oracleDBMSOUTPUT包学习.docVIP

DBMS_OUTPUT包学习虽然一直在使用DBMS_OUTPUT.PUT_LINE，但是说实话没有仔细研究过DBMS_OUTPUT包中的其他方法和函数的用法，所以这次特地来研究一下。 先简单的讲解一下这个包的所有procedure的含义及作用： ----------------------- ??? 1、enable：在serveroutput on的情况下，用来使dbms_output生效(默认即打开) ??? 2、disable：在serveroutput on的情况下，用来使dbms_output失效 ??? 3、put：将内容写到内存，等到put_line时一起输出 ??? 4、put_line：不用多说了，输出字符 ??? 5、new_line：作为一行的结束，可以理解为写入buffer时的换行符 ??? 6、get_line：获取没有输出的buffer中的信息 ??? 7、get_lines：以数组形式来获取所有buffer中的信息 ??? 需要注意以下几点： ----------------------- ??? 1、set serveroutput on：如果要在sqlplus中看到dbms_output的输出，则必须设置该参数值为on ??? 2、每行能容纳的最大值是32767bytes ??? 3、buffer的默认值是20000bytes，可设置的最小值为2000bytes，最大值为1000000bytes ??? 来看一下Package中自带的说明： ----------------------- create or replace package sys.dbms_output as -- DE-HEAD???? - tell SED where to cut when generating fixed package -------------- OVERVIEW---- These procedures accumulate information in a buffer (via put and-- put_line) so that it can be retrieved out later (via get_line or-- get_lines). If this package is disabled then all-- calls to this package are simply ignored. This way, these routines-- are only active when the client is one that is able to deal with the-- information. This is good for debugging, or SPs that want to want-- to display messages or reports to sql*dba or plus (like describing-- procedures, etc.). The default buffer size is 20000 bytes. The-- minimum is 2000 and the maximum is 1,000,000. ------------- EXAMPLE---- A trigger might want to print out some debugging information. To do-- do this the trigger would do--??? dbms_output.put_line(I got here:||:new.col|| is the new value);-- If the client had enabled the dbms_output package then this put_line-- would be buffered and the client could, after executing the statement-- (presumably some insert, delete or update that caused the trigger to-- fire) execute--??? begin dbms_output.get_line(:buffer, :status); end;-- to get the line of information back. It could then display the-- buffer on the screen. The c