Search icon CANCEL
Subscription
0
Cart icon
Your Cart (0 item)
Close icon
You have no products in your basket yet
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Conferences
Free Learning
Arrow right icon
Arrow up icon
GO TO TOP
Entity Framework Core Cookbook

You're reading from   Entity Framework Core Cookbook Transactions, stored procedures, query libraries, and more

Arrow left icon
Product type Paperback
Published in Nov 2016
Publisher Packt
ISBN-13 9781785883309
Length 324 pages
Edition 2nd Edition
Arrow right icon
Author (1):
Arrow left icon
Ricardo Peres Ricardo Peres
Author Profile Icon Ricardo Peres
Ricardo Peres
Arrow right icon
View More author details
Toc

Table of Contents (10) Chapters Close

Preface 1. Improving Entity Framework in the Real World FREE CHAPTER 2. Mapping Entities 3. Validation and Changes 4. Transactions and Concurrency Control 5. Querying 6. Advanced Scenarios 7. Performance and Scalability A. Pitfalls Index

Refreshing entities

Because of the first level cache, reloading an entity with modified database values will not refresh it.

Problem

Entity Framework Core, like other Object-Relational Mappers, uses something called a First Level Cache (also known as Identity Map) to keep track of the entities that it knows about. These are entities that were loaded from the database or ones that have been marked for persistence. This, in general, can be regarded as an optimization: when Entity Framework loads the same record over and over again, it does not need to instantiate the entity's class and hydrate it with the values coming from the database.

The problem is, what if the entity's record changes in the database and we wish to refresh the ones we have? For example, this won't work:

//retrieve an entity from the database
var myEntity = ctx.MyEntities.First();
//the entity's record changes in the database
//retrieve the entity again
//unchanged: is returned from the first level cache...
lock icon The rest of the chapter is locked
Register for a free Packt account to unlock a world of extra content!
A free Packt account unlocks extra newsletters, articles, discounted offers, and much more. Start advancing your knowledge today.
Unlock this book and the full library FREE for 7 days
Get unlimited access to 7000+ expert-authored eBooks and videos courses covering every tech area you can think of
Renews at $19.99/month. Cancel anytime
Banner background image