Linq-to-Sql SubmitChanges 不更新字段......为什么?

问题描述

I posted this question yesterday evening, which has led me to discover a huge problem!

I have a decimal column in my database called Units, anytime I set the value of the column to a NON ZERO, and SubmitChanges the column updates with the new value. If I try to set the value of the column to ZERO, the SubmitChanges does not update the column.

data.Units = this.ReadProperty<decimal>(UnitsProperty);
data.UnitPrice = this.ReadProperty<decimal>(UnitPriceProperty);
data.Price = this.ReadProperty<decimal>(PriceProperty);

I've taken a look at the DataContext log and I can see that the field with the ZERO value is not included in the query. Even if I try to hard code the change Linq ignores it.

data.Units = 0;
data.UnitPrice = 0;
data.Price = 0;

Needless to say this is killing me! Any ideas why this happening?

Solution

I figured out my problem with the help of the SO community. My problem was being caused by the fact when I created my entity to attach, the default value of the column was set to zero, so when it tried to assign the value to zero ... LinqToSql says hey ... nothing changed, so I am not updating the value.

What I am doing now ... just to make it work is the following:

ctx.DataContext.InvoiceItems.Attach(data, true);

That seems to force all the values to write themselves to the database. This works for now.

I figured out my problem with the help of the SO community. My problem was being caused by the fact when I created my entity to attach, the default value of the column was set to zero, so when it tried to assign the value to zero ... LinqToSql says hey ... nothing changed, so I am not updating the value.

What I am doing now ... just to make it work is the following:

ctx.DataContext.InvoiceItems.Attach(data, true);

That seems to force all the values to write themselves to the database. This works for now.