Posted on 2002-07-11
Last Modified: 2011-04-14
Hi experts,

I discovered the Data Environement Object, and I can't really get it to work my way.

First what I want it to get the Max Value of a field, and I was hoping to accomplish this with a single call to the command like:

MySort = MyDE.MyCommand (MyParent)

MyTable (table name) has the following fields:

MyId, MyName, MyParent, MySort

I would like to get the maximum value of the MySort field grouped by MyParent. I would like to do this all in the Data Environement (Command object) and not in the database directly. I will tell you what I did, and you please tell me where I went wrong ...

1. I created a Command Object and used a SQL-statement like:

SELECT MyTable.* FROM MyTable ORDER BY MyParent, MySort

Resulting Recordset:

MyId     MyName             Parent     Sort
0     MyGroups     0     0
6     Main1             0     1
7     Main2               0     2
1     Main3             0     4
5     Main4             0     5
2     Main5             0     6
3     Sub1             1     1
4     Sub2         1     2

2. I grouped it by MyParent.

3. I put the aggregate to Max (field: MySort)

Now the result is:

My parent / My Sort
0  /  6
1  /  2

4. In order to get a parameter I change the SQL to:

SELECT tblGroups.* FROM tblGroups WHERE GrpParent = ? ORDER BY GrpParent, GrpSort

Now the code looks like:

MyDE.ByParent (MyParent)

MyDE = Data Environement Object name
ByParent = Command objects - grouping name
MyParent = Variable that contains a parameter value

That's what I want. Then I thought I need only 1 value to be returned, not a recordset. I was thinking of adding a output parameter, and uncheck the "recordset returning" checkbox on the advanced tab of the command object properties.

How can I put an output parameter at design-time?
How can I access this value now? In code I mean.
How can I set the default value to "1" in case there are no records that match the criteria?
How can I add the value "1" to the returned value in the command object itself?

The command name is MyCommand.
The Grouping name is ByParent
The Aggregate name is MaxSort

I hope you understand.

Thanks ...

Question by:beni_luedi
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Expert Comment

ID: 7149976
To return only one record per MyParent, you can write a SQL statement like this:-
sSQL =  " SELECT Max(MySort), MyParent" & _
          " FROM tblGroups" & _
         " WHERE GrpParent = ? " & _
      " GROUP BY MyParent"


Author Comment

ID: 7150927
How can I put an output parameter at design-time?
How can I access this value now? In code I mean.
How can I set the default value to "1" in case there are no records that match the criteria?
How can I add the value "1" to the returned value in the command object itself?

Expert Comment

ID: 7151486
Where do you want to put the output parameter?
Can you not use ADODB object model to accomplish your requirement?

Author Comment

ID: 7151538
I want to put the output parameter together with the input parameter into the command object of the data environement designer (at design time).

Do you mean writing code to create a ADO command object with it's properties and parameters?

I would like to know if I can accoplish the same directly in the data environment's command object at design time.

Is this possible? If yes, HOW?

Accepted Solution

AlonHirsch earned 100 total points
ID: 7153744

Typically OUTPUT parameters are used when you call a stored procedure in SQL Server (ORACEL etc.).
The stored procedure uses Parameters for the query and has the option of returning data in one or more of the parameters.

You can't use output parameters with a direct SQL query as you are trying.


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