How do I map boolean fields in Fluent NHibernate to DB2 iSeries - nhibernate

Question

I have the following code:
private static ISessionFactory CreateSessionFactory()
{
ISessionFactory factory = null;
var cfg = new Configuration();
// Do this to map bool true/false to DB2 char('0') or char('1')
var props = new Dictionary<string, string>();
props.Add("query.substitutions","true=1;false=0");
cfg.AddProperties(props);
cfg.DataBaseIntegration(x =>
{
x.ConnectionString = CONNECTION_STRING;
x.Dialect<DB2400Dialect>();
x.Driver<DB2400Driver>();
});
factory = Fluently.Configure(cfg)
.Mappings(m => m.FluentMappings.AddFromAssembly(Assembly.GetExecutingAssembly()))
.BuildSessionFactory();
return factory;
}
In my POCO, I have the property:
public virtual bool QCCount { get; set; }
In my mapping, I have
Map(x => x.QCCount, "QCNT36");
In DB2, there are no bit fields, only char(1) with '0' or '1'.
As I understand it, the props.Add("query.substitutions","true=1;false=0"); should map these 0's and 1's to boolean POCO objects, however, it doesn't seem to be working.
Do I need to add something to the mapping of the field to tell it to use this?

Answer 1

I found a solution that seems to work.
http://lostechies.com/rayhouston/2008/03/23/mapping-strings-to-booleans-using-nhibernate-s-iusertype/
I changed the 'Y', 'N' to '0' and '1', then map the column and it's processing fine.
Code:
public class CharBoolType : IUserType
{
public bool IsMutable
{
get { return false; }
}
public Type ReturnedType
{
get { return typeof(CharBooleanType); }
}
public SqlType[] SqlTypes
{
get { return new[] { NHibernateUtil.String.SqlType }; }
}
public object NullSafeGet(IDataReader rs, string[] names, object owner)
{
var obj = NHibernateUtil.String.NullSafeGet(rs, names[0]);
if (obj == null) return null;
var trueFalse = (string)obj;
if (trueFalse != "1" && trueFalse != "0")
throw new Exception(string.Format("Expected data to be '0' or '1' but was '{0}'.", trueFalse));
return trueFalse == "1";
}
public void NullSafeSet(IDbCommand cmd, object value, int index)
{
if (value == null)
{
((IDataParameter)cmd.Parameters[index]).Value = DBNull.Value;
}
else
{
((IDataParameter)cmd.Parameters[index]).Value = (bool)value ? "1" : "0";
}
}
public object DeepCopy(object value)
{
return value;
}
public object Replace(object original, object target, object owner)
{
return original;
}
public object Assemble(object cached, object owner)
{
return cached;
}
public object Disassemble(object value)
{
return value;
}
public new bool Equals(object x, object y)
{
if (ReferenceEquals(x, y)) return true;
if (x == null || y == null) return false;
return x.Equals(y);
}
public int GetHashCode(object x)
{
return x == null ? typeof(bool).GetHashCode() + 473 : x.GetHashCode();
}
}
Mapping:
Map(x => x.QCCount, "QCNT36").CustomType<CharBoolType>();

Answer 2

It seems the NHibernate DB2 dialect maps boolean to SMALLINT (https://github.com/nhibernate/nhibernate-core/blob/master/src/NHibernate/Dialect/DB2Dialect.cs):
RegisterColumnType(DbType.Boolean, "SMALLINT");
query.substitutions is for automatically replacing some tokens in your HQL queries with other tokens, and I don't think it affects reading.

Answer 3

If you want to use SMALLINT for boolean columns, you must inherit usertype class from BooleanType
Code:
public class IntBoolUserType : BooleanType, IUserType
{
public new bool Equals(object x, object y)
{
if (ReferenceEquals(x, y)) return true;
if (x == null || y == null) return false;
return x.Equals(y);
}
public int GetHashCode(object x)
{
return x.GetHashCode();
}
public object DeepCopy(object value)
{
return value;
}
public object Replace(object original, object target, object owner)
{
return original;
}
public object Assemble(object cached, object owner)
{
return cached;
}
public object Disassemble(object value)
{
return value;
}
public override SqlType SqlType
{
get
{
return new SqlType(DbType.Int32);
}
}
public new SqlType[] SqlTypes
{
get { return new SqlType[] { SqlType }; }
}
public Type ReturnedType
{
get { return typeof(bool); }
}
public new void NullSafeSet(IDbCommand cmd, object value, int index)
{
var val = !((bool)value) ? 0 : 1;
NHibernateUtil.Int32.NullSafeSet(cmd, val, index);
}
public object NullSafeGet(IDataReader rs, string[] names, object owner)
{
return NHibernateUtil.Boolean.NullSafeGet(rs, names[0]);
}
public override void Set(IDbCommand cmd, object value, int index)
{
var val = !((bool)value) ? 0 : 1;
((IDataParameter)cmd.Parameters[index]).Value = val;
}
}
Mapping:
Property(x => x.IsDeleted, map => { map.NotNullable(true); map.Type<IntBoolUserType>(); });