云数据库 GAUSSDB-DBE_LOB:示例

时间：2024-11-13 14:45:45

云数据库 GAUSSDB

示例

  
   
     
     
       --获取字符串的长度
SELECT DBE_LOB.GET_LENGTH('12345678');
 get_length 
------------
          8
(1 row)

-- DBE_LOB.READ接口示例
DECLARE
myraw  RAW(100);
amount INTEGER :=2;
buffer INTEGER :=1;
begin
DBE_LOB.READ('123456789012345',amount,buffer,myraw);
dbe_output.print_line(myraw);
end;
/
0123
ANONYMOUS BLOCK EXECUTE

CREATE TABLE blob_Table (t1 blob) DISTRIBUTE BY REPLICATION;
CREATE TABLE blob_Table_bak (t2 blob) DISTRIBUTE BY REPLICATION;
INSERT INTO blob_Table VALUES('abcdef');
INSERT INTO blob_Table_bak VALUES('22222');

-- DBE_LOB多接口示例
DECLARE
str varchar2(100) := 'abcdef';
source raw(100);
dest blob;
copyto blob;
amount int;
PSV_SQL varchar2(100);
PSV_SQL1 varchar2(100);
a int :=1;
len int;
BEGIN
source := dbe_raw.cast_from_varchar2_to_raw(str);
amount := dbe_raw.get_length(source);

PSV_SQL :='select * from blob_Table for update';
PSV_SQL1 := 'select * from blob_Table_bak for update';

EXECUTE IMMEDIATE PSV_SQL into dest;
EXECUTE IMMEDIATE PSV_SQL1 into copyto;

DBE_LOB.WRITE(dest, amount, 1, source);
DBE_LOB.WRITE_APPEND(dest, amount, source);

DBE_LOB.ERASE(dest, a, 1);
DBE_OUTPUT.PRINT_LINE(a);
DBE_LOB.COPY(copyto, dest, amount, 10, 1);
perform DBE_LOB.CLOSE(dest);
RETURN;
END;
/
1
ANONYMOUS BLOCK EXECUTE

--删除表
DROP TABLE blob_Table;
DROP TABLE blob_Table_bak;

      

    

  
 