[MUSIC]. >> Hello again, friends. Welcome back to Entity
Framework Core for beginners. In previous videos, we've looked at using
Entity Framework Core exclusively with SQL Server. In this video, we're
going to look at using Entity Framework Core with
other database providers. The database provider is a layer in the EF Core
architecture that's responsible for the
communication between Entity Framework Core
and the database. It's a pluggable architecture, which means EF Core can
support all databases. The first database provider we're
going to look at is SQLite. SQLite is an open
source cross-platform embedded database technology. In SQLite, the entire database
is stored as a single file. It's a great choice when
you don't want to take a dependency on a server-based
database platform. I'm starting with a
console application pre-configured with
my new kit packages. I've already written
context and model classes. The code in program.cs adds some
records to the product's table. Using a different database
provider with EF Core is often as simple as using
a different NuGet package. To use the SQLite provider,
I'm going to install the Microsoft.EntityFrameworkCore.SQLite
package. I'll uninstall the SQL
Server package too. Then I'll go to the
on-configuring method in ContosoPizza context and configure the context with the
UseSQLite extension method. The connection string points
to the file to be created. Now, I'll create my
initial create migration. After that, I'll use the update database command to
run the migrations. The ContosoPizza DB
file was created. Before we run, since I'm
using Visual Studio, there's one other
thing I need to check. By default, Visual
Studio wants to start the app in a different directory
than the build directory. If it does that, my app
won't find the database. Let's add a start working directory element to the CS
proj so that doesn't happen. Now let's run the app.
It's done running. Let's see if we got
any data in our file. In Visual Studio, I'll right click and get the
path of the database file, which I'm going to use to open in an open source tool
called DB browser. As you can see, the product
data looks as we expected. Now, let's do that same exercise again, but this time,
let's use Postgres. The database provider
for Postgres is provided by the Postgres
developer community. I'll add the
Npgsql.EntityFrameworkCore.PostgreSQL package to the project and
delete the SQLite package. Now, I'll replace the call to the .UseSqLite method with
a call to use Npgsql. Let me paste in my
connection string. Now, I'll generate and
run new migrations. Let's run the app. The app started running. I'll switch over to the pqadmin
tool and query the database. As you can see, the
product table has data. The final database
provider I'm going to show you is for Azure Cosmos DB. Cosmos DB is a fully
managed no SQL database for modern app development. This means that instead
of working like a relational database
management system, it works with JSON documents. I've already created a
free Cosmos DB account configured to use the core API. I haven't added any
database containers yet. It's just an empty Cosmos account. I'll go to the Keys tab to
get my connection string, then I'll go back to Visual Studio. I'll add the
Microsoft.EntityFrameworkCore.Cosmos package to the project and
remove the Postgres package. This time, I'll call
the UseCosmos method. In addition to the
connection string, I must also specify a database name. Since Cosmos DB is
a no SQL database and there aren't any
database schemas to update, let's delete the migrations folder. Since there are no migrations
to create the initial database, let's call
context.Database.EnsureCreated in program.cs to make sure
the database gets created. Ensure Created can cause performance issues so avoid
using it in production. One other difference we
need to account for with Cosmos DB is the primary keys. The other databases we used support auto generating
a primary identifier. Since Cosmos DB doesn't do that, we need to handle it ourselves. I'll change the ID in the
product class to a string. I'll initialize it as a
globally unique identifier. Since this primary key is a
foreign key on order details, I'll change product ID in that class to be a string
as well and I'll assign it to NULL along with the NULL forgiving operator.
Let's run the app. Now that that's done, let's
go over to the Azure Portal where we can see the
data we just added. In this video, we looked
at how EF Core uses database providers to support a plethora of different
database technologies. We looked at just three of the possible database
providers you can use. Visit the entity framework
for documentation to see the full list of
supported database providers. In the next video, I'm going
to show you some tips to optimize performance in
your EF core applications. [MUSIC]
