oracle增加、修改字段及属性

1.修改数据表名
ALTER TABLE [方案名.]OLD_TABLE_NAME RENAME TO NEW_TABLE_NAME;
2.修改列名
ALTER TABLE [方案名.]TABLE_NAME RENAME COLUMN OLD_COLUMN_NAME TO NEW_COLUMN_NAME;
3.修改列的数据类型
ALTER TABLE [方案名.]TABLE_NAME MODIFY COLUMN_NAME NEW_DATATYPE;
4.插入列
ALTER TABLE [方案名.]TABLE_NAME ADD COLUMN_NAME DATATYPE;
5.删除列
ALTER TABLE [方案名.]TABLE_NAME DROP COLUMN COLUMN_NAME;




（导出备份）exp username/pwd@cmisi file=/home/Oracle/test.dmp full=y;

更改数据库的连接数：
select count(*) from v$process;
select count(*) from v$session;
select value from v$parameter where name = 'processes';
alter system set processes=1000 scope=spfile;