After many fruitless searches I have decided to put my head above the parapet. I am building an EF6 code first application for an embedded device.
I have successfully followed many references to enable me to create SQL CE files in the folder locations I need.
However, I need to have two separate models running at the same time
1 - Admin model deals with common things like user logins and generic details.
2 - Project specific model where the real work gets done.
The concept is that the Admin database file resides and remains on the
device, but the project database file can be passed from one device to
another.
Is it possible to have two different model databases open at the same time in EF6?
If so is there a good reference site that my search terms have not yet found that will offer advice appropriate to my use-case?
Thanks folks.
I have been able to solve my own question now having found a new article to refer to Multiple Model EF 6 Data points
Read the article on how to solve my question and other variants of similar problems. The key to solving this problem was to specify separate folders for each context migration when commanding the NuGet Package Manager Console. Then in the initialiser for each context, refer to the configuration in the appropriate migration folder. Rather than repeating here, please see the article on MSDN I linked to as all the information I needed was in there, plus lots more.
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I'm new to flutter/dart and I'm trying to create a little application using a Clean Architecture design.
I read some blogs and several presentations of Uncle Bob's Clean Architecture before starting to code to get the most of it and now it's time to implement it.
I guess my application could be divided in 3 main features :
authentication
classes (get access to lessons/quizzes on specific subjects)
admin (manage user, create lessons etc..)
I started to implement the authentication feature following the clean pattern, that's to say with a domain, data and presentation layer and I guess I did it quite well. It's (almost) fully tested (I'm trying to do some TDD) and seems to work as I wanted.
Now comes the problem. I want to implement the classes feature. I wish it could be independent of the authentication but it's not the case... The classes feature need to get the authenticated user from the authentication feature. I searched a lot on the internet but I can't find how to implement Clean Architecture with multiple features that need to share some data.
So there are my 2 questions:
How to pass data from a feature to another ?
How to inject dependency in a feature that need data from another feature ? (I used get_it for the authentication feature and inject all dependencies in the main() method before building the app. Since it did not need any external data it worked well. Now it's seem not possible to do the same for the classes feature since it first needs to get some data from the authentication feature).
Thanks in advance for your answers.
Along with your 3 features you should add another called core and inside that folder you can add stuffs that need to be shared. It worked for me . Good luck
One option is if you instantiate classes after the user has already logged in, you can pass that data in as a constructor parameter.
More generally, Provider is probably the best dependency injection tool for flutter. If you "provide" the authentication class to the widget tree for the rest of the app, you can say at any point below it, Provider.of(context) to access it and any public field it has.
Hope you're still working on Flutter projects after that long time.
I've been fiddling around with Uncle Bob's Clean architecture, and I managed to implement it in Flutter few months ago.
It's perfect, it separates your code into components (modules if you're coming from a native Android development environment) and isolates your data sources, so if you want to change the way you make API requests for example, you'll only need to change the remote data source part in your app, and all your application should work as expected.
I have made a test app using Clean Architecture I just uploaded on github and added a humble readme that describes the basic architecture and components of the app, I'll work on written articles describing the code very soon.
For now you can access the repo from here
I'm trying to find an answer to this for some time now... My solution was to create some transformation methods in the model class. For example, I have an ProductModel in the home feature file (from where i can add products to the cart), and an ProductInOrderHistoryModel in the order history feature file. So in the ProductInOrderHistoryModel file I have a method called toProductModel that gets an instance of ProductInOrderHistoryModel and transform to a ProductModel. That way I can add a product to the cart directly from my history order page.
Probably it's not the best solution, and the Uncle Bom would be really mad at me. But it was how I manage to solve my problem...
I have read multiple posts about this but do not have a clear answer yet.
We are transitioning to EF Core 2.0 company-wide, one project at a time.
The challenge is this:
A new project starts and a database is created using code first, migrations etc.
another programmer needs to create a project targeting the same database.
This programmer can use Scaffold-DbContext and generate current models.
However, a new column is needed and this second programmer adds it.
Now...how do we best update the other projects?
Is there something that checks and syncs or shows what is out of sync between your model and a database? Meaning check the database for changes...not the model.
We don't mind buying a tool if that is the best solution.
The solution we have been using, very successfully is the Database project in Visual Studio.
Using that each developer has the project in their solution, changes are made against it locally.
Then we can do a "Schema Compare" inside of VS.
We have been using this successfully for 4 of us the past three weeks extensively with almost no issues.
This has even worked for keeping versions and changes to our stored procedures current.
It works well with VSTS also.
Here are some of the posts I read that helped me understand it:
https://www.sqlchick.com/entries/2016/1/10/why-you-should-use-a-ssdt-database-project-for-your-data-warehouse
https://weblogs.asp.net/gunnarpeipman/using-visual-studio-database-projects-in-real-life
..and this forum had a lot of relevant questions/answers:
https://social.msdn.microsoft.com/Forums/sqlserver/en-us/home?forum=ssdt
I'm developing an ecommerce based on Websphere Commerce 7 WCS7. I need to import products from an external supplier, which is exposing a webservice. I've already implemented a Controller Command performing all the operation needed to extract the products from the remote service, and I've them avalaible as custom Java classes.
I'm a little bit confused about the approach I should follow in this case. I've defined the attributes needed in my scenario and used the dataload utility to import them in the DB. What should I do next? I expect to be able to "create" WCS product programmatically from my Controller Command but I don't know how to use the attribute I've defined in a programmatic insert.
Can someone point me on the right track on how to perform this kind of operation? I went through the documentation, but, given the fact I'm quite new of the WCS environment, I don't know how to proceed according to the current best practices.
It is possible to create a new catalog entry programmatically if you copy what is being done in the LOBTools. I have not done this myself though. I have always added new products via the data loads and when we did need to add from an external service I just output the information to a file and loaded along with our other products. The reason was due to keeping the catalog in sync with the product management system.
Have a look at the various DataBean classes in WCS, like: CatalogEntryDataBean.
See here for WCS data beans:Link
And here for "activation" of a DataBean:Link
I'm using Entity Framework 5 model first. Say I've deployed the application and I'd like to upgrade an EF entity with new columns, basically adding columns to the table.
What is the best way to upgrade the existing database without losing data? For example I have a User table that I add two new columns to. If I try to script a schema change the tables will need to be dropped in order to add the new columns. Is there a way to update the tables without needing to recreate them? Thanks!
This may be a late answer but I have had the same problem and could just find one solution, there is an application that can update the model-first generated databases without losing the data.
It can directly open the model file and update the database tables.
It also installs some extensions on Visual Studio that I have not personally used but may be usable.
The name is Entity Developer and there are some editions of the application listed here:
Entity Developer Editions
The free edition is usable only for 10 entities or less that may not suit your needs but the Professional edition is usable for 30 day as a trial that may help you do the job. The only solution I could find on the net was this one.
Hope it helps you with the problem.
I'm new to MEF. In Managed Exensibility Framework, what do you mean by events exportschanging and exportschanged. How one can visualize it?
In the Managed Extensibility Framework, objects are wired together by matching imports with exports. I assume you already know about that. (If not, you should read through the MEF programming guide first and play with MEF a bit.)
In a typical scenario, exports are provided by a catalog of types. Some of these catalogs can be changed while the application is running, at which point the application might be recomposed.
Here are two examples of modifying a catalog:
DirectoryCatalog.Refresh() (this will rescan the directory and pick up new assemblies)
AggregateCatalog.Catalogs.Add
When this happens, the CatalogExportProvider based on the catalog will trigger the ExportsChanging event right before handling the change, and ExportsChanged right after.
Not all export providers have to be based on catalogs, but I hope you get the idea.