NHibernate+Oracle 遇到ORA-01461和ORA-01084及解决方法

如果使用到Oracle的CLOB字段，那么NHibernate会遇到很诡异的“ORA-01461:仅可以插入LONG列的LONG值赋值”错误。关于此错误的分析和解决方法在这里(http://blog.csdn.net/pojianbing/archive/2008/08/09/2789426.aspx)有详细的介绍，实现NHibernate的自定义类型IUserType接口 ：

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public abstract class PatchForOracleLobField : IUserType {     public PatchForOracleLobField()     {     }     public bool IsMutable     {         get { return true; }     }     public System.Type ReturnedType     {         get { return typeof(String); }     }     public SqlType[] SqlTypes     {         get         {             return new SqlType[] { NHibernateUtil.String.SqlType };         }     }     public object DeepCopy(object value)     {         return value;     }     public new bool Equals(object x, object y)     {         return x == y;     }     public int GetHashCode(object x)     {         return x.GetHashCode();     }     public object Assemble(object cached, object owner)     {         return DeepCopy(cached);     }     public object Disassemble(object value)     {         return DeepCopy(value);     }     public object NullSafeGet(IDataReader rs, string[] names, object owner)     {         return NHibernate.NHibernateUtil.StringClob.NullSafeGet(rs, names[0]);     }     public abstract void NullSafeSet(IDbCommand cmd, object value, int index);     public object Replace(object original, object target, object owner)     {         return original;     } } public class OracleClobField : PatchForOracleLobField {     public override void NullSafeSet(IDbCommand cmd, object value, int index)     {         if (cmd is OracleCommand)         {             //CLob、NClob类型的字段，存入中文时参数的OracleDbType必须设置为OracleDbType.Clob             //否则会变成乱码（Oracle 10g client环境）             OracleParameter param = cmd.Parameters[index] as OracleParameter;             if (param != null)             {                 param.OracleType = OracleType.Clob;// 关键就这里啦                 param.IsNullable = true;             }         }         NHibernate.NHibernateUtil.StringClob.NullSafeSet(cmd, value, index);     } }

 

用此方法解决了CLOB字段2000-4000字的问题，可是今天又遇到了个新的“ORA-01084: OCI 调用中的参数无效”错误，google了一下，大概是说CLOB字段如果为null或’’时就会出这个错。

解决的办法:

将OracleClobField.NullSafeSet中的

if (cmd is OracleCommand) ….

改为

if ((cmd is OracleCommand) && !string.IsNullOrEmpty(value as string))

 

如果值是空或者空字符串的话就让NHibernate当默认的varchar2处理。

 

from:http://wuchang.cnblogs.com