create directory utllobdir as 'd:'
create table blobtest(col1 BLOB);
create table clobtest(col1 cLOB);

--insert BLOB
declare
a_blob BLOB;
bfile_name BFILE := BFILENAME('UTLLOBDIR','teslob.doc');
begin
insert into blobtest values (empty_blob())
returning col1 into a_blob;
dbms_lob.fileopen(bfile_name);
dbms_lob.loadfromfile(a_blob, bfile_name, dbms_lob.getlength(bfile_name));
dbms_lob.fileclose(bfile_name);
commit;
end;

--update BLOB
declare
a_blob BLOB;
bfile_name BFILE := BFILENAME('UTLLOBDIR','log.txt');
begin
update blobtest set col1=empty_blob() where rownum=1
returning col1 into a_blob;
dbms_lob.fileopen(bfile_name);
dbms_lob.loadfromfile(a_blob, bfile_name, dbms_lob.getlength(bfile_name));
dbms_lob.fileclose(bfile_name);
commit;
end;

--insert CLOB
create table clobtest(col1 CLOB);

declare
a_clob CLOB;
bfile_name BFILE := BFILENAME('UTLLOBDIR','teslob.doc');
begin
insert into clobtest values (empty_clob())
returning col1 into a_clob;
dbms_lob.fileopen(bfile_name);
dbms_lob.loadfromfile(a_clob, bfile_name, dbms_lob.getlength(bfile_name));
dbms_lob.fileclose(bfile_name);
commit;
end;

--update CLOB
declare
a_clob CLOB;
bfile_name BFILE := BFILENAME('UTLLOBDIR','log.txt');
begin
update clobtest set col1=empty_clob() where rownum=1
returning col1 into a_clob;
dbms_lob.fileopen(bfile_name);
dbms_lob.loadfromfile(a_clob, bfile_name, dbms_lob.getlength(bfile_name));
dbms_lob.fileclose(bfile_name);
commit;
end;

通过查看lob字段的长度判断是否插入成功

select dbms_lob.getlength(col1) from blobtest;
select dbms_lob.getlength(col1) from clobtest;