Faactory.DbContext.SqlClient 0.3.0

ADO.NET Extensions

This project contains a set of extensions to help with managing multiple data sources, more specifically, inside a DI scenario.

Getting started

Before we can use the extensions, we need to register the context provider with our DI container. We'll have to install the appropriate package; the following providers are currently supported

We'll use SqlServer as an example

$ dotnet add package Faactory.DbContext.SqlClient

On our Startup.cs class, we'll register the provider and configure our databases; we can add multiple contexts.

IServiceCollection services = ...

services.AddSqlDbContextProvider()
    .AddDbContext( "my-db", "connection_string" )
    .AddDbContext( "my-other-db", "connection_string" );

Wherever we need to get access to our database context, we'll use the injected IDbContextFactory instance to retrieve an IDbContext instance.

public class Example
{
    private readonly IDbContext mydb;

    public Example( IDbContextFactory dbContextFactory )
    {
        mydb = dbContextFactory.GetDbContext( "my-db" );
    }

    ...
}

When we require a new connection, we'll use the IDbContext instance to construct a new connection.

public class Example
{
    private readonly IDbContext mydb;

    ...

    public async Task DoSomethingAsync()
    {
        using ( var connection = mydb.GetDbConnection() )
        {
            await connection.OpenAsync();

            ...
        }
    }
}

We can also construct the connection and open it directly

public async Task DoSomethingAsync()
{
    using ( var connection = await mydb.OpenAsync() )
    {
        ...
    }
}

From this point forward, we'll have an IDbConnection instance ready to use.

Note: All IDbConnection instances should be properly disposed after use. Most of the ADO implementations will pool connections and not properly disposing the connections can lead to exceeding the number of open connections.

Transactions

As an alternative to the IDbConnection.BeginTransaction method, there are extensions available to shorten the syntax. The UseTransaction[Async] methods take care of opening/reusing a connection, creating a transaction and gracefully disposing of it all when finished.

public async Task DoSomethingAsync()
{
    await mydb.UseTransactionAsync( async t =>
    {
        var sqlCommand = t.Connection.CreateCommand();

        ...

        await t.CommitAsync();
    } );
}

If an error occurs, the transaction is automatically rolled back. We can also provide additional behaviour to when this happens.

public async Task DoSomethingAsync()
{
    await mydb.UseTransactionAsync( async t =>
    {
        var sqlCommand = t.Connection.CreateCommand();

        ...

        await t.CommitAsync();
    }, ex =>
    {
        // handle exception
    } );
}