import msrdo20.*;
 import com.ms.com.*;
 
 public class HelloRDO{
 
   public static void main(String args[]){ 
     //*** get interface reference to rdoEngine
     _rdoEngine eng = new rdoEngine();
     //*** create a variant object for default parameters
     Variant vDef = new Variant();
     vDef.noParam();
     //*** create the environment
     _rdoEnvironment env = eng.rdoCreateEnvironment("", "", "");
     //*** create a DSN-less connect string
     String sConnect;
     sConnect = "DRIVER=SQL Server;SERVER=Fred;DATABASE=Customers;UID=sa;PWD=";
     Variant vConnect = new Variant(sConnect);
     //*** establish a connection to the DBMS
     _rdoConnection conn = env.OpenConnection("", vDef, vDef, vConnect, vDef);
     //*** create a SQL statement
     String sSQL = "SELECT LastName, FirstName" + 
                   " FROM Customers" + 
                   " WHERE LastName BETWEEN 'A' AND 'L'" +
                   " ORDER BY LastName, FirstName";
     //*** open up resultset
     _rdoResultset rs = conn.OpenResultset(sSQL, vDef, vDef, vDef);
     //*** retrieve a reference to the columns collection
     rdoColumns columns = rs.getrdoColumns();
     //*** create variables to reference columns
     _rdoColumn clmLastName;
     _rdoColumn clmFirstName;
     Variant vLastName = new Variant("LastName");
     Variant vFirstName = new Variant("FirstName");
     clmLastName = columns.getItem(vLastName);
     clmFirstName = columns.getItem(vFirstName);
     //*** create variant variables to store column values
     Variant valueLastName;
     Variant valueFirstName;
     //*** enumerate through recordset
     while (!rs.getEOF()){
       valueLastName = clmLastName.getValue();
       valueFirstName = clmFirstName.getValue();
       String sName = valueLastName + ", " + valueFirstName;
       System.out.println(sName);
       rs.MoveNext();
     }  
   }
 }

Figure 4   Available RDO Cursor Types

Cursor Type	Constant	Updatable	New Rows	Concurrency
Forward-only (default)	rdOpenForwardOnly	No	Not visible	Good
Snapshot	rdOpenStatic	No (usually)	Not visible	OK
Keyset	rdOpenKeyset	Yes	Not visible	OK
Dynamic Keyset	rdOpenDynamic	Yes	Visible	Poor

Figure 5   Resultset Locking Schemes

Type	Constant	Concurrency
Shared locks (default)	rdConcurReadOnly	Best
Pessimistic	rdConcurLock	Very bad
Optimistic	rdConcurRowVer	OK
Optmistic	rdConcurValues	OK

Figure 6   Executing a Stored Procedure

 //*** assume 'conn' is an open rdoConnection object
 
 //*** create ODBC string to execute stored procedure
 Variant vSQL = new Variant("{ ? = call AddEmployee(?, ?, ?) }");
 //*** create rdoQuery object
 rdoPreparedStatement query = conn.CreateQuery("", vSQL);
 //*** retrieve a reference to the parameters collection
 rdoParameters params;
 params = query.getrdoParameters();
 //*** assign parameter direction for return value
 Variant vIndex = new Variant();
 vIndex.putInt(0);
 params.getItem(vIndex).putDirection(DirectionConstants.rdParamReturnValue);
 //*** assign values for input parameters
 vIndex.putInt(1);
 params.getItem(vIndex).putValue( new Variant("Bubba") );
 vIndex.putInt(2);
 params.getItem(vIndex).putValue( new Variant("Van der Weigh") );
 vIndex.putInt(3);
 params.getItem(vIndex).putValue( new Variant("Associate") );
 //*** exectue the stored procedure
 query.Execute(vDef);
 //*** examine the return value
 vIndex.putInt(0);
 String sRV = params.getItem(vIndex).getValue().toString();
 System.out.println("Return value = " + sRV);

Figure 7   RDO Exception Handler

 //*** _rdoEngine variable must be accessible 
 //*** to both try and catch block
 _rdoEngine eng = null;
 
 try{
   eng = new rdoEngine();
   //*** try something risky that might raise an RDO exception
 }
 catch(ComException eCom){ 
 
   String strError = new String();
 
   //*** examine COM exception info directly
   strError = "COM HResult: " + eCom.getHResult() + "\n\n";
   //*** here's a secret trick to get error code from HRESULT
   strError +="RDO error code: " + (eCom.getHResult() & 65535) + "\n\n";
 
   //*** Use rdoErrors collection to examine rdoError objects
   //*** Use rdoError objects to determine error number and description
   rdoErrors errs = eng.getrdoErrors();
   Variant var = new Variant();
   for (int n = 0; n < errs.getCount(); n++){
     var.putInt(n);
     rdoError err = errs.getItem(var);
     strError += "RDO error no:" + err.getNumber() + "\n" + 
                 "Description:" + err.getDescription();
   }
   System.out.println(strError);
 }