PL/SQL 读写OS文件

24-1:建立directory
conn system/manager
CREATE DIRECTORY dir1 AS 'E:\DEMO';
GRANT READ,WRITE ON DIRECTORY EXP_DIR TO scott;

w：以文本方式写入OS文件；
a：以文本方式追加内容到OS文件；
wb：以字节方式写入OS文件；
ab：以字节方式追加内容到OS文件；
24-2:写入OS文件
CREATE OR REPLACE PROCEDURE add_emp_to_file(name VARCHAR2,filename VARCHAR2) IS
handle UTL_FILE.FILE_TYPE;
emp_record emp%ROWTYPE;
BEGIN
SELECT * INTO emp_record FROM emp WHERE LOWER(ename)=LOWER(name);
handle:=utl_file.fopen('EXP_DIR',filename,'a');
utl_file.put_line(handle,emp_record.ename||'    '
||emp_record.sal||'    '||emp_record.job);
utl_file.fclose(handle);
END;
/
exec add_emp_to_file('scott','emp.txt')
exec add_emp_to_file('smith','emp.txt')
exec add_emp_to_file('clark','emp.txt')

24-3:读取OS文件
CREATE TYPE info_table_type IS TABLE OF VARCHAR2(100);
/
CREATE OR REPLACE FUNCTION get_file_content(filename VARCHAR2) RETURN info_table_type IS
handle UTL_FILE.FILE_TYPE;
info_table info_table_type:=info_table_type('A');
f_exist BOOLEAN;
f_len INT;
blocksize INT;
i INT:=1;
BEGIN
utl_file.fgetattr('EXP_DIR',filename,f_exist,f_len,blocksize);
handle:=utl_file.fopen('EXP_DIR',filename,'r');
LOOP
utl_file.get_line(handle,info_table(i));
EXIT WHEN utl_file.fgetpos(handle)>=f_len;
info_table.extend;
i:=i+1;
END LOOP;
utl_file.fclose(handle);
RETURN info_table;
EXCEPTION
WHEN NO_DATA_FOUND THEN
RETURN info_table;
END;
/
DECLARE
info_table info_table_type:=info_table_type('A');
BEGIN
info_table.extend(&index-1);
info_table:=get_file_content('emp.txt');
FOR i IN 1..info_table.COUNT LOOP
dbms_output.put_line(info_table(i));
END LOOP;
END;
/