How can I execute a case-insensitive search?

Question

I have created a table
CREATE TABLE parsPatient
     patPARSID VARCHAR2(40),               
     patFirstName VARCHAR2(30),           
     patMiddleName VARCHAR2(30),          
     patLastName VARCHAR2(30),               
     patDOB DATE,                                    
     CONSTRAINT parsPatient_PK PRIMARY KEY (patPARSID) ENABLE
   )and I would like to search the patLastName field for all patients that match a wildcard (i.e. I want to see Abcd, ABcd, AB, and abcd when I search for "AB%".
Using Oracle Database 10g Express Edition (10.2), I have done the following successfully:
SQL> alter session set nls_comp='LINGUISTIC';
SQL> select count(patparsid) from parspatient where patlastname like 'ab%';
COUNT(PATPARSID)
               7However, when I try to do this using .NET, I get 0 rows. I'm doing the following (simplified, hopefully, for posting):
DataSet dsResults = new DataSet("patients");
try
     // Establish connection
     OracleConnection cn = new OracleConnection();
     cn.ConnectionString = settings.ConnectionString;
     cn.Open();
     cn.ClientId = settings.CurrentUser;
     // Set the linguistic mode
     OracleCommand command = new OracleCommand();
     command.Connection = cn;
     command.BindByName = true;
     command.CommandText = "ALTER SESSION SET NLS_COMP='LINGUISTIC'";
     command.CommandType = CommandType.Text;
     command.Parameters.Clear();          // Remove all parameters, if any.
     int iValue = command.ExecuteNonQuery(); // This returns a -1 -- is that normal?
     command.CommandText = "ALTER SESSION SET NLS_COMP='ANSI'";
     iValue = command.ExecuteNonQuery();
     command.CommandText = "SELECT patPARSID FROM parsPatient WHERE patLastName LIKE 'ab%'";
     OracleDataAdapter adapter = new OracleDataAdapter();
     adapter.SelectCommand = command;
     adapter.Fill(dsResults, "SearchResults");
     // Clean up
     command.Dispose();
     command = null;
     cn.Close();
     cn.Dispose();
     cn = null;
catch (OracleException oex)
     LogDBError("TestCaseInsensitiveSearch", oex);
Any help/pointers would be greatly appreciated!

Answer 1

Hi,
I think the Express Edition comes with the HR sample schema, so here is a quick and dirty sample that uses the HR schema:
using System;
using System.Data;
using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;
namespace CaseInsensitiveTest
  class Program
    // change connection string for your env.
    private const string constr = "user id=hr; password=hr; data source=lt10gr2; enlist=false; pooling=false";
    // simple statement for testing
    private const string sql = "select last_name from employees where last_name like 'a%' order by last_name";
    static void Main(string[] args)
      // get a connection
      OracleConnection con = new OracleConnection(constr);
      con.Open();
      // get globalization object to set values
      OracleGlobalization glb = OracleGlobalization.GetThreadInfo();
      glb.Sort = "BINARY_CI";
      glb.Comparison = "LINGUISTIC";
      // set new globalization (nls) values for the session
      con.SetSessionInfo(glb);
      // get command object and set statement to execute
      OracleCommand cmd = con.CreateCommand();
      cmd.CommandText = sql;
      // get a data reader
      OracleDataReader dr = cmd.ExecuteReader();
      // loop through the reader and display names
      while (dr.Read())
        Console.WriteLine("Last Name = {0}", dr[0].ToString());
      // clean up
      glb.Dispose();
      cmd.Dispose();
      con.Dispose();
}The above code should result in:
Last Name = Abel
Last Name = Ande
Last Name = Atkinson
Last Name = AustinHope that helps a bit.
- Mark