I have the main website that uses a database to store and access user accounts. I'm using EF to manage the schema. I also defined site-specific POCOs and have migrated them to the database.
Now, what if I want a separate website, for example, a resource server (Web API) that would expose (with authorization) the same data set up on the main website?
Do I create the same POCOs and derived DbContext on the resource server again? That seems like duplicating work, though.
What if I wanted to create new POCOs on the resource server and reflect them onto that same database? Wouldn't that conflict with the current migration (which is saved on the database), then subsequently mess up the EF setup on the main website?
I've seen the suggestion of putting the POCOs and DbContexts in a library and have multiple projects reference that same library. This seems viable, however I'd have to hard-code the connection string, which seems dirty to me.
I'm starting to think that EF is probably not recommended for this kind of setup. It seems like a database-first approach plays better here - though I would have to manually reedit the data contexts (most likely, LINQ-SQL) for every database schema change.
Are there any lesser-known capabilities, facts, practices, etc., for/about EF that would help in this situation?
Generally, you can avoid duplication by having one API serving both sites and have resources version for each if needed. On the other hand, if you choose reuse and add approach, creating additional EF code-first entities should not interfere with other site data layer if modeled and mapped carefully. DbContext connection string does not have to be hard-coded.
Related
I am switching over to Symfony for a project that I am working on but I need a little advice on how to structure the files when it comes to models and using doctrine.
I have a custom framework that I use, which in turns uses the MVC model. Pretty much all of my MYSQL database queries are stored in the models and I access them through the controller.
Now after looking at Symfony2, my interpretation is that "model" files in Symfony are called Servies. Is this correct?
I have also generated a number of Entities that correspond to my MYSQL database. My question here is do I place my custom Doctrine queries inside the Service files or do I create them inside the Entity files?
I'm a little unsure how to structure this.
Thanks
Pretty much all of my MYSQL database queries are stored in the models
That's bad, but I'll mention about it later.
Now after looking at Symfony2, my interpretation is that "model" files in Symfony are called Servies. Is this correct?
Queries should be done in either repositories or in some cases in services.
If your query returns entities, then it should be repository for sure.
My question here is do I place my custom Doctrine queries inside the Service files or do I create them inside the Entity files?
Entities should be plain PHP objects. They shouldn't depend on anything than other entities. Entities actually doesn't even know anything about database. It's pure object oriented business logic.
Again, all DB queries should be in repositories or services.
I would suggest to go through Symfony Book in first place, to get idea of how "the Symfony way" works.
Symfony is not MVC framework:
Symfony2 is really about providing the tools for the Controller part, the View part, but not the Model part [...] Symfony2 is an HTTP framework; it is a Request/Response framework.
And it is great. Symfony allows to make your model as you wish without any restrictions. The Doctrine (ORM and/or DBAL) is a separate set of libraries. You can use any other library, or build your own persistence layer abstraction, or work with native SQL through PDO/MySQLi/etc.
Service is just an object that registered in the container and have some dependencies. Services can doing anything. They can represent your model, but it is not a requirement.
Organizing Your Business Logic (The Symfony Best Practices)
Doctrine ORM Best Practices
I am working on an application where the ui may connect to multiple databases. Some of these databases have static schema. Others need to be queried based on schema provided by the admin (dynamically).
I want to be able to use the features of Entity Framework when working on the static databases and somehow use ADO.Net for the dynamic databases.
Also there is a possibility that a static db has 90% expected schema but few tables are generated dynamically. So I want Entity Framework to just work with the models I have defined. I dont want it to crib about the dynamic tables which got generated.
Is there a way ? Am I making sense ?
Try to refer this link and its too complex to map EF runtime so its better to go with ado on dynamic things and try to put static things in EF.
I have just started working on entity framework in an ASP.net application and I was wondering if someone could point in the right direction with respect to best practices. I have some questions in particular which I have listed below.
First of all I am using entity framework 4.0. I already have my database created and so I created a class library and generated the entity model from the database. I had been using Guids generated by the database so I had to modify the ssl to include the attribute StoreGeneratedPattern="Identity". Is there a way to do this automatically or do I have to manually edit the ssl everytime I update the database and the model? (For those of you know are facing a problem with guids or want to know why I am doing this.. this is a clear article on the problem with auto generated GUIDs)
I was planning on using a single file in the class library to hold all the database queries. Is this good practice? How would I ensure different programmers dont rewrite the same queries over and over?
I was planning on using a unique context per method. Is this the right way to go? I read through Rick Strahl's post on context lifetime management. But I am still not sure if a unique context per method is the right way to go.
Can I have my database queries as static methods since they do not make use of any instance variables?
If I use a unique context per method as mentioned in 3 and I wish to modify an entity object returned by one context what would be the best practice? Do I use the attach functionality to attach the object to a new context and save the changes ? I havent tried this but I have read a couple of articles and it seems a bit straightforward but wanted to know if there are any alternatives to this.
If you any suggestions on how you use Entity Framework in an ASP.net application I definitely could use help. This is my first ASP.net/Entity framework application so any tips will help
This was issue in initial version of VS 2010. In some cases this should already work correctly once you have VS 2010 SP1 installed. If it doesn't install this KB.
You can easily get huge class with a lot of static methods. Try to use some separation by the entity type you are querying. You will never fully ensure that another programmer will not create the same query again. This is about correct query naming following same naming policy, documentation and communication among programmers.
Unique context "per method" is usually not needed. In most cases you should be happy with unique context per logical (business) transaction - in case of web application logical operation is in most cases single request processing = one context per request.
If you pass context instance to your queries the answer is yes. Once you don't create them as static and they will take context instance from their class instance you will be very close to repository pattern.
This is exactly problem with context per method and it is hard to solve because to make this work you must first detach entity from the first context and attach it to the second context. If your entity has also related entities loaded all these relations will be nulled during detaching (unless you use deep clone instead of detaching = creating second instance of the entity).
I currently have an ASP .NET MVC / EF4 project that contains many pieces of autonomous functionality such as a blogging, events, contests, wiki, etc.
The entities used by each system are all mapped to my database through one giant EDM file.
This works well for the main site, but I also have a few personal sites where I want to reuse just the blogging functionality from the mains ite.
My biggest problem is that due to the mac daddy EDM file, my blog sites have to constantly have their database schemas updated to reflect changes made to areas of functionality that they don't use (i.e. changes to the events system).
The only other gotcha is that there are some entities (Users and Tags) that have relationships with entities from each area of functionality, making it hard to simply split each area of functionality off into its own EDM.
With all of this said, I'm trying to figure out the most efficient way to set this up.
Should I go down the road of splitting up the EDMs by each area (blogs, events, contests, wiki) and figuring out a way to maintain relationships for the User and Tag entities?
Or should I just perhaps be creating an EDM for each website that only maps the entities that it will actually need? The only problem with this is that my repository layer takes in a UnitOfWork/ObjectContext, and by creating new ObjectContexts for each site I'd have problems reusing my repository code.
You could setup a WCF service and then pass your data via a JSON contract. That way you'd have a central service that holds your EF data, and then just exposes functions based on what the your different applications need.
Its more short term work to setup (hopefully your service/repository layer was done with IoC in mind to allow it to be easily plugged in) but if your EF data changes a lot, it means you can update the one central service without having to update each of your clients apps.
There's a good reference thread here on S.O: https://stackoverflow.com/questions/973017/where-to-find-good-wcf-video-tutorials
How can we extend the Alfresco database? I need to add new tables to the existing database structure.
Does alfresco support this?
thanks in advance,
sri..
I think changing the alfresco db model is never a good solution. Some alfresco upgrades are made using Schema Upgrade Scripts, and that could get messy.
Have you tried to extend the alfresco content model?
Alfresco support some data types, allowing you to persist data. The Web Script framework allow you manipulate all your data inside your content model.
If your data is not suitable for a "content model", I think you should create a new database to hold your data.
Well, it is just a database. So you can create as many new tables as you want just like you would in any other database.
Obviously Alfresco won't use them because it doesn't know them, but you can query the tables as you like.
Advices from alfresco engineers are do not touch alfresco database. Please take a look at this page.
http://forums.alfresco.com/forum/general/non-technical-alfresco-discussion/where-alfreso-user-details-are-stored-i-alfresco
Changing alfresco database is not recommended.Content Model will be the good way.If such requirement is mandatory than,
You can use spring with hibernate for database connection.Properties which is required for connecting database are all ready declared inside alfresco-global.properties which is located inside "tomcat/shared/classes/".
For Spring bean injection you can declare beans inside any file which ends with "-context" which resides inside "tomcat/shared/classes/alfresco/extension" folder.
I will still recommend developer to use content model.
Depending on your use case, you may or may not need to play directly with the[/a] data base. I think your use case should fall in one of the following:
Use case 1:
You need to setup some metadata on folders and/or documents. You may have to nest multiple levels of nodes with different sets of custom metadata on each level.
You probably need to extend alfresco models in order to define custom document/folder models that best suits your business requirements. Please check jpotts' tutorial to learn how to do so.
Use case 2:
You need to define multiple lists with different sets of properties, those lists may or may not be linked to some content in your alfresco repo.
You probably need to learn more about alfresco sites' datalists, once you do so you may be interested in learning how to extend OOTB alfresco content model, jpotts' tutorial would be a good starting point, and then you should be checking this tutorial in order to learn how to manage datalists in stand alone aikau apps/share pages.
Use case 3:
You need to leverage a relational database in order to define and leverage you complex business logic that do not fall in any of the use cases defined above.
Are you sure you do not want to code a brand new app leveraging a technology that you are familiar with and have it communicate with alfresco using RESTfull api/cmis/.... ?
Are you sure alfresco is THE way to go ? If so, and you still want to have your custom complex business model in a bare relational database:
Please consider using a separate database instance / database for your custom extension, this way you would be sure any new patch/upgrade to alfresco that may change database structure won't affect your extension (or at least wont give you hard time upgrading it)
If you are really tied to only 1 database instance / 1 database schema, you will probably want to precede your table names with some prefix and hope none of alfresco future upgrades would have new tables with the same prefix. You probably also need to make sure to manage your database config wisely (connection pools ..) so neither your alfresco instance nor your custom extension have to starve. (make sure you close the connections you are opening)
Alfresco and Activiti come with a database. It is not good to access the database directly. Doing so can cause unexpected locking behavior or exhaust connection pools on the DB. This turns out into performance problems and other kinds of issues are possible too. In case you want to update Alfresco or Activiti you can do it through APIs. Easy to extend, easy to customize and hassle free integration capability are some of the reasons which has made http://loganwinson.doodlekit.com/blog/entry/4249216/top-things-to-know-about-alfresco-development>Alfresco web development popular among businesses.