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Rethinkdb .net update value

I'm looking at updating stored values in a RethinkDB using the C# RethinkDB.Driver library and I'm just not getting it right.
I can achieve an update by getting the result, altering that object then making a separate call to update with that object. When there are many calls to a record to update like this, the value being updated elsewhere whilst the application is working with the record.
TestingObject record = r.Db("test").Table("learning").Get("c8c54346-e35f-4025-8641-7117f12ebc5b").Run(_conn);
record.fieldNameIntValue = record.fieldNameIntValue + 1;
var result = r.Db("test").Table("learning").Get("c8c54346-e35f-4025-8641-7117f12ebc5b").Update(record).Run(_conn);
I've been trying something along these lines :
var result = r.Db("test").Table("learning").Get("c8c54346-e35f-4025-8641-7117f12ebc5b").Update(row => row["fieldNameIntValue"].Add(1)).Run(_conn);
but the result errors with Inserted value must be an OBJECT (got NUMBER):101 which suggests this is only passing the field value back instead of updating the object.
Ideally I'd like to update multiple columns at once, any advice is appreciated :)

This is an example that works in the ReQL data explorer. You can chain as may filters before the update as you want. I assume this will translate to the C# Driver, but I dont have any experience with that.
r.db('database').table('tablename').update({clicks: r.row("clicks").add(1)}).run().then(function(result){ ...

Thanks T Resudek your answer and a clearer head helped emphasised the need to map the calculation to the property.
Looking at the javadocs for update it has HashMap method which I followed with the c# library and it works.
var result = r.Db("test").Table("learning").Get("c8c54346-e35f-4025-8641-7117f12ebc5b").Update(row => r.HashMap("fieldNameIntValue",row["fieldNameIntValue"].Add(1))).Run(_conn);
I'd be interested to know if this is the right way or was a better way.

System.Data.Linq.ChangeConflictException? Row not found or changed? But, I'm inserting, not updating

My program is writing records to a db table. So far, it has written about 58 new records to this table. All of a sudden, I get an error message saying "Row not found or changed." Which is odd, because I'm inserting a new record, not trying to find one or update an existing one. Here's the small bit of code that I'm using to create an object and then insert to the table:
// create new comment object
var comment = new Comment
{
TableName = "Circuit",
TableKey = circuitId,
Text = remarks,
CreatedOn = DateTime.Now,
CreatedByName = "loadCC03Circuits",
CreatedByUupic = "000000000"
};
cimsContext.Comments.InsertOnSubmit(comment);
cimsContext.SubmitChanges();
I'm not quite sure what to do, at this point. Each field has a value, there are no nulls. And, as I said, 58 records have already been written out by this very same bit of code before this happens so, other than the data being off (which, according to the field values in my debugger session, are not) I'm not quite sure what else to check. Any advice?
EDIT: I added an answer below that made this problem go away. But, I'm not sure why this solution worked.

I found a solution, but not the "answer". The solution, in this case, was to make a variable that contained the DateTime.Now value:
var dateNow = DateTime.Now;
And I changed the affected line of code to look like this:
CreatedOn = dateNow,
Wonders of wonders, I no longer received the error. I'm not sure why this fixed the problem, I only tried this on a suggestion from a co-worker. He theorizes that the sandbox database that I'm working is sluggish and could be affecting the DateTime.Now function. Regardless, this made that issue go away. I wish I had a definitive answer, though. I hate making a problem go away when I don't understand why the solution worked.

How to get Indentity value back after insert

Given the following code (which is mostly irrelevant except for the last two lines), what would your method be to get the value of the identity field for the new record that was just created? Would you make a second call to the database to retrieve it based on the primary key of the object (which could be problematic if there's not one), or based on the last inserted record (which could be problematic with multithreaded apps) or is there maybe a more clever way to get the new value back at the same time you are making the insert?
Seems like there should be a way to get an Identity back based on the insert operation that was just made rather than having to query for it based on other means.
public void Insert(O obj)
{
var sqlCmd = new SqlCommand() { Connection = con.Conn };
var sqlParams = new SqlParameters(sqlCmd.Parameters, obj);
var props = obj.Properties.Where(o => !o.IsIdentity);
InsertQuery qry = new InsertQuery(this.TableAlias);
qry.FieldValuePairs = props.Select(o => new SqlValuePair(o.Alias, sqlParams.Add(o))).ToList();
sqlCmd.CommandText = qry.ToString();
sqlCmd.ExecuteNonQuery();
}
EDIT: While this question isn't a duplicate in the strictest manner, it's almost identical to this one which has some really good answers: Best way to get identity of inserted row?

It strongly depends on your database server. For example for Microsoft SQL Server you can get the value of the ##IDENTITY variable, that contains the last identity value assigned.
To prevent race conditions you must keep the insert query and the variable read inside a transaction.
Another solution could be to create a stored procedure for every type of insert you have to do and make it return the identity value and accept the insert arguments.
Otherwise, inside a transaction you can implement whatever ID assignment logic you want and be preserved from concurrency problems.

Afaik there is not finished way.
I solved by using client generated ids (guid) so that my method generated the id and returns it to the caller.
Perhaps you can analyse some SqlServer systables in order to see what has last changed. But you would get concurrency issues (What if someone else inserts a very similar record).
So I would recommend a strategy change and generate the id's on the clients

You can take a look at : this link.
I may add that to avoid the fact that multiple rows can exist, you can use "Transactions", make the Insert and the select methods in the same transaction.
Good luck.

The proper approach is to learn sql.
You can do a SQL command followed by a SELECT in one run, so you can go in and return the assigned identity.
See

linq to sql submit changes not working

I have a list view with two colums in wpf Customername and Isvalid.I am using linq to sql to get the data from my sql table.when i am trying to update a value to the table i dont see any changes to the table.
Here is my code when i click on the save button:
try
{
CustomersDataContext dataContext = new CustomersDataContext();
Customer customerRow = MyDataGrid.SelectedItem as Customer;
string m = customerRow.CustomerName;
Customer customer = (from p in dataContext.Customers
where p.CustomerName == customerRow.CustomerName
select p).Single();
customer.Isvalid=false;
dataContext.SubmitChanges();
MessageBox.Show("Row Updated Successfully.");
}
catch (Exception Ex)
{
MessageBox.Show(Ex.Message);
return;
}
I can see that i am able to query the record based on the customername selected but the value is not updating.
I would be glad if some one can point out where am i missing the logic to update the "ISVALID" value to the data base.

Firstly, where's your using(get_datacontext){...} block? You need to dispose of DataContexts when you are done with them!
Anyway...
My guess is that the update statement is generating a where clause that's far too tight, or just plain wrong.
I would be checking the 'Update Check' property of each of the columns in your mapped table in the Linq to Sql designer. The simplest thing to do is to set the primary key column to Always and set all the others to Never. You can also consider setting them to WhenChanged.
The designer's default behaviour is generally to set it to Always for everything; not only does this cause horrible WHERE clauses for updates, but can occasionally also cause problems. Obviously such behaviour is required for proper concurrency checking (i.e. two threads updating the same row); so be aware of that.
Oh, thinking of something else - you can also get this behaviour if your table doesn't have a primary key designated in the designer - make sure one of the columns is.
Finally you can check the SQL being generated when SubmitChanges is called; by attaching a TextWriter to the DataContext.Log property; or equally IntelliTrace in VS2010 will collect all ADO.Net queries that are run if you start with debugging. This is invaluable in debugging why L2S stuff isn't working as expected.

You should Add updated Customer to list of updating customers. I mean before saving changes you should do something like: db.AddToCustomers(customer). AddToCustomers in used in EF, I exactly don't know its equivalent in LINQ.

Linq-to-Sql SubmitChanges not updating fields ... why?

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 have tried to reproduce this with a the following code, but for me it works.
using (DataClasses1DataContext ctx = new DataClasses1DataContext())
{
var obj = ctx.DecimalColumnTables.First();
Debug.Assert(obj.B != 0);
obj.B = 0;
ctx.SubmitChanges();
}
So I think there must be something special in your domain that causes this. I suggest you to create a such simple repro with your domain model and see what happens.
LINQ to SQL ignores updates to the current value, so if the field was already zero, you may not see any updates.
Off: The OR/M you use is LINQ to SQL. LINQ is the name of the querying capability in .NET, but LINQ does not define nor implement any update logic. So the issue relates to LINQ to SQL, not LINQ.

Obvious question, but are you sure the column is mapped in the dbml / mapping file?
Also - is it a calculated column? (i.e. price => units * unitprice)

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.

Some more information ... I figured out my problem ... it's more of a lack of understanding about LinqToSql ... where I am doing:
private void Child_Update(Invoice parent)
{
using (var ctx = Csla.Data.ContextManager
.GetManager(Database.ApplicationConnection, false))
{
var data = new Gimli.Data.InvoiceItem()
{
InvoiceItemId = ReadProperty(InvoiceItemIdProperty)
};
ctx.DataContext.InvoiceItems.Attach(data);
if (this.IsSelfDirty)
{
// Update properties
}
}
}
I thought this would load the original values ... what happens is that it creates a new object with default values ... empty values, like 0 for decimals, Guid.Empty for uniqueidentifiers and so on.
So when it updates the properties it sees the Units already as 0 and it sets it to zero. Well LinqToSql doesn't recognize this as a change so it doesn't up date the field. So what I have had to do is the following:
ctx.DataContext.InvoiceItems.Attach(data, true);
Now all the modifications are generated in the update statement whether there is really a change or not. This works ... seems a bit hackish!

The correct answer is as many pointed out to use the special overload of Attach which accepts a boolean parameter to consider it as modified, (make the mistake of using another overload and it simply won't work):
ctx.DataContext.InvoiceItems.Attach(data, true);
Note however that you still might need to have a "Version" column in the table of type "timestamp".

I had this problem and all the suggestions I'd seen didn't apply or work.
But I found I had made a very simple mistake!
When updating the property I was actually calling a custom Set method (because there were other things that needed to be changed in response to the main property in question).
After hours of head scratching I noticed that my Set method was updating the private member not the public property, i.e. this._Walking = value;
All I had to do was change this to this.Walking = value; and it all started to work!