hibernate2与hibernate3区别及oracle

Hibernate3 的一些问题
 
做Hibernate第一个小例子就失败，原来是Hibernate2和Hibernate3的区别造成的
 
我用的是Hibernate3，而书上的例子、网上的例子全都是Hibernate2的，在网上的例子中｛Eclipse快速上手Hibernate（http://blog.youkuaiyun.com/javamxj/archive/2005/04/02/335076.aspx）｝提供的源代码，有如下两行：
import net.sf.hibernate.*;
import net.sf.hibernate.cfg.*;
搞了好几天，就是找不到 net.sf.hibernate.cfg 包，后来终于在优快云找到一篇文章，说明了Hibernate2升级为Hibernate3的注意事项，下面是原文：
================================
选择自 chinaewolf 的 Blog
hibernate2 升级为hibernate3的需要注意的事项
(chinaewolf的工作日记)
目的,主要是那当前的项目练手,熟悉一下hibernate2和hibernate3的差别,给当前项目一点扩展的空间.
1.首先将hibernate2.jar替换为hibernate3.jar(hibernate-3.0.5)
hibernate-tools.jar也替换成新的(从hibernate-tools-3.0.0.alpha4a找出来的)
2.将所有程序中的net.sf.hibernate替换为org.hibernate.
3.但是有例外
net.sf.hibernate.expression.Expression换为org.hibernate.criterion.Expression
如果用eclipse,用ctrl+shift+o快捷键可以加快速度:)
4.在使用hql查询时将
createSQLQuery(hql,"c",EZCampaignDTO.class);改为createSQLQuery(hql).addEntity("c",EZCampaignDTO.class);
5.在批量插入时
将原来的int size = ((SessionFactoryImpl)(session.getSessionFactory())).getJdbcBatchSize()
改为int size = ((SessionFactoryImpl)(session.getSessionFactory())).getSettings().getJdbcBatchSize();
6.在计算count时
将原来的int size = ((Integer) session.iterate(hql).next()).intValue();
改为int size = ((Integer) session.createQuery(hql).iterate().next()).intValue();
其中hql="select count(*) from " + DAOVar.contactClass;
7.还有就是把.hbm中的hibernate-mapping-2.0.dtd替换为hibernate-mapping-3.0.dtd
Hibernate Mapping DTD 2.0替换为Hibernate Mapping DTD 3.0
8.hibernate.cfg.xml中
Hibernate Mapping DTD 2.0替换为Hibernate Mapping DTD 3.0
org.hibernate.dialect.SQLServerDialect
9.hibernate.properties中类似
10.cache-config.xml中
替换为

11.classeshibernate.properties中
hibernate.cache.provider_class=org.hibernate.cache.EhCacheProvider
hibernate.dialect=org.hibernate.dialect.SQLServerDialect
晕s了,怎么这里还有
还是用编辑器暴力替换一下吧干脆
然后部署,集成测试,希望一切ok
结果咣铛,还是报错
12.在自动外部模块部分有一个功能是根据模版自动生成.hbm文件在load,结果出来的.hbm中有问题:
生成的 其中mapped="false" 出错.
找了半天才发现在网上的hibernate-mapping-3.0.dtd文件有支持mapped="false"这个属性.而本地的hebernate3.0.5中的
hibernate-mapping-3.0.dtd文件没有这个属性.晕,hibernate也太不负责了吧. 解决办法把hibernate-mapping-3.0.dtd
copy到jboss/bin目录下然后,在template文件中
然后他会在jboss/bin目录下读取该文件
13.重新测试,还是咣铛
发现子类读父类数据时抛出异常
"org.hibernate.LazyInitializationException: could not initialize proxy"
延迟抓取出的错,hb3对many-to-one的默认处理是lazy = "proxy"
没有搞懂到底怎么回事,把所有many-to-one,one-to-one都加上lazy="false"
再测试终于大功告成 
Oracle维护常用SQL语句
 
Oracle维护常用SQL语句       

用户评分:/5
差好
作者： Administrator 
2004-09-16 
1、查看表空间的名称及大小
select t.tablespace_name, round(sum(bytes/(1024*1024)),0) ts_size
from dba_tablespaces t, dba_data_files d
where t.tablespace_name = d.tablespace_name
group by t.tablespace_name;

2、查看表空间物理文件的名称及大小
select tablespace_name, file_id, file_name,
round(bytes/(1024*1024),0) total_space
from dba_data_files
order by tablespace_name;

3、查看回滚段名称及大小
select segment_name, tablespace_name, r.status,
(initial_extent/1024) InitialExtent,(next_extent/1024) NextExtent,
max_extents, v.curext CurExtent
From dba_rollback_segs r, v$rollstat v
Where r.segment_id = v.usn(+)
order by segment_name ;

4、查看控制文件
select name from v$controlfile;

5、查看日志文件
select member from v$logfile;

6、查看表空间的使用情况
select sum(bytes)/(1024*1024) as free_space,tablespace_name
from dba_free_space
group by tablespace_name;

SELECT A.TABLESPACE_NAME,A.BYTES TOTAL,B.BYTES USED, C.BYTES FREE,
(B.BYTES*100)/A.BYTES "% USED",(C.BYTES*100)/A.BYTES "% FREE"
FROM SYS.SM$TS_AVAIL A,SYS.SM$TS_USED B,SYS.SM$TS_FREE C
WHERE A.TABLESPACE_NAME=B.TABLESPACE_NAME AND A.TABLESPACE_NAME=C.TABLESPACE_NAME;

7、查看数据库库对象
select owner, object_type, status, count(*) count# from all_objects group by owner, object_type, status;

8、查看数据库的版本　
Select version FROM Product_component_version
Where SUBSTR(PRODUCT,1,6)='Oracle';

9、查看数据库的创建日期和归档方式
Select Created, Log_Mode, Log_Mode From V$Database;

10、捕捉运行很久的SQL
column username format a12
column opname format a16
column progress format a8

select username,sid,opname,
round(sofar*100 / totalwork,0) || '%' as progress,
time_remaining,sql_text
from v$session_longops , v$sql
where time_remaining <> 0
and sql_address = address
and sql_hash_value = hash_value
/

11、查看数据表的参数信息
SELECT partition_name, high_value, high_value_length, tablespace_name,
pct_free, pct_used, ini_trans, max_trans, initial_extent,
next_extent, min_extent, max_extent, pct_increase, FREELISTS,
freelist_groups, LOGGING, BUFFER_POOL, num_rows, blocks,
empty_blocks, avg_space, chain_cnt, avg_row_len, sample_size,
last_analyzed
FROM dba_tab_partitions
--WHERE table_name = :tname AND table_owner = :towner
ORDER BY partition_position

12、查看还没提交的事务
select * from v$locked_object;
select * from v$transaction;

13、查找object为哪些进程所用
select
p.spid,
s.sid,
s.serial# serial_num,
s.username user_name,
a.type object_type,
s.osuser os_user_name,
a.owner,
a.object object_name,
decode(sign(48 - command),
1,
to_char(command), 'Action Code #' || to_char(command) ) action,
p.program oracle_process,
s.terminal terminal,
s.program program,
s.status session_status
from v$session s, v$access a, v$process p
where s.paddr = p.addr and
s.type = 'USER' and
a.sid = s.sid and
a.object='SUBSCRIBER_ATTR'
order by s.username, s.osuser

14、回滚段查看
select rownum, sys.dba_rollback_segs.segment_name Name, v$rollstat.extents
Extents, v$rollstat.rssize Size_in_Bytes, v$rollstat.xacts XActs,
v$rollstat.gets Gets, v$rollstat.waits Waits, v$rollstat.writes Writes,
sys.dba_rollback_segs.status status from v$rollstat, sys.dba_rollback_segs,
v$rollname where v$rollname.name(+) = sys.dba_rollback_segs.segment_name and
v$rollstat.usn (+) = v$rollname.usn order by rownum

15、耗资源的进程（top session）
select s.schemaname schema_name, decode(sign(48 - command), 1,
to_char(command), 'Action Code #' || to_char(command) ) action, status
session_status, s.osuser os_user_name, s.sid, p.spid , s.serial# serial_num,
nvl(s.username, '[Oracle process]') user_name, s.terminal terminal,
s.program program, st.value criteria_value from v$sesstat st, v$session s , v$process p
where st.sid = s.sid and st.statistic# = to_number('38') and ('ALL' = 'ALL'
or s.status = 'ALL') and p.addr = s.paddr order by st.value desc, p.spid asc, s.username asc, s.osuser asc

16、查看锁（lock）情况
select /*+ RULE */ ls.osuser os_user_name, ls.username user_name,
decode(ls.type, 'RW', 'Row wait enqueue lock', 'TM', 'DML enqueue lock', 'TX',
'Transaction enqueue lock', 'UL', 'User supplied lock') lock_type,
o.object_name object, decode(ls.lmode, 1, null, 2, 'Row Share', 3,
'Row Exclusive', 4, 'Share', 5, 'Share Row Exclusive', 6, 'Exclusive', null)
lock_mode, o.owner, ls.sid, ls.serial# serial_num, ls.id1, ls.id2
from sys.dba_objects o, ( select s.osuser, s.username, l.type,
l.lmode, s.sid, s.serial#, l.id1, l.id2 from v$session s,
v$lock l where s.sid = l.sid ) ls where o.object_id = ls.id1 and o.owner
<> 'SYS' order by o.owner, o.object_name

17、查看等待（wait）情况
SELECT v$waitstat.class, v$waitstat.count count, SUM(v$sysstat.value) sum_value
FROM v$waitstat, v$sysstat WHERE v$sysstat.name IN ('db block gets',
'consistent gets') group by v$waitstat.class, v$waitstat.count

18、查看sga情况
SELECT NAME, BYTES FROM SYS.V_$SGASTAT ORDER BY NAME ASC

19、查看catched object
SELECT owner, name, db_link, namespace,
type, sharable_mem, loads, executions,
locks, pins, kept FROM v$db_object_cache

20、查看V$SQLAREA
SELECT SQL_TEXT, SHARABLE_MEM, PERSISTENT_MEM, RUNTIME_MEM, SORTS,
VERSION_COUNT, LOADED_VERSIONS, OPEN_VERSIONS, USERS_OPENING, EXECUTIONS,
USERS_EXECUTING, LOADS, FIRST_LOAD_TIME, INVALIDATIONS, PARSE_CALLS, DISK_READS,
BUFFER_GETS, ROWS_PROCESSED FROM V$SQLAREA

21、查看object分类数量
select decode (o.type#,1,'INDEX' , 2,'TABLE' , 3 , 'CLUSTER' , 4, 'VIEW' , 5 ,
'SYNONYM' , 6 , 'SEQUENCE' , 'OTHER' ) object_type , count(*) quantity from
sys.obj$ o where o.type# > 1 group by decode (o.type#,1,'INDEX' , 2,'TABLE' , 3
, 'CLUSTER' , 4, 'VIEW' , 5 , 'SYNONYM' , 6 , 'SEQUENCE' , 'OTHER' ) union select
'COLUMN' , count(*) from sys.col$ union select 'DB LINK' , count(*) from

22、按用户查看object种类
select u.name schema, sum(decode(o.type#, 1, 1, NULL)) indexes,
sum(decode(o.type#, 2, 1, NULL)) tables, sum(decode(o.type#, 3, 1, NULL))
clusters, sum(decode(o.type#, 4, 1, NULL)) views, sum(decode(o.type#, 5, 1,
NULL)) synonyms, sum(decode(o.type#, 6, 1, NULL)) sequences,
sum(decode(o.type#, 1, NULL, 2, NULL, 3, NULL, 4, NULL, 5, NULL, 6, NULL, 1))
others from sys.obj$ o, sys.user$ u where o.type# >= 1 and u.user# =
o.owner# and u.name <> 'PUBLIC' group by u.name order by
sys.link$ union select 'CONSTRAINT' , count(*) from sys.con$

23、有关connection的相关信息
1）查看有哪些用户连接
select s.osuser os_user_name, decode(sign(48 - command), 1, to_char(command),
'Action Code #' || to_char(command) ) action, p.program oracle_process,
status session_status, s.terminal terminal, s.program program,
s.username user_name, s.fixed_table_sequence activity_meter, '' query,
0 memory, 0 max_memory, 0 cpu_usage, s.sid, s.serial# serial_num
from v$session s, v$process p where s.paddr=p.addr and s.type = 'USER'
order by s.username, s.osuser
2）根据v.sid查看对应连接的资源占用等情况
select n.name,
v.value,
n.class,
n.statistic#
from v$statname n,
v$sesstat v
where v.sid = 71 and
v.statistic# = n.statistic#
order by n.class, n.statistic#
3）根据sid查看对应连接正在运行的sql
select /*+ PUSH_SUBQ */
command_type,
sql_text,
sharable_mem,
persistent_mem,
runtime_mem,
sorts,
version_count,
loaded_versions,
open_versions,
users_opening,
executions,
users_executing,
loads,
first_load_time,
invalidations,
parse_calls,
disk_reads,
buffer_gets,
rows_processed,
sysdate start_time,
sysdate finish_time,
'>' || address sql_address,
'N' status
from v$sqlarea
where address = (select sql_address from v$session where sid = 71)

24、查询表空间使用情况select a.tablespace_name "表空间名称",
100-round((nvl(b.bytes_free,0)/a.bytes_alloc)*100,2) "占用率(%)",
round(a.bytes_alloc/1024/1024,2) "容量(M)",
round(nvl(b.bytes_free,0)/1024/1024,2) "空闲(M)",
round((a.bytes_alloc-nvl(b.bytes_free,0))/1024/1024,2) "使用(M)",
Largest "最大扩展段(M)",
to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') "采样时间"
from (select f.tablespace_name,
sum(f.bytes) bytes_alloc,
sum(decode(f.autoextensible,'YES',f.maxbytes,'NO',f.bytes)) maxbytes
from dba_data_files f
group by tablespace_name) a,
(select f.tablespace_name,
sum(f.bytes) bytes_free
from dba_free_space f
group by tablespace_name) b,
(select round(max(ff.length)*16/1024,2) Largest,
ts.name tablespace_name
from sys.fet$ ff, sys.file$ tf,sys.ts$ ts
where ts.ts#=ff.ts# and ff.file#=tf.relfile# and ts.ts#=tf.ts#
group by ts.name, tf.blocks) c
where a.tablespace_name = b.tablespace_name and a.tablespace_name = c.tablespace_name

25、 查询表空间的碎片程度
select tablespace_name,count(tablespace_name) from dba_free_space group by tablespace_name
having count(tablespace_name)>10;

alter tablespace name coalesce;
alter table name deallocate unused;

create or replace view ts_blocks_v as
select tablespace_name,block_id,bytes,blocks,'free space' segment_name from dba_free_space
union all
select tablespace_name,block_id,bytes,blocks,segment_name from dba_extents;

select * from ts_blocks_v;

select tablespace_name,sum(bytes),max(bytes),count(block_id) from dba_free_space
group by tablespace_name;