Skip to main content

Main difference between Code First, Model First, Entities First

In one of my latests post I wrote about Hybrid Code First. When I started to write about it I realised that it is not very clear and transparent what does Code First, Database First and Model First are and what are differences between them.
The main scope of this post is to define in a few words each of this mechanisms and what are the main difference between them.
  • Code First - Define the domain first in code. Based on this domain, the database will be created on the fly by Entity Framework. This approach is used very often in combination with DDD (Domain Driven Development)
  • Database First -  Define the database schema first. Based on it, EF generates the code that maps the database to our entities and the access mechanism
  • Model First - Define the model in a design tool. Based on this design, EF will generate the entities and the database structure that is needed
Now, that we know what are the available mechanism to define and map our model, let's see what are the main characteristics of each of this mechanism. 

Code First 
  • Full control to the code
  • No code generated by tools of frameworks
  • DB schema doesn't need to be managed
  • Mapping can be done from the code directly using Fluent API
  • EF designers are not required
  • Changes to database schema will be lost (because the code defines the schema - Except when you are using Hybrid Code First)
  • DB creation is managed 100% by EF
  • No DB knowledge is required (until you have performance problems) 
Model First
  • A designer that can be used to define the model
  • Entities (using t4 template) and DB schema is generated automatically from this designer 
  • For custom POCO configuration or extensibility you will need to use partial classes or modify T4 template
  • No direct control the DB schema that is generated
  • No direct control of POCO entities that are generated 
  • Any change in DB schema will be lost or will cause an error in the EF, because DB is generated using the model defined in the designer
Database First
  • Full control at DB schema
  • Database can be created separately and POCO entities will be generated automatically
  • Existing database can be used without any kind of changes
  • Database schema can be changed without any kind of issues and the entities will be updated 
  • Any additional items on POCO entities will required partial classes or changes of T4 template

There is no best solution. Based on the needs and different context you will prefer to use a specific solution. For example, when you have an existing database you may prefer to use Database First. If you want to have full access to entities than you may prefer Code First.


Popular posts from this blog

ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded

Today blog post will be started with the following error when running DB tests on the CI machine:
threw exception: System.InvalidOperationException: The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' registered in the application config file for the ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded. Make sure that the assembly-qualified name is used and that the assembly is available to the running application. See for more information. at System.Data.Entity.Infrastructure.DependencyResolution.ProviderServicesFactory.GetInstance(String providerTypeName, String providerInvariantName) This error happened only on the Continuous Integration machine. On the devs machines, everything has fine. The classic problem – on my machine it’s working. The CI has the following configuration:

TeamCity.NET 4.51EF 6.0.2VS2013
It seems that there …

How to check in AngularJS if a service was register or not

There are cases when you need to check in a service or a controller was register in AngularJS.
For example a valid use case is when you have the same implementation running on multiple application. In this case, you may want to intercept the HTTP provider and add a custom step there. This step don’t needs to run on all the application, only in the one where the service exist and register.
A solution for this case would be to have a flag in the configuration that specify this. In the core you would have an IF that would check the value of this flag.
Another solution is to check if a specific service was register in AngularJS or not. If the service was register that you would execute your own logic.
To check if a service was register or not in AngularJS container you need to call the ‘has’ method of ‘inhector’. It will return TRUE if the service was register.
if ($injector.has('httpInterceptorService')) { $httpProvider.interceptors.push('httpInterceptorService&#…

Fundamental Books of a Software Engineer (version 2018)

More then six years ago I wrote a blog post about fundamental books that any software engineer (developer) should read. Now it is an excellent time to update this list with new entries.

There are 5 different categories of books, that represent the recommended path. For example, you start with Coding books, after that, you read books about Programming, Design and so on.
There are some books about C++ that I recommend not because you shall know C++, only because the concepts that you can learn from it.


Writing solid codeCode completeProgramming Pearls, more programming pearls(recommended)[NEW] Introduction to Algorithms


Refactoring (M. Fowler)Pragmatic ProgrammerClean code[NEW] Software Engineering: A Practitioner's Approach[NEW] The Mythical Man-Month[NEW] The Art of Computer Programming


Applying UML and Patterns (GRASP patterns)C++ coding standards (Sutter, Alexandrescu)The C++ programming language (Stroustrup, Part IV)Object-oriented programming (Peter Coad)P…