Most of my dev experience is based on Ruby on Rails. The framework supports having a DB schema in two formats:
RoR DSL
SQL for cases when DSL is not enough. For instance, having an initially deffered unique constraint in PostgreSQL.
If it's needed to set up a DB from scratch, for instance in CI, it's possible to run a CLI task that will use either of the files and apply it without any further need to run migration files.
About two weeks ago we started a project that based on ExpressJS + PrismaJS and now we need to have a custom SQL for the DB structure.
After reading the Prisma docs I found that it's possible to write a custom SQL inside migration files and this is exactly what we need for our production. However, we also would like to have the same DB schema in our CI. Is there any other way to have the same schema for CI as we have in production without running migration files one by one as I can do with RoR?
So I've added a relation to my SQLite database and now I want to update my entities in typeorm. Do I have to do this manually or is there a way with which I can generate those new entities. I used typeorm-model-generator for the initial generation of the entities...
I also tried using the generate migration command of typeorm but this turned out being used for updating the database according to the entities I would have written. (code-first)
For doing authorization in asp.net mvc 5 I have searched lot on internet but not getting correct answer. Actually I am using Visual studio community edition with .net framework 4.5.2 and mvc5. I want to do the Authorization in my project. My project is created with no authentication mode while creating a project.
Firstly I have tried these things:
I typed a command "Enable Migrations" on Package manager console.
Then I got one error like: Creating a DbModelBuilder or writing the EDMX from a DbContext created using Database First or Model First is not supported. EDMX can only be obtained from a Code First DbContext created without using an existing DbCompiledModel.
I dont know how to resolve this error. please help me to get out of it.
Which approach did you chooses to build our database model? Code First, Model First or Database First?
I'm asking because you can't use migrations with Model First or Database First approach. EF Migrations is a product targeted for Code First approach. CodeFirst assumes that you will never make any changes manually to the database. All the changes to the database will go through the code first migrations.
But there is solution for that - you can use Code First approach with an existing database. Take a look here: Using EF “Code First” with an Existing Database.
I am using MVC5 and EF6 CodeFirst migrations. My model is in a separate project from my MVC web app and I keep getting this error when trying to access the model classes. I have automatic migrations already enabled. I can drop the entire database and then using update-database to regenerate everything I still get this error. The error is wrong because the context has not changed since I created the database. Also, through a Unit Test project, using the same calling code as I have in my MVC app, I can reference the same Model project, access the model classes and data. I have the Model separate from the MVC project because I need to be able to reuse the Model outside of the web.
The model backing the "xx" context has changed since the database was created. Consider using Code First Migrations to update the database
Database.SetInitializer<DbContext>(null);
http://patrickdesjardins.com/blog/the-model-backing-the-context-has-changed-since-the-database-was-created-ef4-3
I got a similar problem :
The model backing the 'ApplicationDbContext' context has changed since
the database was created. Consider using Code First Migrations to
update the database
I have one project for MVC and another project for the model, context and repositories. I've been working on it for weeks but today it said stop.
I have tried to delete database, enable-migration, add-migration and update-database so many times that I've lost count. I've added initializers to MigrateDatabaseToLatestVersion as well as DropCreateDatabaseIfModelChanges.
What finally made it work was to move model, context and repositories into the MVC project (not something I was keen on)...then it worked right out of the box without any code changes at all (besides namespaces)! Very strange...
I've read so many blog posts during the day trying to solve this problem. One of them (I don't know which one) mentioned a bug in Visual Studio 2013 where reference to DLL files weren't always updated as they should, suggesting that my MVC project missed out something when I was running add-migration and update-database in my separate project. But it's just a guess.
I'm using EF 6.1 and .Net 4.5.1 in my solution.
Just to elaborate on RouR's answer:
I had an MVC web project that had a model attached.
I then created a console app that consumes this model.
My console app, only is aware of the connection string and has EF reference, just doesn't know how to let each one communicate.
Hence, the model backing database changed error appears
The engine is just confused how to proceed it sees and expects an entity, as was reference, just losses it when it fails to find the proper context, and assumes context wan't migrated properly.
So here we are,
Database.SetInitializer<MyProject.Models.MyModel>(null);
We are having the same issue. What solved it for me was not necessarily to move the Model, Context into the MVC project, but move my seperate project to the same solution as the MVC project and reference it by project folder.
This worked, but referencing a DLL instead of a project did not work.
Funnily enough, when creating a new Console Application and referencing the DLL assembly, we did not get this issue... only from an MVC project
We use EF code migrations to keep databases schemas up to date. The other day I had the same problem, in my case I was working with 2 database instances (QA and DEV databases of the same client with exact same data however QA environment was throwing this error. I've fixed the problem by deleting the _MigrationHistory folder and problem solved.
When I set up a connection for Subsonic 3.0.0.4 to connect to an Oledb sql provider using the T4 Templates I get the following error: Keyword not supported 'provider' Can Subsonic access a database using OleDb? If so. How?
Which dbms do you want to use?
Since SubSonic 3 uses System.Data.Common for accessing data, it should be possible to use it with every dbms that supports ADO.net (I belive there is a OleDbProvider for ado).
But if you use a DBMS that is not supported by subsonic you have write your own DataProvider and an OleDb.ttinclude template file.
The beste starting point is to look at an existing provider:
https://github.com/subsonic/SubSonic-3.0/tree/master/SubSonic.Core/DataProviders/MySQL
https://github.com/subsonic/SubSonic-3.0-Templates/tree/master/TemplateProviders
Creating your own Provider shouldn't be to hard at all. I would use a Copy&Paste approach from an existing provider and modify everything that causes some errors.
I would use the standard SQL to LINQ Entity spaces but I have to connect to a database for a client through their application server's specific OLEDB provider. Apparently it's doing extra work after the standard OLEDB SQL commands are sent to the server. So LINQ as far as I understand is out. I built my own CRUD classes, but it's a pain doing it this way. I just want a tool that can build the standard classed so I don't have to create the layer myself.
It's MS SQL Server 2005 on the other end.