-- connect sample/...drop table docs;
create table docs (
id number,
title varchar2(4000),
bfile_text bfile,
blob_text blob,
text1 char(1),
text2 char(1) );insert into docs ( id, title, bfile_text, blob_text ) values
( 1, 'a short essay', bfilename ( 'SAMPLE', 'Test.doc' ), empty_blob() );
commit;-- Populate the BLOB column with an exact copy of the BFILE columndeclare
v_length integer;
v_bfile_text bfile;
v_blob_text blob;
begin
select bfile_text, blob_text
into v_bfile_text, v_blob_text
from docs
where id = 1
for update;
v_length := Dbms_Lob.GetLength ( v_bfile_text ); Dbms_Lob.Open ( file_loc => v_bfile_text );
Dbms_Lob.LoadFromFile (
dest_lob => v_blob_text,
src_lob => v_bfile_text,
amount => v_length,
dest_offset => 1,
src_offset => 1 );
Dbms_Lob.Close ( file_loc => v_bfile_text ); update docs set blob_text = v_blob_text
where id = 1;
commit;
end;
/select
Dbms_Lob.GetLength ( bfile_text ) l_bfile,
Dbms_Lob.GetLength ( blob_text ) l_blob
from docs;-- both should be 19456 characters
create table docs (
id number,
title varchar2(4000),
bfile_text bfile,
blob_text blob,
text1 char(1),
text2 char(1) );insert into docs ( id, title, bfile_text, blob_text ) values
( 1, 'a short essay', bfilename ( 'SAMPLE', 'Test.doc' ), empty_blob() );
commit;-- Populate the BLOB column with an exact copy of the BFILE columndeclare
v_length integer;
v_bfile_text bfile;
v_blob_text blob;
begin
select bfile_text, blob_text
into v_bfile_text, v_blob_text
from docs
where id = 1
for update;
v_length := Dbms_Lob.GetLength ( v_bfile_text ); Dbms_Lob.Open ( file_loc => v_bfile_text );
Dbms_Lob.LoadFromFile (
dest_lob => v_blob_text,
src_lob => v_bfile_text,
amount => v_length,
dest_offset => 1,
src_offset => 1 );
Dbms_Lob.Close ( file_loc => v_bfile_text ); update docs set blob_text = v_blob_text
where id = 1;
commit;
end;
/select
Dbms_Lob.GetLength ( bfile_text ) l_bfile,
Dbms_Lob.GetLength ( blob_text ) l_blob
from docs;-- both should be 19456 characters
Oracle 8i数据库系统功能比前面版本更加完善,尤其是出现了BLOB,CLOB,NCLOB,
BFILE这些LOB(大型对象)类型来取代功能有限的LONG、LONGRAW类型。BLOB字段最
大长度为4G(4,294,967,295)字节,而且不再象LONGRAW那样每个表中只是限制有一
个字段是LONGRAW(最长2G)型的。BLOB,CLOB,NCLOB为内部BLOB(数据通常在数据
库中存放),BFILE为外部LOB(所存储的只是指向外部操作系统文件的指针),用户可
以使用PL/SQL的包DBMS_LOB来处理LOB数据,但是遗憾的是,DBMS_LOB包只能将二进
制操作系统文件写入到BLOB字段中,却无法将BLOB字段中的二进制操作系统文件取回
到操作系统中,估计将来会有所改善。本文将就如何在SQL*Plus将WORD文件存入取出
ORACLE中作详细解释说明,供各位同行参考。在internal这个用户下给scott用户授权如下:
SQL>grant create any directory to scott;
SQL>grant create any library to scott;
在scott这个用户下执行下述语句:SQL>create table bfile_tab (bfile_column BFILE);
SQL>create table utl_lob_test (blob_column BLOB);
SQL>create or replace directory utllobdir as 'C:\DDS\EXTPROC';
SQL>set serveroutput on然后执行下面语句就将C:\DDS\EXTPROC目录下的word文件COM.doc存入到utl_lob_test
表中的blob_column字段中了。declare
a_blob BLOB;
a_bfile BFILE := BFILENAME('UTLLOBDIR','COM.doc'); --用来指向外部操作系统文件
begin
insert into bfile_tab values (a_bfile)
returning bfile_column into a_bfile;
insert into utl_lob_test values (empty_blob())
returning blob_column into a_blob;
dbms_lob.fileopen(a_bfile);
dbms_lob.loadfromfile(a_blob, a_bfile, dbms_lob.getlength(a_bfile));
dbms_lob.fileclose(a_bfile);
commit;
end;
/
SQL>show errors
此时可以使用DBMS_LOB包的getlength这个procedure来检测是否已经将该word文件存入
到blob字段中了。如:
SQL> select dbms_lob.getlength(blob_column) from UTL_LOB_TEST;
结果如下:
DBMS_LOB.GETLENGTH(BLOB_COLUMN)
-------------------------------
83968
说明该word文件已经存入到blob字段中去了。