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【DM版本】:8
【操作系统】：centos7.6
【CPU】:
【问题描述】*：

前提：DM的编码必须是UTF-8,不能修改

我在DM8数据库中创建了一个DBlink ; remote_db_link
我想把remote_db_link中DZJC20250403模式中COCT_CONTRACT
表的FFJ字段抽取成一个物化视图 FFJ是VARCHAR2(4000)类型的

在创建物化视图时：
CREATE MATERIALIZED VIEW COCT_CONTRACT
BUILD IMMEDIATE
REFRESH COMPLETE ON DEMAND
AS select
FFJ AS FFJ
from DZJC20250403.COCT_CONTRACT@remote_db_link;
提示[-7158]：远程操作符执行失败,错误详情[oracle column-level return code [1406]]

sql换成
CREATE MATERIALIZED VIEW COCT_CONTRACT
BUILD IMMEDIATE
REFRESH COMPLETE ON DEMAND
AS select
CAST(FFJ as VARCHAR(8000)) AS FFJ
from DZJC20250403.COCT_CONTRACT@remote_db_link;
会提示 [-7158]：远程操作符执行失败,错误详情[ORA-00910: specified length too long for its datatype]

换成
CREATE MATERIALIZED VIEW COCT_CONTRACT
BUILD IMMEDIATE
REFRESH COMPLETE ON DEMAND
AS select
CAST(FFJ AS TEXT) AS FFJ
from DZJC20250403.COCT_CONTRACT@remote_db_link;
提示[-7158]：远程操作符执行失败,错误详情[ORA-00902: invalid datatype]

换成
CREATE MATERIALIZED VIEW COCT_CONTRACT
BUILD IMMEDIATE
REFRESH COMPLETE ON DEMAND
AS select
CAST(FFJ AS CLOB) AS FFJ
from DZJC20250403.COCT_CONTRACT@remote_db_link;
提示 [-7158]：远程操作符执行失败,错误详情[ORA-00932: inconsistent datatypes: expected - got CLOB]

换成
CREATE MATERIALIZED VIEW COCT_CONTRACT
BUILD IMMEDIATE
REFRESH COMPLETE ON DEMAND
AS select
CAST(TO_BLOB(FFJ) AS CLOB) AS FFJ
from DZJC20250403.COCT_CONTRACT@remote_db_link;
提示 [-6147]：无效的十六进制数字

换成
CREATE MATERIALIZED VIEW COCT_CONTRACT
BUILD IMMEDIATE
REFRESH COMPLETE ON DEMAND
AS select
CAST(TO_BLOB(HEX(FFJ)) AS CLOB) AS FFJ
from DZJC20250403.COCT_CONTRACT@remote_db_link;

会提示[-7158]：远程操作符执行失败,错误详情[oracle column-level return code [1406]]

请问下我应该怎么操作才可以成功创建物化视图？？？