public async Task <int> CreateProductAsync(Product entity)
{
// Set default values
entity.Likes = 0;
entity.Stocks = 0;
entity.Available = true;
DbContext.AddEntity(entity);
return(await DbContext.SaveChangesAsync());
}
/// <summary>
/// Reconciles the stored entity graph extending as far as described by the given extent with the one given by entity.
/// It makes a number of load requests from the store, but all modifications are merely scheduled in the context.
/// This overload takes a prefetched attached entity that can allow the skipping of the load request in case of a
/// trivial extent.
/// </summary>
/// <param name="db">The context.</param>
/// <param name="attachedEntity">The prefetched graph to reconcile.</param>
/// <param name="templateEntity">The detached graph to reconcile with.</param>
/// <param name="extent">The extent of the subgraph to reconcile.</param>
/// <returns>The attached entity.</returns>
internal static async Task <E> ReconcileAsync <E>(this DbContext db, E attachedEntity, E templateEntity, Action <ExtentBuilder <E> > extent)
where E : class
{
// FIXME: We want to be able to deal with unset foreign keys, perhaps this helps:
// https://stackoverflow.com/questions/4384081/read-foreign-key-metadata-programatically-with-entity-framework-4
var builder = new ExtentBuilder <E>();
extent?.Invoke(builder);
if (attachedEntity == null || builder.reconcilers.Count != 0)
{
// In case of removals, the templateEntity is null, and otherwise
// attachedEntity is often null as it's not always preloaded by
// the caller.
var entityToTakeTheKeyFrom = templateEntity ?? attachedEntity;
attachedEntity = builder.reconcilers
.Aggregate(db.GetEntity(entityToTakeTheKeyFrom), (q, r) => r.AugmentInclude(q))
.FirstOrDefault();
}
var isNewEntity = attachedEntity == null || (db.Entry(attachedEntity).State == EntityState.Deleted && templateEntity != null);
if (isNewEntity)
{
attachedEntity = db.AddEntity(templateEntity);
}
foreach (var reconciler in builder.reconcilers)
{
await reconciler.ReconcileAsync(db, attachedEntity, templateEntity);
}
if (!isNewEntity && templateEntity != null)
{
db.UpdateEntity(attachedEntity, templateEntity);
}
foreach (var property in builder.properties)
{
property.Modify(db, attachedEntity, templateEntity);
}
return(attachedEntity);
}
public async Task PlaceOrderAsync(OrderHeader header, IEnumerable <OrderDetail> details)
{
using (var txn = await DbContext.Database.BeginTransactionAsync())
{
try
{
// Set default values for order header
header.OrderDate = DateTime.Now;
header.Total = 0m;
header.Total = details.Sum(item => item.Total);
DbContext.AddEntity(header);
await DbContext.SaveChangesAsync();
foreach (var item in details)
{
item.OrderHeaderID = header.OrderHeaderID;
DbContext.AddEntity(item);
}
await DbContext.SaveChangesAsync();
foreach (var detail in details)
{
var product = await DbContext
.GetProductAsync(new Product(detail.ProductID));
// Update stocks for product
product.Stocks -= 1;
}
await DbContext.SaveChangesAsync();
txn.Commit();
}
catch (Exception ex)
{
txn.Rollback();
throw ex;
}
}
}
public async Task <int> LikeProductAsync(Product entity)
{
var productLike = await DbContext
.GetProductLikeByProductIDAndCreationUserAsync(entity.ProductID, entity.LastUpdateUser);
if (productLike == null)
{
DbContext.AddEntity(new ProductLike
{
ProductID = entity.ProductID,
CreationUser = entity.LastUpdateUser
});
entity.Likes += 1;
DbContext.UpdateEntity(entity);
return(await DbContext.SaveChangesAsync());
}
return(0);
}
public async Task <int> UpdateProductPriceAsync(Product entity)
{
using (var txn = await DbContext.Database.BeginTransactionAsync())
{
try
{
// Set changes
entity.Price = entity.Price;
DbContext.UpdateEntity(entity);
await DbContext.SaveChangesAsync();
// Add product price to history
DbContext.AddEntity(new ProductPriceHistory
{
ProductID = entity.ProductID,
Price = entity.Price,
StartDate = DateTime.Now,
CreationUser = entity.LastUpdateUser
});
var affectedRows = await DbContext.SaveChangesAsync();
txn.Commit();
return(affectedRows);
}
catch (Exception ex)
{
txn.Rollback();
throw ex;
}
}
}