Transaction tx = null;
try {
tx = (Transaction) session.beginTransaction();
Query q = null;
q = session.createQuery("From Cssb as cssb where cssb.flag=:FLAG ORDER BY cssb.czrkslsj desc");
q.setFirstResult(0);
q.setMaxResults(1000);
q.setString("FLAG", "000");
List objList = q.list();
int j = objList.size();
for (int i = 0; i < j; i++) {
     Cssb objCssb = (Cssb) objList.get(0);
     ....objCssb.getCzrkssssxq()
     ....all code only read the objCssb

     //i want mark a flag.
     objCssb.setFlag("abc");
     session.update(objCssb);
     session.flush();      //here i got a ORA-00932: inconsistent datatypes error
}
tx.commit();
} catch (Exception ex) {
tx.rollback();
ex.printStackTrace();
}

create table CSSB
(
  CHANGEID       VARCHAR2(30) not null,
  CZRKSSSSXQ     CHAR(6) not null,
  CZRKGMSFHM     CHAR(18) not null,
  CZRKXM         VARCHAR2(30) not null,
  CZRKXB         CHAR(1) not null,
  CZRKMZ         CHAR(2) not null,
  CZRKCSRQ       CHAR(8) not null,
  CZRKCSDGJ      CHAR(3),
  CZRKCSDSSX     CHAR(6),
  CZRKCSDXZ      VARCHAR2(40),
  CZRKJGGJ       CHAR(3),
  CZRKJGSSX      CHAR(6),
  CZRKJHRYHM     VARCHAR2(18),
  CZRKJHRYXM     VARCHAR2(30),
  CZRKJHRYGX     VARCHAR2(2),
  CZRKJHREHM     VARCHAR2(18),
  CZRKJHREXM     VARCHAR2(30),
  CZRKJHREGX     VARCHAR2(2),
  CZRKFQHM       VARCHAR2(18),
  CZRKFQXM       VARCHAR2(30),
  CZRKMQHM       VARCHAR2(18),
  CZRKMQXM       VARCHAR2(30),
  CZRKXX         CHAR(1),
  CZRKZZ         VARCHAR2(70) not null,
  CZRKCSDJLB     VARCHAR2(4) not null,
  CZRKCSZMBH     VARCHAR2(20),
  CZRKYWLX       VARCHAR2(2) not null,
  CZRKSLSJ       DATE not null,
  CZRKXZJDMC     VARCHAR2(40),
  CZRKXJGAJGMC   VARCHAR2(40) not null,
  CZRKXJGAJGJGDM CHAR(12) not null,
  CZRKPCSMC      VARCHAR2(40) not null,
  CZRKPCSJGDM    CHAR(12) not null,
  CZRKRYID       VARCHAR2(30) not null,
  FLAG           VARCHAR2(3) not null
)

<?xml version="1.0" encoding='UTF-8'?>
<!DOCTYPE hibernate-mapping PUBLIC
                            "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
                            "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >

<!-- DO NOT EDIT: This is a generated file that is synchronized -->
<!-- by MyEclipse Hibernate tool integration.                   -->
<!-- Created Thu Aug 18 11:36:21 CST 2005                         -->
<hibernate-mapping package="com.hibernate.senddatachange.pojo">

    <class name="Cssb" table="CSSB">
        <id name="changeid" column="CHANGEID" type="string">
            <generator class="assigned"/>
        </id>
        <property name="czrkssssxq" column="CZRKSSSSXQ" type="string"  not-null="true" />
        <property name="czrkgmsfhm" column="CZRKGMSFHM" type="string"  not-null="true" />
        <property name="czrkxm" column="CZRKXM" type="string"  not-null="true" />
        <property name="czrkxb" column="CZRKXB" type="string"  not-null="true" />
        <property name="czrkmz" column="CZRKMZ" type="string"  not-null="true" />
        <property name="czrkcsrq" column="CZRKCSRQ" type="string"  not-null="true" />
        <property name="czrkcsdgj" column="CZRKCSDGJ" type="string" />
        <property name="czrkcsdssx" column="CZRKCSDSSX" type="string" />
        <property name="czrkcsdxz" column="CZRKCSDXZ" type="string" />
        <property name="czrkjggj" column="CZRKJGGJ" type="string" />
        <property name="czrkjgssx" column="CZRKJGSSX" type="string" />
        <property name="czrkjhryhm" column="CZRKJHRYHM" type="string" />
        <property name="czrkjhryxm" column="CZRKJHRYXM" type="string" />
        <property name="czrkjhrygx" column="CZRKJHRYGX" type="string" />
        <property name="czrkjhrehm" column="CZRKJHREHM" type="string" />
        <property name="czrkjhrexm" column="CZRKJHREXM" type="string" />
        <property name="czrkjhregx" column="CZRKJHREGX" type="string" />
        <property name="czrkfqhm" column="CZRKFQHM" type="string" />
        <property name="czrkfqxm" column="CZRKFQXM" type="string" />
        <property name="czrkmqhm" column="CZRKMQHM" type="string" />
        <property name="czrkmqxm" column="CZRKMQXM" type="string" />
        <property name="czrkxx" column="CZRKXX" type="string" />
        <property name="czrkzz" column="CZRKZZ" type="string"  not-null="true" />
        <property name="czrkcsdjlb" column="CZRKCSDJLB" type="string"  not-null="true" />
        <property name="czrkcszmbh" column="CZRKCSZMBH" type="string" />
        <property name="czrkywlx" column="CZRKYWLX" type="string"  not-null="true" />
        <property name="czrkslsj" column="CZRKSLSJ" type="java.sql.Timestamp"  not-null="true" />
        <property name="czrkxzjdmc" column="CZRKXZJDMC" type="string" />
        <property name="czrkxjgajgmc" column="CZRKXJGAJGMC" type="string"  not-null="true" />
        <property name="czrkxjgajgjgdm" column="CZRKXJGAJGJGDM" type="string"  not-null="true" />
        <property name="czrkpcsmc" column="CZRKPCSMC" type="string"  not-null="true" />
        <property name="czrkpcsjgdm" column="CZRKPCSJGDM" type="string"  not-null="true" />
        <property name="czrkryid" column="CZRKRYID" type="string"  not-null="true" />
        <property name="flag" column="FLAG" type="string"  not-null="true" />
    </class>
   
</hibernate-mapping>