572 lines
16 KiB
Markdown
572 lines
16 KiB
Markdown
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# 6. Configurations
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## Read the documentation:
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https://learn.microsoft.com/en-us/ef/core/modeling/
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## Create the feature/entity-configurations branch based on develop
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## **1. Where Should You Place Configuration Files?**
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✅ **Best Practice:** Place all configuration files in the **Infrastructure** layer.
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📂 Suggested Folder: `Infrastructure/Configurations`
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Create configuration classes with this format: `[Entity]Configutaion.cs`
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The class should implement the `IEntityTypeConfiguration<[Entity]>`
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### **Reason:**
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- The **Domain layer** should be **clean** (only entities, no database-related logic).
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- The **Infrastructure layer** handles **database interactions**, so configurations belong here.
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---
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## **2. How to Define Keys (Primary Keys & Identity)**
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You **don’t** need to explicitly define the **primary key (PK)** if you follow EF Core conventions (`Id` or `EntityNameId`). However, if you want to be explicit:
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```csharp
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public class TicketConfiguration : IEntityTypeConfiguration<Ticket>
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{
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public void Configure(EntityTypeBuilder<Ticket> builder)
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{
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builder.HasKey(t => t.Id); // Explicitly defining PK (optional)
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builder.Property(t => t.Id)
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.ValueGeneratedOnAdd(); // Sets Identity (auto-increment)
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}
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}
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```
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> 🛑 **NOTE:** If you’re using a GUID as the ID, you might need `.ValueGeneratedNever()` instead.
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---
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## **3. How to Define Foreign Keys?**
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Use `HasOne()` and `WithMany()` for **one-to-many** relationships.
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```csharp
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public class TicketConfiguration : IEntityTypeConfiguration<Ticket>
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{
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public void Configure(EntityTypeBuilder<Ticket> builder)
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{
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builder.HasKey(t => t.Id);
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// Foreign Key - Ticket to Transportation
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builder.HasOne(t => t.Transportation)
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.WithMany(tr => tr.Tickets)
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.HasForeignKey(t => t.TransportationId)
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.OnDelete(DeleteBehavior.Restrict); // Optional: No cascade delete
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}
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}
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```
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---
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## **4. How to Introduce Navigation Properties with Different Names?**
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If your navigation property **doesn’t match** the entity name, you should explicitly specify it using `HasOne()` and `WithMany()`.
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### **Example: Ticket has a Buyer (which is an Account)**
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```csharp
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builder.HasOne(t => t.Buyer) // Navigation property (Ticket → Account)
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.WithMany(a => a.TicketsBought) // Corresponding collection in Account
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.HasForeignKey(t => t.BuyerId);
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```
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> **Tip:** If your navigation property names don't match table names, always define them explicitly in the Fluent API.
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---
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## **5. How to Configure Column Types? (nvarchar, date, etc.)**
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You can **manually specify column types** using `.HasColumnType()`.
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### **All Strings Should Be `nvarchar` with Specific Lengths**
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```csharp
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builder.Property(t => t.TicketNumber)
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.IsRequired()
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.HasMaxLength(20) // Limits nvarchar length
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.HasColumnType("nvarchar(20)");
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```
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### **Store Some DateTime Fields as SQL `DATE` Instead of `DATETIME2`**
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```csharp
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builder.Property(t => t.PurchaseDate)
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.HasColumnType("date"); // Instead of default "datetime2"
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```
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> 🚀 **Best Practice:** Always set **string lengths** to avoid `nvarchar(MAX)`, which hurts performance.
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---
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## **6. How to Define Constraints? (Not Null, Length, etc.)**
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Use `.IsRequired()` for **NOT NULL** and `.HasMaxLength()` for length constraints.
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### **Example: Ticket Number Must Be Unique & Required**
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```csharp
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builder.Property(t => t.TicketNumber)
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.IsRequired() // NOT NULL
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.HasMaxLength(20)
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.HasColumnType("nvarchar(20)");
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builder.HasIndex(t => t.TicketNumber)
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.IsUnique(); // Unique constraint
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```
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---
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## **Final Configuration File Example (TicketConfiguration.cs)**
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Here’s a **complete** example of a configuration file:
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```csharp
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public class TicketConfiguration : IEntityTypeConfiguration<Ticket>
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{
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public void Configure(EntityTypeBuilder<Ticket> builder)
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{
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builder.HasKey(t => t.Id); // Primary Key
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builder.Property(t => t.Id).ValueGeneratedOnAdd(); // Auto-increment
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// Foreign Key Relationships
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builder.HasOne(t => t.Transportation)
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.WithMany(tr => tr.Tickets)
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.HasForeignKey(t => t.TransportationId)
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.OnDelete(DeleteBehavior.Restrict);
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builder.HasOne(t => t.Buyer)
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.WithMany(a => a.TicketsBought)
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.HasForeignKey(t => t.BuyerId);
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// Column Types & Constraints
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builder.Property(t => t.TicketNumber)
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.IsRequired()
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.HasMaxLength(20)
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.HasColumnType("nvarchar(20)");
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builder.HasIndex(t => t.TicketNumber)
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.IsUnique(); // Unique constraint
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builder.Property(t => t.PurchaseDate)
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.HasColumnType("date"); // Store as DATE instead of DATETIME2
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}
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}
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```
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---
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## **Summary & Best Practices**
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✅ **Store Configuration Files in:** `Infrastructure/Configurations`
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✅ **Define Foreign Keys:** Use `HasOne()` and `WithMany()`
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✅ **Explicitly Define Navigation Properties** if the names differ
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✅ **Column Types:** Use `.HasColumnType()` for `nvarchar`, `date`, etc.
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✅ **Constraints:** Use `.IsRequired()`, `.HasMaxLength()`, `.IsUnique()`
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---
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Now you’re all set to configure your entities properly! 🚀 Let me know if you have more questions! 😊
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## Some special cases
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### **1. Join Tables with Multiple IDs**
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In many-to-many relationships, a join table is created to link two entities. This join table typically contains foreign keys referencing the primary keys of the two entities involved in the relationship.
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#### **Example of a Join Table**
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Suppose we have two entities, `Student` and `Course`, and we want to create a many-to-many relationship between them. We'll create a join table called `StudentCourses`.
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#### **Entities**
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```csharp
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public class Student : Entity<long>
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{
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public required string Name { get; set; }
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public virtual ICollection<StudentCourse> StudentCourses { get; set; }
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}
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public class Course : Entity<long>
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{
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public required string Title { get; set; }
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public virtual ICollection<StudentCourse> StudentCourses { get; set; }
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}
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public class StudentCourse
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{
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public long StudentId { get; set; }
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public virtual Student Student { get; set; }
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public long CourseId { get; set; }
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public virtual Course Course { get; set; }
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}
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```
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#### **Configuration for Join Table**
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You would configure the join table using the Fluent API:
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```csharp
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public class StudentCourseConfiguration : IEntityTypeConfiguration<StudentCourse>
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{
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public void Configure(EntityTypeBuilder<StudentCourse> builder)
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{
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// Composite Primary Key
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builder.HasKey(sc => new { sc.StudentId, sc.CourseId });
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// Foreign Key Relationships
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builder.HasOne(sc => sc.Student)
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.WithMany(s => s.StudentCourses)
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.HasForeignKey(sc => sc.StudentId);
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builder.HasOne(sc => sc.Course)
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.WithMany(c => c.StudentCourses)
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.HasForeignKey(sc => sc.CourseId);
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}
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}
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```
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#### **OnModelCreating Method in DbContext**
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In your `DbContext`, you would include:
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```csharp
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protected override void OnModelCreating(ModelBuilder modelBuilder)
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{
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modelBuilder.ApplyConfiguration(new StudentCourseConfiguration());
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}
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```
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#### **Key Points for Join Tables**
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- **Composite Primary Key**: The join table uses a composite key made up of both foreign keys.
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- **Navigation Properties**: This enables navigation from `Student` to `Course` and vice versa.
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---
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### **2. Using GUIDs That Should Be Auto-Generated**
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GUIDs (Globally Unique Identifiers) can be used as primary keys in your entities. In EF Core, you can configure them to auto-generate when a new entity is created.
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#### **Example Entity Using GUID**
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```csharp
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public class SomeEntity
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{
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public Guid Id { get; set; } = Guid.NewGuid(); // Auto-generate GUID
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public string Name { get; set; }
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}
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```
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#### **Configuration for GUID**
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When configuring an entity with a GUID as the primary key, you don’t need a specific setup in the configuration, but you can enforce that the `Id` is generated on addition.
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```csharp
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builder.Property(e => e.Id)
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.ValueGeneratedOnAdd()
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.HasDefaultValueSql("NEWSEQUENTIALID()"); // Optionally use NEWID() for random GUID
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```
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#### **How It Works**
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- **`Guid.NewGuid()`** generates a new GUID when a new entity instance is created.
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- **Database**: If you use `NEWSEQUENTIALID()` in SQL Server, it generates sequential GUIDs, which can improve indexing performance.
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#### **Example Configuration in DbContext**
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Here's how you might define an entity with GUIDs in your `DbContext`:
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```csharp
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public class ApplicationDbContext : DbContext
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{
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public DbSet<SomeEntity> SomeEntities { get; set; }
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protected override void OnModelCreating(ModelBuilder modelBuilder)
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{
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modelBuilder.Entity<SomeEntity>(builder =>
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{
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builder.HasKey(e => e.Id);
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builder.Property(e => e.Id)
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.ValueGeneratedOnAdd()
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.HasDefaultValueSql("NEWSEQUENTIALID()");
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});
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}
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}
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```
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---
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## Create a PR and merge the current branch with develop
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# Summary
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### 📌 **Implementing Database and EF Core in Clean Architecture**
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In **Clean Architecture**, everything should be **modular**, **loosely coupled**, and **separated into layers**. The database-related concerns (entities, repositories, unit of work, configurations, migrations, etc.) belong **primarily** to the **Infrastructure** and **Domain layers**.
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---
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## 🏛 **Layer Breakdown for Database Implementation**
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|**Layer**|**Responsibility**|**Examples**|
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|---|---|---|
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|**Domain**|Business rules & entity models|Entities (POCOs), Value Objects, Interfaces|
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|**Application**|Business logic & use cases|Services, DTOs, CQRS Handlers|
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|**Infrastructure**|Data access, repositories, database configurations|EF Core, Repository, Unit of Work, Configurations|
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|**Presentation**|UI/API layer, controllers, endpoints|ASP.NET Core Controllers, Razor Pages, Blazor|
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---
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## 🛠 **1️⃣ Defining the Domain Layer (Entities and Interfaces)**
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The **Domain Layer** should contain **only business logic and entity definitions**—it should not reference Entity Framework or infrastructure concerns.
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### 📌 **Entities (Domain/Entities)**
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```csharp
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namespace Domain.Entities
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{
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public class Ticket
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{
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public int Id { get; set; }
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public string CustomerName { get; set; } = string.Empty;
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public DateTime PurchaseDate { get; set; }
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public decimal Price { get; set; }
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// Navigation Property
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public int CompanyId { get; set; }
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public virtual Company Company { get; set; } = null!;
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}
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}
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```
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```csharp
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namespace Domain.Entities
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{
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public class Company
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{
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public int Id { get; set; }
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public string Name { get; set; } = string.Empty;
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// Navigation Property
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public virtual ICollection<Ticket> Tickets { get; set; } = new List<Ticket>();
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}
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}
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```
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### 📌 **Repository Interfaces (Domain/Repositories)**
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```csharp
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namespace Domain.Repositories
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{
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public interface IRepository<T> where T : class
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{
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Task<T?> GetByIdAsync(int id);
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Task<IEnumerable<T>> GetAllAsync();
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Task AddAsync(T entity);
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void Remove(T entity);
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}
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}
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```
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```csharp
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namespace Domain.Repositories
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{
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public interface IUnitOfWork
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{
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Task<int> CompleteAsync();
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}
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}
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```
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---
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## 🏗 **2️⃣ Implementing Infrastructure Layer (EF Core, Repositories, Configurations, Migrations)**
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### 📌 **Database Context (Infrastructure/Persistence/AppDbContext.cs)**
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```csharp
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using Domain.Entities;
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using Microsoft.EntityFrameworkCore;
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using System.Reflection;
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namespace Infrastructure.Persistence
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{
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public class AppDbContext : DbContext
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{
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public AppDbContext(DbContextOptions<AppDbContext> options) : base(options) { }
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public DbSet<Ticket> Tickets { get; set; }
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public DbSet<Company> Companies { get; set; }
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protected override void OnModelCreating(ModelBuilder modelBuilder)
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{
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modelBuilder.ApplyConfigurationsFromAssembly(Assembly.GetExecutingAssembly());
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base.OnModelCreating(modelBuilder);
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}
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}
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}
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```
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### 📌 **Entity Configurations (Infrastructure/Persistence/Configurations)**
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EF Core Fluent API is best kept in separate configuration classes.
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```csharp
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using Domain.Entities;
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using Microsoft.EntityFrameworkCore;
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using Microsoft.EntityFrameworkCore.Metadata.Builders;
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namespace Infrastructure.Persistence.Configurations
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{
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public class TicketConfiguration : IEntityTypeConfiguration<Ticket>
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{
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public void Configure(EntityTypeBuilder<Ticket> builder)
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{
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builder.HasKey(t => t.Id);
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builder.Property(t => t.CustomerName)
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.IsRequired()
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.HasMaxLength(100);
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builder.Property(t => t.Price)
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.HasColumnType("decimal(18,2)");
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builder.HasOne(t => t.Company)
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.WithMany(c => c.Tickets)
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.HasForeignKey(t => t.CompanyId);
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}
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}
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}
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```
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---
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### 📌 **Repository Pattern (Infrastructure/Persistence/Repositories)**
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```csharp
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using Domain.Repositories;
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using Microsoft.EntityFrameworkCore;
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namespace Infrastructure.Persistence.Repositories
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{
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public class Repository<T> : IRepository<T> where T : class
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{
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protected readonly AppDbContext _context;
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protected readonly DbSet<T> _dbSet;
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public Repository(AppDbContext context)
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{
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_context = context;
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_dbSet = context.Set<T>();
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}
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public async Task<T?> GetByIdAsync(int id) => await _dbSet.FindAsync(id);
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public async Task<IEnumerable<T>> GetAllAsync() => await _dbSet.ToListAsync();
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public async Task AddAsync(T entity) => await _dbSet.AddAsync(entity);
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public void Remove(T entity) => _dbSet.Remove(entity);
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}
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}
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```
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### 📌 **Unit of Work Implementation**
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```csharp
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using Domain.Repositories;
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using System.Threading.Tasks;
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namespace Infrastructure.Persistence
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{
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public class UnitOfWork : IUnitOfWork
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{
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private readonly AppDbContext _context;
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public UnitOfWork(AppDbContext context)
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{
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_context = context;
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}
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public async Task<int> CompleteAsync()
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{
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return await _context.SaveChangesAsync();
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}
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}
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}
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```
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---
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## 🌍 **3️⃣ Configuring the Database in ASP.NET Core**
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### 📌 **Connection String (appsettings.json)**
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```json
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{
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"ConnectionStrings": {
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"DefaultConnection": "Server=YOUR_SERVER;Database=YourDb;Trusted_Connection=True;MultipleActiveResultSets=true;"
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}
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}
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```
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### 📌 **Registering EF Core in `Program.cs`**
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```csharp
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using Infrastructure.Persistence;
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using Microsoft.EntityFrameworkCore;
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var builder = WebApplication.CreateBuilder(args);
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builder.Services.AddDbContext<AppDbContext>(options =>
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options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));
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// Register repositories and Unit of Work
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builder.Services.AddScoped(typeof(IRepository<>), typeof(Repository<>));
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builder.Services.AddScoped<IUnitOfWork, UnitOfWork>();
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var app = builder.Build();
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app.Run();
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```
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---
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## 🚀 **4️⃣ Migrations and Database Setup**
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### ✅ **Creating Migrations**
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```bash
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dotnet ef migrations add InitialCreate --project Infrastructure --startup-project Presentation
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```
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### ✅ **Applying Migrations**
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```bash
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dotnet ef database update --project Infrastructure --startup-project Presentation
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```
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---
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## 🎯 **Summary**
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|**Component**|**Layer**|**Purpose**|
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|---|---|---|
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|**Entities**|Domain|Business models|
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|**Repository Interfaces**|Domain|Data access abstraction|
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|**AppDbContext & Configurations**|Infrastructure|EF Core setup & Fluent API|
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|**Repositories & UoW**|Infrastructure|Data persistence implementation|
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|**Controllers & Services**|Presentation & Application|API logic|
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|**Connection String**|AppSettings.json|Database configuration|
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---
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## 🏆 **Final Thoughts**
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✅ **This follows Clean Architecture principles**
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✅ **Keeps domain logic independent of EF Core**
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✅ **Repositories and Unit of Work separate infrastructure concerns**
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✅ **DB Context and migrations handled in the right place**
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Would you like to add CQRS or MediatR to this setup? 🚀 |