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c#oracle-databasehibernatenhibernatefluent-nhibernate
Felipe Oriani
Felipe Oriani

Reputation: 38638

Mapping a Long Type Column from Oracle to Nhibernate

I have a table in Oracle database with a column of Long type. In this column, we store a long text and we cannot change the type to CLob because there are other systems that use it as Long type. I am writting a new application to read this column and execute some tasks using NHibernate and Fluent NHibernate to map.

The mapping is ok, everything works except this column. When I read a entity from this table, the long column comes a string empty like "".

I have tried these:

Map(x => x.Query).Column("PNL_QUERY");

and

Map(x => x.Query).Column("PNL_QUERY").CustomType("StringClob");

and

Map(x => x.Query).Column("PNL_QUERY").CustomType("StringClob")
                                     .CustomSqlType("Long");

and

Map(x => x.Query).Column("PNL_QUERY").CustomType("Long");

and nothing works. All of them return "" in the Query field, when I load some entity from database.

How could I map this type of column in Oracle?

Thank you.

Upvotes: 2

Views: 1565

Answers (1)

Felipe Oriani
Felipe Oriani

Reputation: 38638

I found a solution:

To get the LONG columns working, in the ado.net oracle provider we have to set the OracleCommand.InitialLONGFetchSize property to -1. So we have to override the Oracle Driver from OracleDataClientDriver class. Something like this:

using NHibernate.Driver; using Oracle.DataAccess.Client;

namespace MyProject
{
    public class OracleDriverExtended : OracleDataClientDriver
    {
        public override void AdjustCommand(System.Data.IDbCommand command)
        {
            OracleCommand cmd = command as OracleCommand;
            if (cmd != null)
                cmd.InitialLONGFetchSize = -1;
        }
    }
}

And in the hibernate.cfg.xml set this custom driver to the connection.driver_class property:

<property name="connection.driver_class">
   MyProject.Data.OracleDriverExtended,
   MyProject
</property>

Now, NHibernate can read the LONG types from Oracle.

I found the solution here http://sonyarouje.com/2012/11/07/nhibernate-and-oracle-long-varchar-field/

Upvotes: 3

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