refactor: change folder structure

02-Project-Based/Session01/Session01 Backend.md

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+
+# 🛠️ Task Checklist
+
+## Preparation 
+### EF Core Code First
+ - [ ] Watch this [video](https://www.youtube.com/watch?v=b8fFRX0T38M&ab_channel=PatrickGod)
+## 🚧 Branching
+- [ ] Create the develop branch
+- [ ] Create the feature/domain-entities branch based on develop 
+## `IEntity.cs`
+- [ ] Create the IEntity **interface**
+📂 Suggested Folder: `Domain/Framework/Interfaces`
+```C#
+public interface IEntity<TKey>
+{
+    public TKey Id { get; set; }
+}
+```
+## `Entity.cs`
+- [ ] Create the Entity **class**
+📂 Suggested Folder: `Domain/Framework/Base`
+```C#
+public class Entity<TKey> : IEntity<TKey>
+{
+    public TKey Id{ get; set; }
+}
+```
+
+
+## Create Entities 
+📂 Suggested Folder: `Domain/Aggregates/[RelatedFolder]`
+Entities represent the core business objects in our domain model. By defining them explicitly and consistently, we ensure that:
+- Our domain logic remains **clear and maintainable**.
+- We follow **Domain-Driven Design (DDD)** principles, keeping the business rules close to the data they govern.
+- All developers have a **standardized structure** to follow, improving code readability and collaboration.
+### Guidelines
+1. **Base Class**
+    - All entities (except join tables) must inherit from `Entity` and explicitly specify the datatype of their `Id`.
+2. **Properties**
+    - Use the **latest version of the ERD** to define properties and relationships.
+3. **Reference Project**
+    - For implementation details, you can refer to this project:  
+        👉 [AlibabaClone-Backend Domain Layer](https://github.com/MehrdadShirvani/AlibabaClone-Backend/tree/develop/AlibabaClone.Domain/Aggregates)
+4. **ERD Reference**
+    - Latest ERD available here:  
+        👉 [Project ERD](obsidian://open?vault=ASP.NET&file=Repo%2FProjectOrientedSessions%2Fdocs%2FAlibabaERD-Version02.pdf)### One Example:
+### Example
+```C#
+public class Account : Entity<long>
+{
+    public required string PhoneNumber { get; set; }
+    public required string Password { set; get; }
+    public string? Email { get; set; }
+    public long? PersonId { get; set; }
+    //...
+}
+```
+
+
+
+
+
+
+
+
+
+## Add Navigation Properties 
+
+Navigation properties in Entity Framework Core (EF Core) **represent relationships between entities**. They allow you to **navigate** (follow) the relationships between different tables using **C# objects** instead of writing SQL joins manually.
+### Add the needed navigation properties inside entities
+- [ ] Figure out what navigation properties are needed based on the ERD, and use this project as a reference:
+https://github.com/MehrdadShirvani/AlibabaClone-Backend/tree/develop/AlibabaClone.Domain/Aggregates
+- [ ] Don't forget to mark all the navigation properties as `virtual`
+
+### **🔹 Examples of Defining Navigation Properties**
+
+
+>These are just examples, and not how the project should look like
+#### **🔹 One-to-Many Example**
+A **Buyer** can have **multiple Tickets**, but each **Ticket** belongs to one **Buyer**.
+```csharp
+public class Buyer
+{
+    public int Id { get; set; }
+    public string Name { get; set; }
+
+    // Navigation Property (One Buyer → Many Tickets)
+    public virtual ICollection<Ticket> Tickets { get; set; } = new List<Ticket>();
+}
+
+public class Ticket
+{
+    public int Id { get; set; }
+    public int BuyerId { get; set; }
+
+    // Navigation Property (Many Tickets → One Buyer)
+    public virtual Buyer Buyer { get; set; }
+}
+```
+
+#### **🔹 One-to-One Example**
+
+A **Ticket** can have only **one Transaction**, and a **Transaction** belongs to exactly **one Ticket**.
+
+```csharp
+public class Ticket
+{
+    public int Id { get; set; }
+
+    // One-to-One Navigation Property
+    public virtual Transaction Transaction { get; set; }
+}
+
+public class Transaction
+{
+    public int Id { get; set; }
+    public int TicketId { get; set; }
+
+    // One-to-One Navigation Property
+    public virtual Ticket Ticket { get; set; }
+}
+```
+
+#### **🔹 Many-to-Many Example**
+
+A **Buyer** can buy **many Tickets**, and each **Ticket** can be bought by **many Buyers** (if resale is allowed).
+
+```csharp
+public class Buyer
+{
+    public int Id { get; set; }
+    public string Name { get; set; }
+
+    // Many-to-Many Navigation Property
+    public virtual ICollection<Ticket> Tickets { get; set; } = new List<Ticket>();
+}
+
+public class Ticket
+{
+    public int Id { get; set; }
+
+    // Many-to-Many Navigation Property
+    public virtual ICollection<Buyer> Buyers { get; set; } = new List<Buyer>();
+}
+```
+
+## Add Packages to Infrastructure Project
+- [ ] Add `Microsoft.EntityFrameworkCore.Proxies` to Infrastructure Project
+## 🚧 Merge
+- [ ] Create a PR and merge the current branch with develop
+# 🧠 Hints & Notes
+- Mark navigation properties `virtual` 
+# 🙌 Acknowledgements
+
+- ChatGPT for snippet refinement and explanations
+
+# 🔍 References
+[[Session01 Additional Info]]
+
+
+
+
+
+
+
+