what is the best practice to use multiple database? #3234 | Support Center

fguo created 7 years ago

I am following "Developing-Step-By-Step-Angular" to add my own application. I want to keep all built-in functions in "default" database and store my own application data in a separated database.

I added another ConnectionString in appsettings.json, like { "ConnectionStrings":{"Default": "//default string", "AppData":"//application string"}, ......}

I wonder what is the best practice to use the separated connection "AppData". For example in "Creating Person Entity" step, how do I reference the connectionString to create [Table("PbPersons")] into "AppData" database?

Actually, the "AppData" database and tables exist already. I don't need to migrate/seed. I just need to map the schema from existing table to Person entity. Please advise!

Thanks,

14 Answer(s)

0

ismcagdas created 7 years ago
Support Team

Hi,

You can crate a second DbContext for your AppData and use new connection string for second DbContext. You can check this example <a class="postlink" href="https://github.com/aspnetboilerplate/aspnetboilerplate-samples/tree/master/MultipleDbContextDemo">https://github.com/aspnetboilerplate/as ... ontextDemo</a>.

If your DB already exists, after setting connection string, add migration and remove it's content for using it as a starting point, then you can use migrations for changes in your second dbContext.

If you don't want to use migrations for second db at all, you can disable it.

Thanks.
0

fguo created 7 years ago

Can I clone/download your example from git?

Thanks,
0

ismcagdas created 7 years ago
Support Team

Hi @fguo,

Yes, of course. This is an open source project.

Thanks.
0
fguo created 7 years ago
I cloned it to my local machine and studied it. It seems for “Boilerplate” users, instead of Prime users. To implement the same concept into ASP.NET Zero project, I tried the following steps, but it failed :( . Let me describe it step-by-step as following, and hope you can tell me what I missed.

In .Web.Host project, appsettings.json, add another ConnectionString: “App1” with same value of “Default”.

In .Core project, Costs.cs, add a const: public const string ConnectionStringName1 = "App1";

In .EntityFrameworkCore project, create a new folder: App1EntityFrameworkCore.

Copy all files in EntityFrameworkCore folder into App1EntityFrameworkCore folder, and replace the file name prefix with “App1”, so new files named as App1xxx.cs.

Set new namespace ProjecrtName.App1EntityFrameworkCore in all new copied files.

Change all “DbContext” words to “App1DbContext” in all new copied files.

Change ConnectionStringName to ConnectionStringName1 in App1DbContextFactory.cs.

Build and run successfully without compile error.

Then, I tried to connect an existing table “Customers” in another database with “App1” connectionString:

In .Core project, I added a file: App1\Customer\Customer.cs. It contains a class [Table("Customers")] public class Customer: FullAuditedEntity { [Required] [MaxLength(200)] public virtual string SCM_Name { get; set; } // It is an existing column name. }

In App1DbContext.cs file, I cleaned old code and added new code as below: public class App1DbContext : AbpZeroDbContext<Tenant, Role, User, App1DbContext> { public virtual DbSet<Customer> Customers { get; set; } public App1DbContext(DbContextOptions<App1DbContext> options) : base(options) { } }

I tried to add migration to see if this new table can be created (I am not going to update database). I run Add-Migration "Added_Customers_Table", but it prompts me “More than one DbContext was found.” So I run as Add-Migration "Added_Customers_Table" -Context "App1DbContext". It generated a class Added_Customers_Table, but it does not contain the creation of new table. Instead, it contains many tables, just same as “Initial_Migration” class. :?: :?: I think something wrong from this point.

I continue to add a service “GetCustomers” and it successfully added on Swagger as /api/services/app/CustomerService/GetCustomers. But, the Unit test failed, and if I directly run localhost:22742/api/services/app/CustomerService/GetCustomers, I got “internal error”: {"result":null,"targetUrl":null,"success":false,"error":{"code":0,"message":"An internal error occurred during your request!","details":null,"validationErrors":null},"unAuthorizedRequest":false,"__abp":true}

I lost here. Please advise how to implement “Multiple Database” in ASP.NET Zero project.

Thanks,
0
ismcagdas created 7 years ago
Support Team
Hi,

Can you try to add migration using configuration for your second dbContext ?

Add-Migration MYMIGRATION -ConfigurationTypeName ConfigurationB

Also be sure that both dbContexts have different configuration classes.

Thanks.
0

fguo created 7 years ago

Do you mean to use a parameter "-ConfigurationTypeName"? I used a command as:

Add-Migration "Added_Customers_Table" -Context "App1DbContext" -ConfigurationTypeName "App1DbContextConfigurer"

That is wrong. "A parameter cannot be found that matches parameter name 'ConfigurationTypeName'".

The above "App1DbContextConfigurer" is the class name for the new DbContext:

public static class App1DbContextConfigurer { public static void Configure(DbContextOptionsBuilder<App1DbContext> builder, string connectionString) { builder.UserSqlServer(connectionString); } }

Can you give me the exact Add-Migration command?
0
ismcagdas created 7 years ago
Support Team
Hi,

I was trying to suggest this:

Add-Migration "Added_Customers_Table" -ConfigurationTypeName "App1DbContextConfigurer"

If that does not work, please send your project to us and we will check it. You can send it to <a href="mailto:[email protected]">[email protected]</a>.

Thanks.
0
fguo created 7 years ago
I tried again by copy/paste your command in VS 2007 Package Manager Console, and got the error massage below:

PM> Add-Migration "Added_Customers_Table" -ConfigurationTypeName "App1DbContextConfigurer" Add-Migration : A parameter cannot be found that matches parameter name 'ConfigurationTypeName'. At line:1 char:39

Add-Migration "Added_Customers_Table" -ConfigurationTypeName "App1DbC ...

~~~~~~~~~~~~~~~~~~~~~~

CategoryInfo : InvalidArgument: (:) [Add-Migration], ParameterBindingException

FullyQualifiedErrorId : NamedParameterNotFound,Add-Migration

What did I miss?

By the way, how do I send you my project? Shall I zip all files in aspnet-core\src*.EntityFrameworkCore, and attach this zip file on email?

Thanks,
0

ismcagdas created 7 years ago
Support Team

Hi,

You can zip it and send it via google drive. You need to send all of your project not just EntityFramework.

Thanks.
0

fguo created 7 years ago

I have emailed a link to <a href="mailto:[email protected]">[email protected]</a>.

Thank you!
0

ismcagdas created 7 years ago
Support Team

Hi @fguo,

I have got your project but couldn't check it yet. We were very busy with v4.1 of AspNet Zero. I will get back to you in a short time.

Thanks.
0

ismcagdas created 7 years ago
Support Team

Hi @fguo,

I'm sharing your message in case anyone else faces same problem.

I have found the cause, which is the missing interface for the 2nd DB entities.

Thanks.
0

fguo created 7 years ago

I don't understand. Where does your quote come from?? What is the "interface for the 2nd DB entities"?
0

ismcagdas created 7 years ago
Support Team

Hi @fguo,

Sorry, It was another problem and I thought it was you but I was wrong. The problem was similar to your case.

Becase of that I didn't check your problem but I will take a look at it today.

Thanks.

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