What's UOW?

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What’s UOW?

“A Unit of Work keeps track of everything you do during a business transaction that can affect the database. When you’re done, it figures out everything that needs to be done to alter the database as a result of your work.” – Martin Fowler

SO Unit of Work Key Info:

UOW keeps track of changes
UOW maintenance change list
UOW commits all changes at once

EF Core DbContext naturally UOW is realized

Each DbContext instance has a ChangeTracker that tracks changes to the entity
When DbContext.SaveChanges is called, all changes are committed to the database in one go via the transaction

Implementing Repository pattern in domain-driven Design，By UOW UnitOfWorkInterceptor took over after ApplicationServervice methods performed DbContext. SaveChanges operation

The transaction is just a way to realize the unit of work. EFCore can implement UOW without using transactions.

What’s Ambient Transactions?

Common Transaction：

using (var context = new ApplicationDbContext())
{
    using (var transaction = context.Database.BeginTransaction())
    {
        var student1 = new Student();
        student1.Name = "Robert Fatou";
        context.Add(student1);
        context.SaveChanges();
        // The Id will have a valid value
        Console.WriteLine(student1.Id);
        // Let's revert the operation
        transaction.Rollback();
    }
}

Ambient Transaction：

An ambient transaction is one that works at the thread level. Thus, all operations that occur in that context will be part of the transaction.

static void Main(string[] args)
{
    using (var scope = new TransactionScope())
    {
        CreateStudent();
        CreateCourse();
        // Uncomment the following line if you want to
        // have the previous operations persisted in the Database
        //scope.Complete();
    }
}
 
private static void CreateCourse()
{
    using (var context = new ApplicationDbContext())
    {
        var course = new Course();
        course.Name = "Programming I";
        context.Add(course);
        context.SaveChanges();
    }
}
 
private static void CreateStudent()
{
    using (var context = new ApplicationDbContext())
    {
        var student1 = new Student();
        student1.Name = "Transaction Scope";
        context.Add(student1);
        context.SaveChanges();
    }
}