how to return single row using TableAdapter
Hi I am currently using TableAdapter that returns a dataTable, which is fine to use when result table should have more than one row like :
MyItemsDataTable myItemsDataTable = Adapter.GetAllItems();
but if we need only one row as a result, say开发者_高级运维 an item, which has a particular ID
MyItemsDataSet.MyItemRow itemRow = Adapter.GetItemByID(id)[0];
how can I make Adapter to return one row instead of DataTable. I am using DataSet Designer wizard and gives me two options for putting in SELECT statement
Use SQL statements --> Select which return rows
(returns one or many rows)
Use SQL statements --> Select which returns a single value rows
(returns a single value)
and using similar query
SELECT * from
FROM FOOD_ITEMS
WHERE (ITEM_ID = @ITEM_ID)
Do I need to override this method or add a new one ?
public virtual MyItemsDataSet.MyItemsDataTable GetItemByID(int ITEM_ID)
probably something like
public virtual MyItemsDataSet.MyItemRow GetItemByID(int ITEM_ID)
If so, I cannot do it in designer generated file !! where can I do this ?
Thanks
Create a new Select statement in the Dataset Designer. Use Select which return rows
. Then use the following query:
SELECT TOP 1 * from
FROM FOOD_ITEMS
WHERE (ITEM_ID = @ITEM_ID)
Save this method as GetFirstItemByID()
or something similar.
For the googlers out there, many of the non-MS databases (eg. MySQL) will use the following syntax instead:
SELECT * from
FROM FOOD_ITEMS
WHERE (ITEM_ID = @ITEM_ID)
LIMIT 1
I believe the only way is to access the first row in the data table via an index, as you are doing with this query -
MyItemsDataSet.MyItemRow itemRow = Adapter.GetItemByID(id)[0];
Another thing you should consider is dumping table adapters and using LINQ2SQL instead. LINQ supports the .FIRST() method, which does precisely what you want.
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