How to define a CHAR (ORACLE) column in Nhibernate?

I am starting to work with Nhibernate and Oracle for a project.

The database is Oracle 9.2 and I can't change the schema or anything.

I am using NH3.0 and the Oracle.DataAccess.dll ver 2.111.7.20.

So far I've mapped a couple of table and have done some queries. Everything works pretty well. I've bumped into a problem now and I don't know how to fix it.

The company who's designed the database thought it was a good idea to create all the alphanumeric fields as CHAR instead of VARCHAR or VARCHAR2.

I've mapped all these columns as String and my classes have String fields defined. Later on I was trying to load an entity by its primary key, defined as CHAR(10) in Oracle. The key I was trying to load is only 7 characters long

EG: 'CI00252' Apparently my entity can't be loaded. Profiling the query with NHProf I can see that my query is fine and if I try to execute it in Oracle Sql-Developer I get the resultset. I can only manage to make it work if I pad my string like this 'CI00252 '.

Considering that most of the fields defined on the database are CHAR, it is impossible for me to pad everything before executing the query.

What can I do to fix this problem?

PS: I've seen some other people with the same problem here but I couldn't find any appropriate answer.

UPDATE:

I was reading a blog and this guy had a similar problem with another data-type.I've tried to adpapt the code

public SqlType[] SqlTypes
    {
        get
        {
                SqlType[] types = new SqlType[1];
                types[0] = new SqlType(DbType.StringFixedLength);
                return types;
                }
    }

**

and, apparently, everything is working but ... I don't know why.

using System;
using System.Data;
using NHibernate;
using NHibernate.SqlTypes;
using NHibernate.UserTypes;

namespace ConsoleOracleNhibernate.OracleTypes
{
    public class CharUserType : IUserType
    {
        public object NullSafeGet(IDataReader rs, string[] names, object owner)
        {
            string resultString = (string)NHibernateUtil.String.NullSafeGet(rs, names[0]);
            if (resultString != null)
                return resultString.Trim();
            re开发者_如何转开发turn null;
        }

        public void NullSafeSet(IDbCommand cmd, object value, int index)
        {
            if (value == null)
            {
                NHibernateUtil.String.NullSafeSet(cmd, null, index);
                return;
            }

            value = ((String)value).Trim();

            NHibernateUtil.String.NullSafeSet(cmd, value, index);
        }

        public object DeepCopy(object value)
        {
            if (value == null) return null;
            return string.Copy((String)value);
        }

        public object Replace(object original, object target, object owner)
        {
            return original;
        }

        public object Assemble(object cached, object owner)
        {
            return DeepCopy(cached);
        }

        public object Disassemble(object value)
        {
            return DeepCopy(value);
        }

        public SqlType[] SqlTypes
        {
            get
            {
                SqlType[] types = new SqlType[1];
                types[0] = new SqlType(DbType.StringFixedLength);
                return types;
            }
        }

        public Type ReturnedType
        {
            get { return typeof(String); }
        }

        public bool IsMutable
        {
            get { return false; }
        }

        public new bool Equals(object x, object y)
        {
            if (x == null || y == null) return false;
            return x.Equals(y);
        }

        public int GetHashCode(object x)
        {
            return x.GetHashCode();
        }
    }
}

and my mapping:

<key-property name="CustomerCode" column="ANCOCO" type="ConsoleOracleNhibernate.OracleTypes.CharUserType, ConsoleOracleNhibernate" length="10"></key-property>

Is there anyone here who can try to help me to understand what's happening?

My answer is in the update of the question.