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[精彩] 如何用sql把一个字段从long raw类型改为blob类型???

 执着男孩 2006-08-26

请教各位 数据库的高手。一个字段原来是long raw类型的,现在要把它改成blob类型,但是原来的纪录都要保留。不知道这两种类型用sql文怎么转换。

请执教!!![color=red][/color]



 chaoping 回复于:2003-02-22 19:23:43

看看这个例子:

SQL>; select count(*) from sys.IDL_UB1$;

  COUNT(*)
----------
      4003

SQL>; desc sys.IDL_UB1$
 Name                                                                                                              Null?    Type
 ----------------------------------------------------------------------------------------------------------------- -------- ----------------------------------------------------------------------------
 OBJ#                                                                                                              NOT NULL NUMBER
 PART                                                                                                              NOT NULL NUMBER
 VERSION                                                                                                                    NUMBER
 PIECE#                                                                                                            NOT NULL NUMBER
 LENGTH                                                                                                            NOT NULL NUMBER
 PIECE                                                                                                             NOT NULL LONG RAW

SQL>; create table system.rawtolob(obj,part,version,piece#,length,piece)
  2  as
  3  select obj#,part,version,piece#,length,to_lob(piece) from sys.idl_ub1$;

Table created.

SQL>; select count(*) from rawtolob;

  COUNT(*)
----------
      4003

SQL>; desc rawtolob
 Name                                                                                                              Null?    Type
 ----------------------------------------------------------------------------------------------------------------- -------- ----------------------------------------------------------------------------
 OBJ                                                                                                               NOT NULL NUMBER
 PART                                                                                                              NOT NULL NUMBER
 VERSION                                                                                                                    NUMBER
 PIECE#                                                                                                            NOT NULL NUMBER
 LENGTH                                                                                                            NOT NULL NUMBER
 PIECE                                                                                                                      BLOB





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