // Or for owned types in JSON
        builder.OwnsOne(e => e.Settings, settingsBuilder =>
        {
            settingsBuilder.ToJson();  // EF Core 7+
            settingsBuilder.Property(s => s.NotificationsEnabled);
            settingsBuilder.Property(s => s.Theme);
        });
    }
}

Template: Outbox Message Configuration

// src/{name}.infrastructure/Configurations/OutboxMessageConfiguration.cs
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using {name}.infrastructure.outbox;

namespace {name}.infrastructure.configurations;

internal sealed class OutboxMessageConfiguration : IEntityTypeConfiguration<OutboxMessage>
{
    public void Configure(EntityTypeBuilder<OutboxMessage> builder)
    {
        builder.ToTable("outbox_message");

        builder.HasKey(o => o.Id);

        builder.Property(o => o.Id)
            .ValueGeneratedNever();

        builder.Property(o => o.OccurredOnUtc)
            .IsRequired();

        builder.Property(o => o.Type)
            .HasMaxLength(500)
            .IsRequired();

        builder.Property(o => o.Content)
            .HasColumnType("jsonb")
            .IsRequired();

        builder.Property(o => o.ProcessedOnUtc);

        builder.Property(o => o.Error)
            .HasColumnType("text");

        // Index for processing unprocessed messages
        builder.HasIndex(o => o.ProcessedOnUtc)
            .HasFilter("processed_on_utc IS NULL");
    }
}

PostgreSQL Specific Configurations

Snake Case Naming Convention

// In DependencyInjection.cs
services.AddDbContext<ApplicationDbContext>(options =>
{
    options.UseNpgsql(connectionString)
           .UseSnakeCaseNamingConvention();  // Requires EFCore.NamingConventions
});

Column Types Reference

ApplicationDbContext Setup

// src/{name}.infrastructure/ApplicationDbContext.cs
using Microsoft.EntityFrameworkCore;
using {name}.domain.abstractions;

namespace {name}.infrastructure;

public sealed class ApplicationDbContext : DbContext, IUnitOfWork
{
    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
        : base(options)
    {
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        // Apply all configurations from assembly
        modelBuilder.ApplyConfigurationsFromAssembly(
            typeof(ApplicationDbContext).Assembly);

        base.OnModelCreating(modelBuilder);
    }

    public override async Task<int> SaveChangesAsync(CancellationToken cancellationToken = default)
    {
        // Add domain events to outbox
        AddDomainEventsAsOutboxMessages();
        
        // Update audit fields
        UpdateAuditFields();

        return await base.SaveChangesAsync(cancellationToken);
    }

    private void UpdateAuditFields()
    {
        var entries = ChangeTracker.Entries()
            .Where(e => e.State is EntityState.Added or EntityState.Modified);

        foreach (var entry in entries)
        {
            if (entry.State == EntityState.Added)
            {
                entry.Property("CreatedAt").CurrentValue = DateTime.UtcNow;
            }

            entry.Property("UpdatedAt").CurrentValue = DateTime.UtcNow;
        }
    }
}

Critical Rules

1. Use Fluent API, not attributes - Keep domain clean
2. Configuration per entity - One file per IEntityTypeConfiguration<T>
3. Snake case for PostgreSQL - Use naming convention package
4. ValueGeneratedNever for GUIDs - App generates IDs
5. Explicit column types - Don't rely on conventions
6. Configure relationships from one side - Avoid duplication
7. Use delete behaviors thoughtfully - Cascade vs Restrict
8. Index foreign keys - EF Core doesn't auto-index FKs
9. Use query filters for soft delete - Consistent filtering
10. Value objects as owned types - OwnsOne for value objects

Anti-Patterns to Avoid

// ❌ WRONG: Data annotations on domain
public class User
{
    [Key]
    public Guid Id { get; set; }
    
    [Required]
    [MaxLength(100)]
    public string Name { get; set; }  // Pollutes domain!
}

// ✅ CORRECT: Fluent API in configuration
builder.Property(u => u.Name).HasMaxLength(100).IsRequired();

// ❌ WRONG: Not specifying string length
builder.Property(e => e.Name);  // Defaults to MAX!

// ✅ CORRECT: Always specify max length
builder.Property(e => e.Name).HasMaxLength(100);

// ❌ WRONG: Auto-increment for GUIDs
builder.Property(e => e.Id).ValueGeneratedOnAdd();

// ✅ CORRECT: App generates GUIDs
builder.Property(e => e.Id).ValueGeneratedNever();

// ❌ WRONG: No cascade strategy
builder.HasMany(e => e.Children).WithOne();

// ✅ CORRECT: Explicit delete behavior
builder.HasMany(e => e.Children)
    .WithOne(c => c.Parent)
    .OnDelete(DeleteBehavior.Cascade);

EF Core Migrations

Installing Migration Tools

# Install global tool (recommended)
dotnet tool install --global dotnet-ef

# Update tool
dotnet tool update --global dotnet-ef

# Add design package to project
dotnet add package Microsoft.EntityFrameworkCore.Design

Creating Migrations

# Create a new migration
dotnet ef migrations add InitialCreate

# Create migration with specific context
dotnet ef migrations add AddUsers --context ApplicationDbContext

# Create migration with output directory
dotnet ef migrations add AddOrders --output-dir Data/Migrations

Applying Migrations

# Update database to latest migration
dotnet ef database update

# Update to specific migration
dotnet ef database update AddUsers

# Rollback all migrations (revert to empty database)
dotnet ef database update 0

# Update with connection string
dotnet ef database update --connection "Host=localhost;Database=mydb;Username=postgres;Password=postgres"

Viewing Migrations

# List all migrations
dotnet ef migrations list

# View SQL for a migration
dotnet ef migrations script

# Generate SQL from one migration to another
dotnet ef migrations script AddUsers AddOrders

# Generate idempotent SQL (checks migration history)
dotnet ef migrations script --idempotent

# Generate SQL to file
dotnet ef migrations script --output migration.sql

Removing Migrations

# Remove last migration (if not applied)
dotnet ef migrations remove

# Force remove (even if applied - dangerous!)
dotnet ef migrations remove --force

Database Operations

# Drop database
dotnet ef database drop

# Drop database without confirmation
dotnet ef database drop --force

# Get database info
dotnet ef dbcontext info

# List available DbContext types
dotnet ef dbcontext list

Migration Bundles (Recommended for Production)

# Create self-contained migration bundle
dotnet ef migrations bundle --self-contained -r linux-x64

# Execute bundle
./efbundle --connection "Host=prod-server;Database=mydb;..."

# Create bundle for specific migration
dotnet ef migrations bundle --target-migration AddUsers

Visual Studio Package Manager Console

# Install tools
Install-Package Microsoft.EntityFrameworkCore.Tools

# Create migration
Add-Migration InitialCreate

# Update database
Update-Database

# Rollback to specific migration
Update-Database AddUsers

# Rollback all migrations
Update-Database 0

# Remove last migration
Remove-Migration

# Generate SQL script
Script-Migration

# Generate idempotent script
Script-Migration -Idempotent

Migration Best Practices

1. Review Generated Migrations

Always review migration files before applying:

// migrations/20240101000000_AddUsers.cs
public partial class AddUsers : Migration
{
    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.CreateTable(
            name: "users",
            columns: table => new
            {
                id = table.Column<Guid>(nullable: false),
                email = table.Column<string>(maxLength: 255, nullable: false),
                created_at = table.Column<DateTime>(nullable: false,
                    defaultValueSql: "CURRENT_TIMESTAMP AT TIME ZONE 'UTC'")
            },
            constraints: table =>
            {
                table.PrimaryKey("pk_users", x => x.id);
            });

        migrationBuilder.CreateIndex(
            name: "ix_users_email",
            table: "users",
            column: "email",
            unique: true);
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.DropTable(name: "users");
    }
}

2. Custom Migration Operations

public partial class AddCustomFunction : Migration
{
    protected override void Up(MigrationBuilder migrationBuilder)
    {
        // Custom SQL
        migrationBuilder.Sql(@"
            CREATE OR REPLACE FUNCTION update_updated_at_column()
            RETURNS TRIGGER AS $$
            BEGIN
                NEW.updated_at = CURRENT_TIMESTAMP AT TIME ZONE 'UTC';
                RETURN NEW;
            END;
            $$ language 'plpgsql';
        ");

        // Create trigger
        migrationBuilder.Sql(@"
            CREATE TRIGGER update_users_updated_at 
            BEFORE UPDATE ON users
            FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();
        ");
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.Sql("DROP TRIGGER IF EXISTS update_users_updated_at ON users;");
        migrationBuilder.Sql("DROP FUNCTION IF EXISTS update_updated_at_column();");
    }
}

3. Data Migrations

public partial class SeedInitialData : Migration
{
    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.InsertData(
            table: "roles",
            columns: new[] { "id", "name", "created_at" },
            values: new object[,]
            {
                { Guid.NewGuid(), "Admin", DateTime.UtcNow },
                { Guid.NewGuid(), "User", DateTime.UtcNow }
            });
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.DeleteData(
            table: "roles",
            keyColumn: "name",
            keyValues: new object[] { "Admin", "User" });
    }
}

4. Production Deployment Strategies

Option 1: Migration Bundles (Recommended)

# Build bundle in CI/CD
dotnet ef migrations bundle --self-contained -r linux-x64 -o efbundle

# Deploy and run
./efbundle --connection $CONNECTION_STRING

Option 2: SQL Scripts

# Generate idempotent script
dotnet ef migrations script --idempotent -o migration.sql

# Review and apply via database tools
psql -h hostname -U username -d database -f migration.sql

Option 3: Startup Migration (Development Only)

// Program.cs - NOT for production!
using (var scope = app.Services.CreateScope())
{
    var db = scope.ServiceProvider.GetRequiredService<ApplicationDbContext>();
    db.Database.Migrate();  // Applies pending migrations
}

5. Migration Naming Conventions

# Good names (descriptive)
dotnet ef migrations add AddUserEmailIndex
dotnet ef migrations add CreateOrdersTable
dotnet ef migrations add AddAuditFieldsToProducts
dotnet ef migrations add SeedInitialRoles

# Bad names (vague)
dotnet ef migrations add Update1
dotnet ef migrations add Fix
dotnet ef migrations add Changes

6. Handling Migration Conflicts

# If migration conflicts occur:
# 1. Pull latest code
git pull

# 2. Remove your local migration
dotnet ef migrations remove

# 3. Create new migration
dotnet ef migrations add YourFeature

# 4. Review and test
dotnet ef database update

PostgreSQL-Specific Migration Tips

Use PostgreSQL Features

protected override void Up(MigrationBuilder migrationBuilder)
{
    // JSONB column
    migrationBuilder.AddColumn<string>(
        name: "metadata",
        table: "products",
        type: "jsonb",
        nullable: true);

    // Array column
    migrationBuilder.AddColumn<string[]>(
        name: "tags",
        table: "products",
        type: "text[]",
        nullable: true);

    // Full-text search
    migrationBuilder.Sql(@"
        ALTER TABLE products 
        ADD COLUMN search_vector tsvector 
        GENERATED ALWAYS AS (
            to_tsvector('english', coalesce(name, '') || ' ' || coalesce(description, ''))
        ) STORED;
    ");

    migrationBuilder.CreateIndex(
        name: "ix_products_search_vector",
        table: "products",
        column: "search_vector")
        .Annotation("Npgsql:IndexMethod", "GIN");
}

Partial Indexes (PostgreSQL)

protected override void Up(MigrationBuilder migrationBuilder)
{
    migrationBuilder.CreateIndex(
        name: "ix_orders_pending",
        table: "orders",
        column: "created_at")
        .Annotation("Npgsql:IndexPredicate", "status = 'Pending'");
}

Troubleshooting

Migration Already Applied

# If migration was applied manually, mark as applied
dotnet ef migrations add AlreadyApplied --no-build
dotnet ef database update --no-build

Reset Development Database

# Drop and recreate
dotnet ef database drop --force
dotnet ef database update

Check Migration Status

# See which migrations are applied
dotnet ef migrations list

# Check database connection
dotnet ef dbcontext info

Migration Fails Midway

# Rollback to previous migration
dotnet ef database update PreviousMigrationName

# Fix issue and try again
dotnet ef database update

Related Skills

• domain-entity-generator - Generate entities to configure
• repository-pattern - Use configurations with repositories
• dotnet-clean-architecture - Infrastructure layer placement
• 23-postgresql-best-practices - PostgreSQL-specific optimizations