oracle lob 数据类型应用实例

CREATE OR REPLACE
PROCEDURE "Pro_N_ROLES" ( V_Filter in varchar2 := ' ' )
is
    V_ROLE varchar2(30);
    V_TREEAUTH varchar2(4);
    V_ORI number(22);
    V_UPDATEFLAG varchar2(2); //子系统 标示字段
    v_Sql varchar2(4000);
    type vv
is
    ref cursor;
    CUR_DATA vv;
begin
    v_Sql := 'select 
ROLE,TREEAUTH,UPDATEFLAG
from ROLES@DB_N //创建好的 Dblink
where UPLOADFLAG = ''Y''' || V_Filter ; //子系统 标示字段，
    open CUR_DATA
    for v_Sql;
    loop
        fetch CUR_DATA into V_ROLE,V_TREEAUTH ,V_UPDATEFLAG;
        exit
    when CUR_DATA%NOTFOUND;
        if V_UPDATEFLAG = 'N' then
            begin
                INSERT
                INTO
                    J_ROLES
                    (
                        ROLE,
                        TREEAUTH,
                        SORI, //子系统www.111com.net主键值
                        S_FLAG //子系统标示
                    )
                    VALUES
                    (
                        V_ROLE,
                        V_TREEAUTH,
                        V_ORI, //A系统表主键值
                        'A系统'
                    )
                    ;
                commit;
                UPDATE
                    ROLES@DB_N
                    SET UPLOADFLAG = 'N',
                    UPDATEFLAG     = 'Y'
                WHERE
                    ORI = V_ORI;
                commit;
            end;
        end if;
        if V_UPDATEFLAG = 'Y' then
            begin
                UPDATE
                    J_ROLES
                    SET ROLE        = V_ROLE,
                    TREEAUTH    = V_TREEAUTH,
                    ORI     = V_ORI,
                    SORI = V_ORI,
                    S_FLAG   = 'A系统'
                WHERE
                    SORI   = V_ORI
                    and S_FLAG = 'A系统';
                commit;
                UPDATE
                    ROLES@DB_N
                    SET UPLOADFLAG = 'N',
                    UPDATEFLAG     = 'Y'
                WHERE
                    ORI = V_ORI;
                commit;
            end;
        end if;
//001这里加入更新CLOB字段代码
    end loop;
    close CUR_DATA;
end Pro_N_ROLES;

//先建立表 lob_example1
create table lob_example1(
id number(6) primary key,
name varchar2(10),
resume clob
);

//插入数据
insert into lob_example1 values(1,'猪',empty_clob());
insert into lob_example1 values(2,'狗',empty_clob());
commit;

//创建目录，保存在c盘根目录
CREATE OR REPLACE DIRECTORY DOCS AS 'C:';

//创建将文件内容写入数据库CLOB的存储过程
CREATE OR REPLACE PROCEDURE update_doc(
   t_id  number,
   filename varchar2
   )
as
   lobloc clob;
   fileloc bfile;
   amount int;
   src_offset int:=1;
   dest_offset int:=1;
   csid int:=0;
   lc  int:=0;
   warning int;
begin
   fileloc:=bfilename('DOCS',filename);
   dbms_lob.fileopen(fileloc,0);
   amount:=dbms_lob.getlength(fileloc);
   select resume into lobloc from lob_example1
     where id=t_id for update;
   dbms_lob.loadclobfromfile(lobloc,fileloc,amount,dest_offset,src_offset,csid,lc,warning);
   dbms_lob.fileclose(fileloc);
   commit;
end;

//调用存储过程,把文件读入数据库CLOB中，c盘下要有这两个文件
call update_doc(1,'aa.csv');
call update_doc(2,'bb.csv');

//察看id是2和1的行中文件大小
select length(resume) from lob_example1 where id=2;

select length(resume) from lob_example1 where id=1;

/////////////////////////////////////////////////////文件已经放入数据库

//将文件从数据库clob中读出来
CREATE OR REPLACE PROCEDURE get_doc(
   t_id  number,
   filename varchar2
   )
as
   lobloc clob;
   amount int;
   offset int:=1;
   buffer varchar2(2000);
   handle utl_file.file_type;
begin
   select resume into lobloc from lob_example1 where id=t_id;
   amount:=dbms_lob.getlength(lobloc);
   dbms_lob.read(lobloc,amount,offset,buffer);
   handle:=utl_file.fopen('DOCS',filename,'w',2000);
   utl_file.put_line(handle,buffer);
   utl_file.fclose(handle);
end;
/
 
//调用这个过程,把文件读出来
call get_doc(1,'zz.csv');