1. Entity Framework & LINQ (Language Integrated Query)
MIS Professor Sandvig
7/26/2019
Entity Framework & LINQ (Language Integrated Query)
MIS 324
Professor Sandvig

2. MIS 324 -- Professor Sandvig
7/26/2019
Outline
Entity Framework
Model generation
Scaffolding
Controllers & views
LINQ
Language integrated query

3. What is Entity Framework
MIS Professor Sandvig
7/26/2019
What is Entity Framework
Short version:
Code-less CRUD web interface
Microsoft’s ORM (object relation mapper)
Wizards create model, controller, views from database

4. What is Entity Framework
Dapper lightweight ORM
Fast
Uses standard SQL queries
EF is ORM + code writing wizards

5. EF Model Examines database Example: Generates model of database tables
Database with three tables
VS: Add  New Item  ADO.NET Entity Data Model

6. EF Controller & Views VS: Add > New Scaffolded Item Generates:
Controller with CRUD methods
Views for CRUD

7. EF Controller & Views Run Scaffolding wizard for each table
CRUD Interface

8. Entity Framework VS wizards: Create models from database
Create database from model
Create model and database from db.model
Create MVC controller and views from models

9. Entity Framework Very convenient Scaffolding wizard generates:
Controller
Views
Time: minutes instead of hours
Can add validation, customize view, etc.

10. LINQ Language Integrated Query Used by Entity Framework
Alternative to SQL
Select, sort, filter, etc.
Used by Entity Framework
Eliminates disconnect between database & code

11. MIS 324 -- Professor Sandvig
7/26/2019
LINQ - Intellisense
We have data models
Same as database
LINQ examines models
Provides Intellisense for writing queries

12. LINQ SQL Comparison Example: Sql: LINQ
string sql = "select Id, Fname, Lname, street, city, state
from students
where id
Execute query and map query results to model
LINQ
Student student = db.Students.Find(id);

13. LINQ - Intellisense
See Student LINQ Controller handout

14. LINQ
LINQ can query many collection types:

15. MIS 324 -- Professor Sandvig
7/26/2019
Drawbacks
Microsoft propriety technology
Not useful outside MS universe
LINQ query syntax different than SQL
Better in some ways
Synchronization between database and entity objects
Change database
Rebuild entity objects

16. HW 1
Tutorial HW 1: Getting Started with Entity Framework 6 Database First using MVC 5
Steps:
Create database with three tables:
Students, courses, enrollments
Create EF model with wizard
Create controllers and view with wizard

17. Summary Entity Framework Very handy for CRUD operations
VS wizards create:
Models
Controllers
Views