oracle raw device create tablespace

MsSQL,MySQL,Oracle,数据库连接字段

Ms sql 2000
drivername=com.microsoft.jdbc.sqlserver.SQLServerDriver
url=jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=books
username=sa
password=sa
MySQL
drivername=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost/books
username=root
password=root
Oracle
drivername=orac ......

Oracle常用语句

--如何用grade表的资料去更新usertable表的资料（有关联的字段userid）
update usertable u set u.grade =
(select g.grade from grade g where g.userid = u.userid);

--如何使查询结果字段生成序号
select rownum, t.* from sm_t_pad_new t
--如何快速做一个和原表一样的备份表
create ......

Oracle Waits event:DB File Scattered Read

The DB File Scattered Read wait event generally indicates waits related to full table scans or fast
full index scans. As full table scans are pulled into memory, they are scattered throughout the
buffer cache, since it is usually unlikely that they fall into contiguous buffers. A large numb ......

Oracle waits event:DB File Sequential Read

The DB File Sequential Read wait event generally indicates a single block read (an index read,
for example). A large number could indicate poor joining orders of tables or unselective indexing.
This number will certainly be large (normally) for a high-transaction, well-tuned system. You ......