I am using ASP classic with ADO, connecting to SQL Server 2008.
I inherited this code and it is so mangled that I will try to recreate the relevant parts. If you need more detail or I left something out, please let me know.
I create a command and add parameters
oCmd.CommandType = adCmdStoredProc
...
oCmd.Parameters.Append oCmd.CreateParameter("#MyOutputParam", adInteger, adParamOutput, 4, NULL)
Later, I open a reader from that command:
oRS.Open oCmd, , adOpenForwardOnly, adLockReadOnly
After that, while oRS is open but before I've read any records or values, I try to get the output parameter's value using one of the lines below:
val1 = oCmd("#MyOutputParam")
val2 = oCmd("#MyOutputParam").Value
val3 = oCmd.Parameters("#MyOutputParam").Value
All three (val1, val2, val3) variables are DB NULL.
I have confirmed that running the SP in query analyzer returns a value to the #MyOutputParam parameter:
declare #p33 int
exec usp_GetResultAndOutput 1, 2, 3, #p33 output
select #p33
That returns a recordset of my expected records and a second recordset showing a number in a single row.
I've even tried calling rs.NextRecordset before attempting to get the output parameter and that didn't work.
Is there some other way that I need to be handling Output parameters?
Is it okay that I am returning a recordset and output parameters?
Output parameters cannot be retrieved until all the recordsets are enumerated until the end. Just think, how could the client possibly retrieve the output value of a parameter before the execution finishes? The Execute() call is simply starting the execution, the batch continues to execute on the server until all results are returned. While a client is iterating over a resultset produced by a SELECT the batch is executing that SELECT. The value of the output parameter is known only at the end of the batch. Therefore is not possible to know the output parameter value until the batch finished, which implies that all statements have executed, which in turn requires that all resultsets were consumed (iterated) by the client.
This is the canonical form of parsing a set of results:
do
{
while (rs.MoveNext)
{
// do something with the row
}
} while (Not rs.NextRecordset Is Nothing)
// now is safe to read the out param
response.write oCmd("#MyOutput")
As far as I can test the only thing that matters this is the CursorLocation. As long as the CursorLocation is set to adUseClient (3), the output parameters can be accessed anytime after the Execute. Any of the following do that
oConn.CursorLocation = adUseClient
or
oRs.CursorLocation = adUseClient
This is tested on SQL 2008 R2, IIS/ASP on Windows 7 and with SQLOLEDB provider.
Related
In sqlserver I have a function which generates a complex xml of all products with several tables joined: location, suppliers, orders etc.
No problem in that, it runs in 68 sec and produces around 450MB.
It should only be called occationally during migration to another server, so it doesn't matter it takes some time.
I want to make this available for download over webserver.
I've tried some variations of this in classic asp:
Response.Buffer = false
set rs=conn.execute("select cast(dbo.exportXML() as varchar(max)) as res")
response.write rs("res")
But I just get a standard
An error occurred on the server when processing the URL. Please contact the system administrator.
If you are the system administrator please click here to find out more about this error.
Not my usual custom 500-errorhandler, so I'm not sure how to find the error.
The problem is in response.write rs("res"), if i just do
temp = rs("res")
the script runs, but displays nothing of cause; if I then
response.write temp
I get the same failure.
So the problem is writing such a ling string.
Can I save the file from tsql directly; and run the job periodically from sql agent?
I found that there seems to be a limit on how much data can be written at once using Response.Write. The workaround I used was to break the data into chunks like this:
Dim Data, Done
Done = False
Do While Not Done
Data = RecordSet(0).GetChunk(8192)
If Not Len(Data) = 0 Then
Response.Write Data
Else
Done = True
End If
Loop
Try this:
Response.ContentType = "text/xml"
rs.CursorLocation = 3
rs.Open "select cast(dbo.exportXML() as varchar(max)) as res",conn
'Persist the Recordset in XML format to the ASP Response object.
'The constant value for adPersistXML is 1.
rs.Save Response, 1
I have a customer setup that uses stored procedures to return data from its SQL Server database.
Those stored procedures are all built the same way - they take a bunch of input parameters, and they return:
the first is just a single row, single column with the result code (type INT) - 0 for success, some other values otherwise; if the value is 0, then there's a second result set that contains the actual data
the second result set can be anything - any number of columns and rows
I'm trying to create a "generic" way to interface with this system, and my attempt is this:
create a class that takes stored procedure name and input parameters
a return type that contains both an ErrorCode INT property as well as a DataTable results property
However, I'm having trouble getting this to work with ADO.NET and SQL Server 2008 R2.
My code boils down to this:
public MyResultType CallService(string procedureName, MyParameters parameters)
{
MyResultType result = new MyResultType { ErrorCode = 0 };
using (SqlConnection conn = new SqlConnection(_connectionString))
using (SqlCommand cmd = new SqlCommand(procedureName, conn))
{
cmd.CommandType = CommandType.StoredProcedure;
SetupParameters(cmd, parameters);
// open connection, execute the stored procedure
conn.Open();
using (SqlDataReader rdr = cmd.ExecuteReader())
{
// get the first result set - the status code, one row, one column of type INT
while (rdr.Read())
{
result.ErrorCode = rdr.GetInt32(0);
}
// if we got a "0" (success) -> go to the next result set and load it into the table
if(result.ErrorCode == 0 && rdr.NextResult())
{
result.ResultTable = new DataTable();
result.ResultTable.Load(rdr);
int colCount = result.ResultTable.Columns.Count;
int rowCount = result.ResultTable.Rows.Count;
}
rdr.Close();
}
conn.Close();
}
return result;
}
My issue is: the call to the stored procedure works just fine, the error code = 0 is picked up just fine, the data table is created and the number of columns is the expected value - but there are NO ROWS loaded...
I've been trying everything I can think of to get those rows into the DataTable - no luck. And of course - if I execute this very same stored procedure in SQL Server Management Studio, everything works just fine, I get my ErrorCode=0 and my result set of 18 columns and 5 rows - no problem....
What am I missing? Can anyone spot the problem in my code? Why aren't the rows of the second result set loaded (but the columns are being detected, it seems)?
The code as published works fine - there was a difference between how I call it from C# and in SQL Server Management Studio : NULL handling.
I had some input parameters set to int and thus provided a 0 value to the stored procedure, while it really expected to get a NULL if the value isn't defined......
Stupid rookie mistake..... SORRY GUYS! And thanks for your inputs!
The DataTable.Load method implicitly calls the NextResult method, so combining that with your explicit call, it is advancing to a resultset that isn't there. You should remove your own call to NextResult if you want to use DataTable.Load or loop through and fill a datatable yourself.
We are in the process to migrate our SQL 2000 box to SQL 2008. But we ran into an issue; when a result set (rows or not) is returned by using a query that has a UNION. Later in the code we try to add a new row and assign field to it but because a UNION was used, when we try to assign a value to the field it gives us a Multiple-step operation generated errors. Check each status value. error. We tried the following code on a Windows XP & Windows 7 and got the same result. But when we change our connection string to point back to our SQL 2000 box we don't get that error any more.
The following example show the problem we are having.
var c = new ADODB.Connection();
var cmd = new ADODB.Command();
var rs = new ADODB.Recordset();
object recordsAffected;
c.Open("Provider=SQLOLEDB;Server=*****;Database=*****;User Id=*****;Password=*****;");
cmd.ActiveConnection = c;
cmd.CommandType = ADODB.CommandTypeEnum.adCmdText;
cmd.CommandText = "create table testing2008 (id int)";
cmd.Execute(out recordsAffected);
try {
cmd.CommandText = "select * from testing2008 union select * from testing2008";
rs.CursorLocation = ADODB.CursorLocationEnum.adUseClient;
rs.Open(cmd, Type.Missing, ADODB.CursorTypeEnum.adOpenDynamic, ADODB.LockTypeEnum.adLockBatchOptimistic, -1);
rs.AddNew();
rs.Fields["id"].Value = 0; //throws exception
rs.Save();
}
catch (Exception ex) {
MessageBox.Show(ex.ToString());
}
finally {
cmd.CommandText = "drop table testing2008";
cmd.Execute(out recordsAffected);
c.Close();
}
The link below is an article that gives a great breakdown of the 6 scenarios this error message can occur:
Scenario 1 - Error occurs when trying to insert data into a database
Scenario 2 - Error occurs when trying to open an ADO connection
Scenario 3 - Error occurs inserting data into Access, where a fieldname has a space
Scenario 4 - Error occurs inserting data into Access, when using adLockBatchOptimistic
Scenario 5 - Error occurs inserting data into Access, when using Jet.OLEDB.3.51 or ODBC driver (not Jet.OLEDB.4.0)
Scenario 6 - Error occurs when using a Command object and Parameters
http://www.adopenstatic.com/faq/80040e21.asp
Hope it may help others that may be facing the same issue.
It is type mismatch, try
rs.Fields["id"].Value = "0";
or make sure you assign a Variant to the value.
Since I posted this problem, we figured out that the problem was when you do a union the attributes on the fields are not bound (i.e. the attributes: basecatalog, basetable & basecolumn are empty) to remedy our problem we had to force the values of those attributes, by saving the recordset to xml (adPersistXML), change the xml and reopen the recordset from the xml. This rebound the fields and we were able to continue. We know this may not be the most efficient solution, but it was for an older app and we didn't want to rewrite the sql statements. It looks like the main error Multiple-step operation generated errors. Check each status value. is related to when an error occurs when a value is assigned to a field.
Two things I can think of... Make sure your "ID" column will accept a zero (0). Also - I've stopped this issue on one occasion by not using the adUseClient cursor (try server).
Many times this is a type mismatch, trying to stuff a NULL into a non-null column, or attempting to write more characters into a column than it's designed to take.
Hope this helps. - Freddo
Same issue occurred to me the problem was that i violated an object property , in my case it was size the error came out as
"IntegrationException: Problem (Multiple-step operation generated errors. Check each status value.)"
Imports ADODB
Dim _RecordSet As Recordset
_rs.Fields.Append("Field_Name", DataTypeEnum.adVarChar, 50)
_Recordset("Field_Name").Value = _RecordDetails.Field_NameValue
_RecordDetails.Field_NameValue length was more than 50 chars , so this property was violated , hence the error occurred .
I found another scenario:
When I was trying to set the value of a adLongVarChar field in a new record for a memory-only adodb.recordset. In my case, the error was triggered because the string I was passing had a buried unicode character.
I found this error when our legacy application was trying to parse 1/1/0001 12AM date and time. Looks like VB6 recordsets doesn't like that value.
To get rid of the errors, I had to set all the offending dates to null.
I was getting this error when trying to insert/update the field with a value that did not match the table>field type.
For example, the database table > field was
char(1)
however, I was trying to insert/update
"apple"
into the record.
Once I change the inputted value to "a" and it worked.
I am using a function I read about here to merge a series of recordsets that are generated by a stored procedure that is called in a loop. I have used this function before in other stored procedure cases and it has never produced this problem.
The research I did online points to basically one of two reasons:
1) I am trying to update or insert a date/time value that is not formatted correctly into a SQL Server 2005 table
2) I am trying to insert a, for example, CHAR(60) string into a CHAR(50) field.
Reason one is not applicable here since I am not using dates (in datetime format at least).
Reason two seemed to be the most likely issue. So I did a series of Response.Write() to spit out the objField.Name, objField.Type, objField.ActualSize, and if it was a numeric field the objField.Precision and objField.NumericScale.
Let us say that the stored SQL procedure is called twice as I am querying for values that are occurring in the same time frame but 2 different states. The loop I have in the ASP page does a For Each on the state in the state list and calls the stored procedure for each of the elements in the state list. I then call the MergeRecordSets function so it combines the 2 results into one. The general rule is that the data types and sizes of the columns in each resultset must be the same. With my Response.Write() checks of each of the columns returned in the 2 data sets I have found that they are identical. Doing my checks I also found that it breaks on the first column that is a NUMERIC column. The previous columns it was OK with were all CHAR or VARCHAR.
Is there any other reason why this error would come up?
The following is how I am calling the record merger function. The oQueryResult is going to be the final output (the combined records). objSingleRS is the result set returned by the stored procedure.
If oQueryResult Is Nothing Then
Set oQueryResult = objSingleRS
Else
Set oQueryResult = MergeRecordSets(Array(oQueryResult, objSingleRS))
End If
Here is the merge function. The line in which the code breaks is marked below.
Function MergeRecordSets(arrRecordsets)
Dim x, y, objCurrentRS
Dim objMergedRecordSet, objField, blnExists
Set objMergedRecordSet = Server.CreateObject("ADODB.Recordset")
For x=0 To UBound(arrRecordsets)
Set objCurrentRS = arrRecordsets(x)
For Each objField In objCurrentRS.Fields
blnExists = False
For y=0 To objMergedRecordSet.Fields.Count-1
If LCase(objMergedRecordSet.Fields(y).Name) = Lcase(objField.Name) Then
blnExists = True : Exit For
End If
Next
If Not(blnExists) Then
objMergedRecordSet.Fields.Append objField.Name, objField.Type, objField.DefinedSize
'objMergedRecordSet.Fields(objMergedRecordset.Fields.Count-1).Attributes = 32 'adFldIsNullable
End If
Next
Next
objMergedRecordSet.Open
For x=0 To UBound(arrRecordsets)
Set objCurrentRS = arrRecordsets(x)
Do Until objCurrentRS.EOF
objMergedRecordSet.AddNew
For Each objField In objCurrentRS.Fields
If Not(IsNull(objField.Value)) Then
'Response.Write(objField.Name & "<br>")
'Response.Write(objField.Type & "<br>")
objMergedRecordSet.Fields(objField.Name).Value = objField.Value 'Here is where it throws the Error.
End If
Next
objCurrentRS.MoveNext
Loop
Next
objMergedRecordSet.MoveFirst
Set MergeRecordSets = objMergedRecordSet
End Function
Here is the full error message returned:
Microsoft Cursor Engine error '80040e21'
Multiple-step operation generated errors. Check each status value.
/includes/funcs/Common.asp, line 4109
You mentioned that you have numeric columns, but you never set the Precision and NumericScale properties when you create the new Field in objMergedRecordSet. You need to set these properties for adNumeric and adDecimal fields.
objMergedRecordSet.Fields.Append objField.Name, objField.Type, objField.DefinedSize
With objMergedRecordSet.Fields(objField.Name)
.Precision = objField.Precision
.NumericScale = objField.NumericScale
End With
Also make sure you are not trying to put a NULL into a column that will not accept a NULL value. There is also the possibility of a type mismatch to cause this error so make sure you are passing a numeric value.
- Freddo
I have a lot of legacy data access code mainly SqlCommand with Stored Procedure calls that we used to execute alot of Insert statment into an database.
As long as the SQL server has been on the same machine as the application there have been acceptable performace but now are we trying to move some of the data to SQL Azure.
The problem is that our code calls a SP for every record to insert which results in quite a few trips to the database and when not located on the same server it takes some time.
var conn = new SqlConnection("connString")
var cmd = new SqlCommand(conn, "spMyStoreProc");
cmd.Params.Add("#a", SqlDbType.VarChar, 10);
cmd.Params.Add("#b", SqlDbType.Int);
using(conn)
{
conn.Open();
foreach(var rec in recordsToInsert)
{
cmd.Parameters["#a"].Value = rec.A;
cmd.Parameters["#b"].Value = rec.B;
cmd.ExecuteNonQuery();
}
conn.Close();
}
I have tried the code above with and without Transactions.
I have also tried to use a "batch" SQL statement to execute several SPs in every trip to the server.
Like this:
var cmd = new SqlCommand(conn);
cmd.CommandText = "EXEC spMyStoreProc #a='a' #b=2; EXEC spMyStoreProc #a='b' #b=4;"
It greatly increases the performance of the operation but since I have quite a few SPs where every SP has about 20-50 params it gets quite tedious to write this code for all the insert commands in this data access component.
Is this the best way to achive this, or can I somehow tell ADO.NET I want to execute my calls as a batch (havent fount anything suggesting its possible but feel that I atleast should ask) to avoid network latency etc betweeen every single SP call?
If not does anybody know any good way to achive this without having to write it "by hand" and since its a legacy application I can not change the data layer completely.
Is there any applications that can take SqlCommands with parameters and generate the TQL they would execute?
Thanks in advance
You should probably have one stored procedure, that calls all the other stored procedures - it will probably be the least amount of work. So, from the code you only call the stored procedures once... so given that they are the same parameters you are passing every time (because your code seems to imply that) you would basically do something like this:
CREATE PROCEDURE sp_RunBatch(#param1, #param2, etc [all the parameters you need])
AS
exec spMyStoreProc #a='a'
exec spMyStoreProc2 #b='b'
The advantages of this are many, some of which being that its all centralized, and you can even wrap all of them within a transaction, so as not to do dirty inserts (given that they all depend on each other).
Also, if you don't feel like passing 20/30 parameters to each SP, you may want to make a user-table-defined data-type for each set of parameters, that you can pass. So then each SP gets 1 or 2 parameters, and the code becomes much simpler and readable.
EDIT:
This is a good reference for the user-defined table types: http://msdn.microsoft.com/en-us/library/bb675163.aspx
And this is how to pass the table valued types to SQL server: http://msdn.microsoft.com/en-us/library/bb675163.aspx
An alternative to M.R.'s approach would be to send all your parameters as an XML document, then parse the XML document to extract your parameters. This may simplify the interface a bit.
However I think you were on something when you discussed the possibility of chaining all the commands in a single string. But instead of manually building them, consider building an extension method to the SqlCommand object that returns a single string for execution, leveraging the sp_executesql syntax, and execute the entire string in a single pass.
So you would have a loop that looks like this, and you would call a new ToInlineSql extension method:
string sqlCommand = "";
foreach(var rec in recordsToInsert)
{ cmd.Parameters["#a"].Value = rec.A;
cmd.Parameters["#b"].Value = rec.B;
sqlCommand += cmd.ToInlineSql();
}
// execute sqlCommand
The ToInlineSql extension method could look like this (peuso-code, you will have to add certain things such as checking for the data type and so on) [and here is the link to sp_executesql:
public static class SqlCmdExt
{
public static string ToInlineSql(this SqlCommand cmd)
{
string sql = "sp_executesql " + cmd.CommandText ;
foreach (SqlParameter p in cmd.Parameters)
{
sql += ", #" + p.Name + " " + p.DataType.ToString() ;
sql += ", " + p.Name + " = " + p.Value;
}
sql += ";";
return sql;
}
}