public void AddOpti()
{
using (var cx = LastWins.CreateContext())
{
var opti = new OptiEntity();
opti.Id = Guid.NewGuid();
opti.Value = 0;
opti.RowVersion = Guid.NewGuid();
opti.Created = opti.Updated = DateTime.Now;
cx.Optis.Add(opti);
cx.SaveChanges();
}
}
public void AddOrUpdate()
{
var id = Guid.NewGuid();
var initialRowVersion = Guid.NewGuid();
var lastRowVersion = Guid.NewGuid();
// Create a new OptiContext.
// - Pass a factory method to create a new DbContext
var oc = new OptiContext <SqlDbContext, OptiEntity>(() => LastWins.CreateContext());
// defines the method to select an entity
oc.SelectFunc = (cx) =>
{
var i = cx.Optis.Find(id);
return(i);
};
// defines the method to add an entity, if select returns no entity
oc.AddAction = (cx) =>
{
var oe = new OptiEntity();
oe.Id = id;
oe.Value = 0;
oe.Created = oe.Updated = DateTime.Now;
oe.RowVersion = initialRowVersion;
cx.Optis.Add(oe);
cx.SaveChanges();
};
// defines the method to update the entity, if select returns a entity
oc.UpdateAction = (cx, oe) =>
{
// update the entity
lastRowVersion = Guid.NewGuid();
oe.Value++;
oe.Created = oe.Updated = DateTime.Now;
oe.RowVersion = lastRowVersion;
cx.SaveChanges();
};
// initial add opti entity
oc.Execute();
}
public void AddOptiWithUpdateConflictSolving()
{
var id = Guid.NewGuid();
var initialRowVersion = Guid.NewGuid();
var lastRowVersion = Guid.NewGuid();
var oc = CreateOptiContext();
var updateCounter = 0;
oc.SelectFunc = (cx) =>
{
var i = cx.Optis.Find(id);
return(i);
};
oc.AddAction = (cx) =>
{
var oe = new OptiEntity();
oe.Id = id;
oe.Value = 0;
oe.Created = oe.Updated = DateTime.Now;
oe.RowVersion = initialRowVersion;
cx.Optis.Add(oe);
cx.SaveChanges();
};
oc.UpdateAction = (cx, oe) =>
{
// test information
updateCounter++;
if (updateCounter == 2)
{
Assert.AreNotEqual(initialRowVersion, oe.RowVersion);
}
// update the entity
lastRowVersion = Guid.NewGuid();
oe.Value++;
oe.Created = oe.Updated = DateTime.Now;
oe.RowVersion = lastRowVersion;
cx.SaveChanges();
};
// initial add opti entity
oc.Execute();
// simulate Execute part 1 -> create context and select entity
var cx2 = oc.ContextFactory();
var entity = oc.SelectFunc(cx2);
// modify in the meantime in another dbcontext
ModifyOpti(id);
// simulate Execute part 2 -> TryUpdate the existing entity. Its here, but modified
oc.TryUpdate(cx2, entity);
// update must be called twice!
Assert.AreEqual(2, updateCounter);
// check if the last row version is stored in the database
using (var cx = LastWins.CreateContext())
{
var opti = cx.Optis.Find(id);
Assert.AreEqual(lastRowVersion, opti.RowVersion);
}
}