ABP Framework is designed to be [modular](Module-Development-Basics.md), [microservice compatible](Microservice-Architecture.md) and [multi-tenancy](Multi-Tenancy.md) aware. Connection string management is also designed to support these scenarios;
> Connection string system is especially needed when you want to create or use a modular system. If you have a monolithic application with a single database, you can go with the [ABP startup solution template](Startup-Templates/Application.md), which is properly configured for you.
* Allows to set separate connection strings for every module, so every module can have its own physical database. Modules even might be configured to use different DBMSs.
ABP Framework is designed to be [modular](Module-Development-Basics.md) and [multi-tenancy](Multi-Tenancy.md) aware. Connection string management is also designed to support these scenarios;
* Allows to set separate connection strings for every module, so every module can have its own physical database. Modules even might be configured to use different database providers.
* Allows to set separate connection string and use a separate database per tenant (in a SaaS application).
It also supports hybrid scenarios;
* Allows to group modules into databases (all modules into a single shared database, 2 modules to database A, 3 modules to database B, 1 module to database C and rest of the modules to database D... etc.)
* Allows to group modules into databases (e.g., all modules into a single shared database or two modules to database A, three modules to database B, one module to database C and rest of the modules to database D)
* Allows to group tenants into databases, just like the modules.
* Allows to separate databases per tenant per module (which might be harder to maintain for you because of too many databases, but the ABP framework supports it).
* Allows to separate databases per tenant per module (which might be hard to maintain for you because of too many databases, but the ABP framework supports it).
All the [pre-built application modules](Modules/Index.md) are designed to be compatible these scenarios.
@ -29,15 +31,15 @@ See the following configuration:
This configuration defines three different connection strings:
* `MyMainDb` (the `Default` connection string) is the main connection string of the application. If you don't specify a connection string for a module, it fallbacks to the `Default` connection string. The [application startup template](Startup-Templates/Application.md) is configured to use a single connection string, so all the modules uses a single shared database.
* `MyIdsDb` is used by the [IdentityServer](Modules/IdentityServer.md) module.
* `MyPermissionDb` is used by the [Permission Management](Modules/Permission-Management.md) module.
* `MyMainDb` (the `Default` connection string) is the main connection string of the application. If you don't specify a connection string for a module, it fallbacks to the `Default` connection string. The [application startup template](Startup-Templates/Application.md) is configured to use a single connection string, so all the modules uses a single, shared database.
* `MyIdsDb`(the `AbpIdentityServer` connection string) is used by the [IdentityServer](Modules/IdentityServer.md) module.
* `MyPermissionDb`(the `AbpPermissionManagement` connection string) is used by the [Permission Management](Modules/Permission-Management.md) module.
[Pre-built application modules](Modules/Index.md) define constants for the connection string names. For example, the IdentityServer module defines a ` ConnectionStringName ` constant in the ` AbpIdentityServerDbProperties ` class (located in the ` Volo.Abp.IdentityServer ` namespace). Other modules similarly define constants, so you can investigate the connection string name.
[Pre-built application modules](Modules/Index.md) define constants for the connection string names. For example, the [IdentityServer module](Modules/IdentityServer.md) defines a ` ConnectionStringName ` constant in the ` AbpIdentityServerDbProperties ` class (located in the ` Volo.Abp.IdentityServer ` namespace). Other modules similarly define constants, so you can investigate the connection string name.
### AbpDbConnectionOptions
ABP actually uses the `AbpDbConnectionOptions` to get the connection strings. If you set the connection strings as explained above, `AbpDbConnectionOptions` is automatically filled. However, you can set or override the connection strings using [the options pattern](Options.md). You can configure the `AbpDbConnectionOptions` in the `ConfigureServices` method of your [module](Module-Development-Basics.md) as shown below:
ABP uses the `AbpDbConnectionOptions` to get the connection strings. If you configure the connection strings as explained above, `AbpDbConnectionOptions` is automatically filled. However, you can set or override the connection strings using [the options pattern](Options.md). You can configure the `AbpDbConnectionOptions` in the `ConfigureServices` method of your [module](Module-Development-Basics.md) as shown below:
````csharp
public override void ConfigureServices(ServiceConfigurationContext context)
@ -64,13 +66,11 @@ public class IdentityServerDbContext
For [Entity Framework Core](Entity-Framework-Core.md) and [MongoDB](MongoDB.md), write this to your `DbContext` class (and the interface if it has).
> If you are developing a reusable, database provider independent module see also [the best practices guide](Best-Practices/Index.md).
## Database Migrations for the Entity Framework Core
Relational databases require to create the database and the database schema (tables, views... etc.) before using it.
The startup template (with EF Core ORM) comes with a single database and a `.EntityFrameworkCore` project that contains related classes and the migration files for that database. This project mainly defines a *YourProjectName*DbContext that calls the `Configure...()` methods of the used modules, like `builder.ConfigurePermissionManagement()`.
The startup template (with EF Core ORM) comes with a single database and a `.EntityFrameworkCore` project that contains related classes and the migration files for that database. This project mainly defines a `YourProjectNameDbContext` class that calls the `Configure...()` methods of the used modules, like `builder.ConfigurePermissionManagement()`.
Once you want to separate a module's database, you typically will need to create a second migration path. See the [EF Core Migrations](Entity-Framework-Core-Migrations.md) document to learn how to create and use a different database for a desired module.
Halil İbrahim Kalkan
4 years ago