I am using code similar to this Support / KB article to return multiple recordsets to my C# program.
But I don't want C# code to be dependant on the physical sequence of the recordsets returned, in order to do it's job.
So my question is, "Is there a way to determine which set of records from a multiplerecordset resultset am I currently processing?"
I know I could probably decipher this indirectly by looking for a unique column name or something per resultset, but I think/hope there is a better way.
P.S. I am using Visual Studio 2008 Pro & SQL Server 2008 Express Edition.
No, because the SqlDataReader is forward only. As far as I know, the best you can do is open the reader with KeyInfo and inspect the schema data table created with the reader's GetSchemaTable method (or just inspect the fields, which is easier, but less reliable).
I spent a couple of days on this. I ended up just living with the physical order dependency. I heavily commented both the code method and the stored procedure with !!!IMPORTANT!!!, and included an #If...#End If to output the result sets when needed to validate the stored procedure output.
The following code snippet may help you.
Helpful Code
Dim fContainsNextResult As Boolean
Dim oReader As DbDataReader = Nothing
oReader = Me.SelectCommand.ExecuteReader(CommandBehavior.CloseConnection Or CommandBehavior.KeyInfo)
#If DEBUG_ignore Then
'load method of data table internally advances to the next result set
'therefore, must check to see if reader is closed instead of calling next result
Do
Dim oTable As New DataTable("Table")
oTable.Load(oReader)
oTable.WriteXml("C:\" + Environment.TickCount.ToString + ".xml")
oTable.Dispose()
Loop While oReader.IsClosed = False
'must re-open the connection
Me.SelectCommand.Connection.Open()
'reload data reader
oReader = Me.SelectCommand.ExecuteReader(CommandBehavior.CloseConnection Or CommandBehavior.KeyInfo)
#End If
Do
Dim oSchemaTable As DataTable = oReader.GetSchemaTable
'!!!IMPORTANT!!! PopulateTable expects the result sets in a specific order
' Therefore, if you suddenly start getting exceptions that only a novice would make
' the stored procedure has been changed!
PopulateTable(oReader, oDatabaseTable, _includeHiddenFields)
fContainsNextResult = oReader.NextResult
Loop While fContainsNextResult
Because you're explicitly stating in which order to execute the SQL statements the results will appear in that same order. In any case if you want to programmatically determine which recordset you're processing you still have to identify some columns in the result.
Related
I can't find any documentation on how to manager parameters into Database Reader SQL statements?
-> this is a simplified example: I am not looking for scripting a variable to "yesterday" which is easy to express in SQL. That's not the point. I have have more complex variables in the actual SQL statement I'm trying to martial in. I just want to know how to get variables into the SQL form if possible.
-> "you can just do that in JavaScript": the actual queries I need to run are about a hundred lines long, I don't want to maintain and debug a query build by concatenating strings and then deal with escaping 'quoted' things everywhere in the SQL. I really prefer to maintain an actual SQL statement that copy/paste works in a SQL IDE.
How do we pass in parameters into the SQL block at the bottom of the Database Reader form?
SELECT patientsex, visitnumber, samplereceived_dt, sr_d, sr_t, orderpriority, orderrequestcode, orderrequestname
FROM mydata.somedata
WHERE sr_d = (${DateUtil.getCurrentDate('yyyyMMdd')})::integer;
JavaScript is the feasible way to achieve this, with SQL statements defined inside Mirth connect or have the SQL statements bundled in a stored procedure then use SQL server's Exec command within Mirth connect to call the stored procedure while passing the parameters (interestingly using JavaScript).
For example
var dbConn;
try {
dbConn = DatabaseConnectionFactory.createDatabaseConnection('','DB:Port\instance','user','pass');
var paramList = new java.util.ArrayList();
paramList.add($('patientId'));
paramList.add($('lastName'));
paramList.add($('firstName'));
var result = dbConn.executeCachedQuery("SELECT * FROM patients WHERE patientid = ? AND lastname = ? AND firstname = ?) ",paramList);
while (result.next()) {
//you can reference by column index like so...
//result.getString(1);
}
} finally {
if (dbConn) {
dbConn.close();
}
}
Should be noted that the parameters you add to the list MUST be in order.
Right now, I am just working with powershell, but I plan on porting this concept to JScript and using the .NET jsc with ActiveXObject('Access.Application'). I have opened my query using $accessapp.DoCmd.OpenQuery("MyQuery") and I can see that it is loaded using $accessapp.CurrentData.AllQueries("MyQuery"). I would like to use $accessapp.DoCmd.OutputTo(acOutputQuery, "MyQuery",<acFormat>, <file>), but for some reason, I keep getting the error:
Unexpected token 'acOutputQuery' in expression or statement
Just running $accessapp.DoCmd.OutputTo shows that is what is expected:
void OutputTo (AcOutputObjectType, Variant, Variant, Variant, Variant, Variant, Variant, AcExportQuality)
Every resource I have seen, including the Microsoft OutputTo documentation uses the acOutputObjectType in this manner, so I am completely stumped.
Okay, sorry it took me a while to get back. Thanks to #HansUp for leading me down the correct path. I Used the AcOutputObjectType enumeration link he posted as well as the MS Constants Enumeration. I'll give both a powershell example and an MS JScript one. I'll use acOutputQuery and xcFormatTXT as 1 and "MS-DOS" respectively here, but there are many others in the two links above.
powershell:
$acc = New-Object -com Access.Application
$acc.OpenCurrentDatabase("<path_to_file>.accdb")
$acc.DoCmd.OpenQuery("MyQuery")
$acc.DoCmd.OutputTo(1,"MyQuery","MS-DOS", "<path_to_output_file>.txt")
MS JScript:
function writeToTextFile(dbPath,queryName,outputPath){
var acc = new ActiveXObject("Access.Application"); //create new COM instance
acc.OpenCurrentDatabase(dbPath+".accdb"); //open the database
if(!acc.CurrentData.AllQueries(queryName).IsLoaded){
acc.DoCmd.OpenQuery(queryName); //load the query if it is not loaded yet
}
acc.DoCmd.OutputTo(1,queryName,"MS-DOS",outputPath+".txt"); //write to file
}
These two are kind of quick and dirty. Since I have this working in JScript now, I will probably make a writeToFile() function that takes the format as an argument. I considered using an object to map the name string to the enumeration, but I don't know how useful that would actually be. I suppose if you wanted, you could take the output object as an argument, too, but I only plan to use query objects for now.
I have a Form which will help me to filter out the records I want for my Report. The button will open the Report On Click.
This is the code in the button:
Private Sub Open_OEE_Click()
DoCmd.OpenReport "OEE_Report", acViewReport, , , acWindowNormal
End Sub
I keep getting the error:
I also have placed the query in my report under the Record Source as:
SELECT * FROM 3_OEE WHERE ((([3_OEE].RecordID)=Forms![3_OEE_Report]!cboRecordID) And (([3_OEE].Date_Recorded)=DateValue(Forms![3_OEE_Report]!Date_Recorded)) And (([3_OEE].MC_No)=Forms![3_OEE_Report]!cboMCNo) And (([3_OEE].Product)=Forms![3_OEE_Report]!cboProduct));
I want to search based on one criteria (text box or combo box) and not all four at once.
Am I missing out something?
MS-Access does tend to go a bit overboard with the brackets. Make the report's Record Source a bit easier to read by trimming out the unnecessary ones. You also need to get your date criterion in the right format - Access always uses US formatting in SQL queries and needs # signs around the date:
SELECT * FROM 3_OEE
WHERE [3_OEE].RecordID = Forms![3_OEE_Report]!cboRecordID
And [3_OEE].Date_Recorded = Format(Forms![3_OEE_Report]!Date_Recorded, "\#mm/dd/yyyy\#")
And [3_OEE].MC_No = Forms![3_OEE_Report]!cboMCNo
And [3_OEE].Product = Forms![3_OEE_Report]!cboProduct;
I would also suggest creating a named query for this and setting the report's Record Source to the named query. You can then test the query in isolation without having to run the report (but make sure the Form is open and the relevant controls are populated).
I asked for help from another source.
Answer to Question
I am new to using intersytems cache and face an issue where I am querying data stored in cache, exposed by classes which do not seem to accurately represent the data in the underlying system. The data stored in the globals is almost always larger than what is defined in the object code.
As such I get errors like the one below very frequently.
Msg 7347, Level 16, State 1, Line 2
OLE DB provider 'MSDASQL' for linked server 'cache' returned data that does not match expected data length for column '[cache]..[namespace].[tablename].columname'. The (maximum) expected data length is 5, while the returned data length is 6.
Does anyone have any experience with implementing some type of quality process to ensure that the object definitions (sql mappings) are maintained in such away that they can accomodate the data which is being persisted in the globals?
Property columname As %String(MAXLEN = 5, TRUNCATE = 1) [ Required, SqlColumnNumber = 2, SqlFieldName = columname ];
In this particular example the system has the column defined with a max len of 5, however the data stored in the system is 6 characters long.
How can I proactively monitor and repair such situations.
/*
I did not create these object definitions in cache
*/
It's not completely clear what "monitor and repair" would mean for you, but:
How much control do you have over the database side? Cache runs code for a data-type on converting from a global to ODBC using the LogicalToODBC method of the data-type class. If you change the property types from %String to your own class, AppropriatelyNamedString, then you can override that method to automatically truncate. If that's what you want to do. It is possible to change all the %String property types programatically using the %Library.CompiledClass class.
It is also possible to run code within Cache to find records with properties that are above the (somewhat theoretical) maximum length. This obviously would require full table scans. It is even possible to expose that code as a stored procedure.
Again, I don't know what exactly you are trying to do, but those are some options. They probably do require getting deeper into the Cache side than you would prefer.
As far as preventing the bad data in the first place, there is no general answer. Cache allows programmers to directly write to the globals, bypassing any object or table definitions. If that is happening, the code doing so must be fixed directly.
Edit: Here is code that might work in detecting bad data. It might not work if you are doing cetain funny stuff, but it worked for me. It's kind of ugly because I didn't want to break it up into methods or tags. This is meant to run from a command prompt, so it would have to be modified for your purposes probably.
{
S ClassQuery=##CLASS(%ResultSet).%New("%Dictionary.ClassDefinition:SubclassOf")
I 'ClassQuery.Execute("%Library.Persistent") b q
While ClassQuery.Next(.sc) {
If $$$ISERR(sc) b Quit
S ClassName=ClassQuery.Data("Name")
I $E(ClassName)="%" continue
S OneClassQuery=##CLASS(%ResultSet).%New(ClassName_":Extent")
I '$IsObject(OneClassQuery) continue //may not exist
try {
I 'OneClassQuery.Execute() D OneClassQuery.Close() continue
}
catch
{
D OneClassQuery.Close()
continue
}
S PropertyQuery=##CLASS(%ResultSet).%New("%Dictionary.PropertyDefinition:Summary")
K Properties
s sc=PropertyQuery.Execute(ClassName) I 'sc D PropertyQuery.Close() continue
While PropertyQuery.Next()
{
s PropertyName=$G(PropertyQuery.Data("Name"))
S PropertyDefinition=""
S PropertyDefinition=##CLASS(%Dictionary.PropertyDefinition).%OpenId(ClassName_"||"_PropertyName)
I '$IsObject(PropertyDefinition) continue
I PropertyDefinition.Private continue
I PropertyDefinition.SqlFieldName=""
{
S Properties(PropertyName)=PropertyName
}
else
{
I PropertyName'="" S Properties(PropertyDefinition.SqlFieldName)=PropertyName
}
}
D PropertyQuery.Close()
I '$D(Properties) continue
While OneClassQuery.Next(.sc2) {
B:'sc2
S ID=OneClassQuery.Data("ID")
Set OneRowQuery=##class(%ResultSet).%New("%DynamicQuery:SQL")
S sc=OneRowQuery.Prepare("Select * FROM "_ClassName_" WHERE ID=?") continue:'sc
S sc=OneRowQuery.Execute(ID) continue:'sc
I 'OneRowQuery.Next() D OneRowQuery.Close() continue
S PropertyName=""
F S PropertyName=$O(Properties(PropertyName)) Q:PropertyName="" d
. S PropertyValue=$G(OneRowQuery.Data(PropertyName))
. I PropertyValue'="" D
.. S PropertyIsValid=$ZOBJClassMETHOD(ClassName,Properties(PropertyName)_"IsValid",PropertyValue)
.. I 'PropertyIsValid W !,ClassName,":",ID,":",PropertyName," has invalid value of "_PropertyValue
.. //I PropertyIsValid W !,ClassName,":",ID,":",PropertyName," has VALID value of "_PropertyValue
D OneRowQuery.Close()
}
D OneClassQuery.Close()
}
D ClassQuery.Close()
}
The simplest solution is to increase the MAXLEN parameter to 6 or larger. Caché only enforces MAXLEN and TRUNCATE when saving. Within other Caché code this is usually fine, but unfortunately ODBC clients tend to expect this to be enforced more strictly. The other option is to write your SQL like SELECT LEFT(columnname, 5)...
The simplest solution which I use for all Integration Services Packages, for example is to create a query that casts all nvarchar or char data to the correct length. In this way, my data never fails for truncation.
Optional:
First run a query like: SELECT Max(datalength(mycolumnName)) from cachenamespace.tablename.mycolumnName
Your new query : SELECT cast(mycolumnname as varchar(6) ) as mycolumnname,
convert(varchar(8000), memo_field) AS memo_field
from cachenamespace.tablename.mycolumnName
Your pain of getting the data will be lessened but not eliminated.
If you use any type of oledb provider, or if you use an OPENQUERY in SQL Server,
the casts must occur in the query sent to Intersystems CACHE db, not in the the outer query that retrieves data from the inner OPENQUERY.
I have this ADO.NET command object and I can set some parameters and execute it successfully.
_mergecommand.Parameters.Add(new SqlParameter("values", SqlDbType.Structured));
_mergecommand.Parameters["values"].TypeName = "strlist";
_mergecommand.Parameters["values"].Direction = ParameterDirection.Input;
_mergecommand.Parameters["values"].Value = valuelist;
_mergecommand.ExecuteNonQuery();
This works fine. But I want to prepare this command before executing it because I need to run this millions of times. I am using SQL Server 2008. I get this error if I try to prepare it
SqlCommand.Prepare method requires all variable length parameters to have an explicitly set non-zero Size.
Any idea how to do this?
This is old, but there does appear to be a correct answer which is to use -1 as the size, e.g.:
_mergecommand.Parameters.Add(new SqlParameter("values", SqlDbType.Structured, -1));
If you have to do it millions of times using a command like this is probably not a good strategy.
Can you serialize your data into an XML string and pass that as a single argument? That will be considerably less load on your network and SQL Server.... although it will probably hit your client a lot harder.
If you are dead set on doing it that way, maybe what you are looking for is an overload of the SqlCommand.Parameters.Add method:
_mergecommand.Parameters.Add("#values", System.Data.SqlDbType.NVarChar, 100).Value = foo;
is that more like what you wanted?