Entity Framework, Code First, Database First, TPH, TPT, TPC. Table Per Type, Table Per Hierarchy, Table Per Concrete Class, EF Concurrency, EF Relationship, Code First Conventions

1. Entity Framework

2. Agenda
● ORM
● EF Modelling
● LINQ
● EF Inheritance
● EF Concurrency

3. Why Database Layer
Object Impedance Mismatch - RDBMS and OOP
Object Conversions - RDBMS to OOP and OOP to RDBMS
Needs Easy Conversion Process - Rise of ORM

4. ORM?
Many Frameworks - EF, NH, LINQ to SQL
RDBMS to NoSQL Support
Single RDBMS Support to Various RDBMS Support
DB Layer Uniformity Across the Organization

5. Entity Framework - Roadmap

6. EF - Key Terms
Entity
Context - Object Context, Db Context
Deferred Execution
POCO - Plain Old CLR Object
LINQ to Entities, Entity SQL
Mapping, Conceptual Model, Storage Model
Projections

7. EF - Resultant Objects
IEnumerable vs IQueryable

8. EF - Loading
Lazy, Eager Loading and Explicit Loading
Loading Navigation Properties
1. LazyLoadingEnabled = true
2. LazyLoadingEnabled = false & Include(“{Navigation Property}”)
3. LazyLoadingEnabled = false & {Navigation Property}.Load()

9. Modelling - .edmx

10. Modelling - .edmx - Types
Database First
Model First

11. Modelling - Database First
Reverse engineer model in EF Designer
Classes auto-generated from model
Preferred approach for existing database

12. Hands On
Database First - Tables, Stored Procedures, Views, Functions
Update Model

13. Modelling - Model First
Create model in EF Designer
Generate database from model
Classes auto-generated from model
Preferred approach for new database.

14. Hands On
Model First - Create Model, Generate Database
Update Model

15. Modelling - Code First
Define classes and mapping in code
Database created from code
Migrations apply model changes to database
Preferred approach for new database. Generally
preferred in Agile/Scrum

16. Modelling - Fluent Api, Configuration and Conventions
Fluent Api - Chaining Api
Configuration with Fluent Api
Conventions

17. Hands On
Code First - Create Classes with Conventions only
Database Generation
Database Migration

18. EF - CRUD

19. EF - Read Operation

20. EF - Create - Single Record

21. EF - Create - Multiple Records

22. EF - Update Record

23. EF - Delete Record

24. Homework
AddressBook - Design Db and Do CRUD operations on all entities

25. EF - LINQ
Filtering, Ordering
Joining
Grouping

26. EF - LINQ - Filtering, Ordering

27. EF - LINQ - Joining

28. EF - LINQ - Grouping

29. Homework
Full Outer Join Possible?
Use of “let” variable

30. EF - Code First
Conventions
Data Annotations
FluentApi

31. EF - Code First - Conventions
Convention: Table Name
Default: Entity + s (e.g Users)
Convention: Primary Key
Default: Id
Convention: Foreign Key Relation
Default: Entity + Id (e.g SubscriptionId)

32. EF - Code First - Data Annotations
Annotation: Table
=> Table(“{Name”})
Annotation: Key
=> Key
Annotation: ForeignKey
=> ForeignKey(“{Navigation Property”})
=> ForeignKey(“{Property”})

33. EF - Code First - Fluent Api

34. Homework
AddressBook - Design Db and Do CRUD operations on all entities
Executing Raw SQL - Plain, Stored Procedures

35. EF - Inheritance Strategy - TPH

36. EF - Inheritance Strategy - TPH
Needs a column, discriminator, that will used to identify exact type.
Retrieving Type in TPH
Code First Configuration
Gives better performance but there are many duplicate data and nullable columns.

37. EF - Inheritance Strategy - TPT

38. EF - Inheritance Strategy - TPT
Each entity maps to table. So CUD operations are faster
Code First Configuration
Retrieval is slower than TPH as it needs joins with base class/table.

39. EF - Inheritance Strategy - TPC

40. EF - Inheritance Strategy - TPC
Each concrete entity maps to table.
Code First Configuration
Properties of abstract entity are combined with concrete entity and many data/columns duplications.
EDMX designer does not support this mapping. Manual modification is required.

41. EF - Relationships
One to One
One to Many
Many to Many

42. EF - Relationships - One to One

43. EF - Relationships - One to Many

44. EF - Relationships - Many to Many

45. Hands On
One to One
One to Many
Many to Many

46. EF - Concurrency
Optimistic
Pessimistic

47. EF - Concurrency - Optimistic
None: Default and there is no concurrency
Fixed: Original value of concurrency column is included in where part while generating SQL
Rows are not locked. Read operation can be never locked

48. EF - Concurrency - Optimistic
Sample Code

49. EF - Concurrency - Pessimistic
Involves database locking operations. So it is slow
Use Transaction to achieve it
Read operation can be locked

50. Questions

51. Thank you

52. EF - Advance

53. Table Splitting
After little bit experience, it is worth

54. Bounded Contexts
After little bit experience, it is worth

55. EF - Unit Testing
After little bit experience, it is worth

56. EF - Patterns
After little bit experience, it is worth