写入到blob字段的存储过程
写入到blob字段的存储过程
[sql] www.zzzyk.com
create or replace procedure write2blob(directions blob,
v_blob blob,
v_pos integer
)is
v_1time_maxlength integer; --一次读取的最大长度
amount integer; --总长度
v_blob_sub blob; --一次读取的长度
v_index integer; ---索引
v_sub_count integer;
offset integer;
directions2 blob;
begin
v_1time_maxlength := 32767; --允许的长度
amount := length(v_blob); --blob的总长度
v_sub_count := amount / v_1time_maxlength + 1; --分成子串的个数
v_index := 1; --索引从1开始
offset := v_pos;
directions2 := directions;
loop
dbms_output.put_line(length(v_blob));
DBMS_LOB.read(v_blob, v_1time_maxlength, offset, v_blob_sub); --读至v_blob_sub中
dbms_lob.writeappend(directions2, length(v_blob_sub), v_blob_sub); --将v_blob_sub中的内容写到字段中
v_index := v_index + 1;
offset := v_index * v_1time_maxlength + 1;
exit when v_index > v_sub_count;
end loop;
dbms_lob.close(directions2);
exception
when no_data_found then
dbms_output.put_line('找不到数据');
end;
测试代码：
[sql]
-- Created on 2013-3-8 by ZHANGXL
declare
-- Local variables here
i integer;
v_blob blob;
directions blob;
v_post_id number(18):=8814;
begin
select pt.post_text into v_blob from jforum_posts_text pt where pt.post_id=8817;
-- Test statements here
--execute updateblob(jforum_posts_text,post_id,post_text,8817,0,v_blob);
--update jforum_posts_text pt
-- set pt.post_text = EMPTY_BLOB()
-- where pt.post_id = v_post_id;
select pt.post_text into directions from jforum_posts_text pt where pt.post_id=v_post_id for update; --锁住
dbms_lob.open(directions, dbms_lob.lob_readwrite);--打开读写流
write2blob(directions,v_blob,1);
commit;
end;
表结构：
[sql]
-- Create table
create table JFORUM_POSTS_TEXT
(
POST_ID NUMBER(18) not null,
POST_TEXT BLOB,
POST_SUBJECT VARCHAR2(200),
ISDELETED NUMBER(1) default 0
)
tablespace XZFY
pctfree 10
initrans 1
maxtrans 255
storage
(
initial 128
minextents 1
maxextents unlimited
);
-- Create/Recreate primary, unique and foreign key constraints
alter table JFORUM_POSTS_TEXT
add primary key (POST_ID)
using index
tablespace XZFY
pctfree 10
initrans 2
maxtrans 255
storage
(
initial 64K
minextents 1
maxextents unlimited
);
