自ORACLE 9i之后，Oracle提供了一个基于Web图形化数据管理工具Oracle企业管理器（Oracle Enterprise Manager），用来代替SQL命令来管理数据库。
Windows下OEM默认是开启的，可以直接访问，Linux下必须通过命令启动，相关命令如下：
--查看当前OEM状态
EMCTL STATUS DBCONSOLE；
--停止OEM
EMCTL STOP DBCONSOLE；
--启动OEM
EMCTL STRAT DBCONSOLE；
OEM的访问URL如下：
http://localhost:1158/em
如是本地访问则lcalhost本地服务的用户名，当远程访问OEM时则可输入远程服务器的IP地址。
在Linux下安装oracle后，Windows下访问OEM时会出现按钮中文乱码情况，解决方法如下：
1、停止OEM
[oracle@localhost ~]$ emctl stop dbconsole
TZ set to PRC
Oracle Enterprise Manager 10g DatabaseControl Release 10.2.0.1.0
Copyright (c) 1996, 2005 OracleCorporation. All rights reserved.
http://localhost.localdomain:1158/em/console/aboutApplication
Stopping Oracle Enterprise Manager 10gDatabase Control ...
... Stopped.
2、找到如下路径：
$ORACLE_HOME/jdk/jre/lib
$ORACLE_HOME/jre/1.4.2/lib
，执行下列步骤
[oracle@localhost ~]$ cd/opt/oracle/product/10.2.0/db_1/jdk/jre/lib/
[oracle@localhost lib]$ cp font.propertiesfont.properties.1.bat
[oracle@localhost lib]$ cp font.properties.zh_CN.Redhatfont.properties
[oracle@localhost lib]$ cd/opt/oracle/product/10.2.0/db_1/jre/1.4.2/lib/
[oracle@localhost lib]$ cp font.propertiesfont.properties.1.bat
[oracle@localhost lib]$ cpfont.properties.zh_CN.Redhat font.properties
此时可以查看文件font.properties最后一行如下
filename.-misc-zysong18030-medium-r-normal--*-%d-*-*-c-*-iso10646-1=/usr/share/fonts/zh_CN/TrueType/zysong.ttf
3、切换root用户查看是否存在文件/usr/share/fonts/zh_CN/TrueType/zysong.ttf，默认情况下是不存在此文件，如不存在，则可从Windows下C:/Windows/fonts找到中文字符文件，如不存在可用其他文件代替，替换文件名即可，推荐使用STSONG，处理结构如下所示：
[root@localhost ~]# cd/usr/share/fonts/zh_CN/TrueType/
[root@localhost TrueType]# ll
total 11440
-rwxrwxr-x 1 root root 11697600 Mar 8 13:53 zysong.ttf
需注意的是zysong.ttf文件名必须小写。
4、清楚OEM下的缓存图片
[oracle@localhost~]$cd/opt/oracle/product/10.2.0/db_1/oc4j/j2ee/oc4j_applications/applications/em/em/cabo/images/cache/zhs/
[oracle@localhost zhs]$ ll *.gif
-rw-r----- 1 oracle oinstall 1681 Mar 1211:07 b-0c_ASH_5.gif
-rw-r----- 1 oracle oinstall 1260 Mar 1210:05 b-3d-1.gif
-rw-r----- 1 oracle oinstall 1608 Mar 1210:05 b-61af-1.gif
……
[oracle@localhost zhs]$ rm *.gif
[oracle@localhost zhs]$ rm *.imx
5、重新启动OEM
[oracle@localhost zhs]$ emctl startdbconsole
TZ set to PRC
Oracle Enterprise Manager 10g DatabaseControl Release 10.2.0.1.0
Copyright (c) 1996, 2005 OracleCorporation. All rights reserved.
http://localhost.localdomain:1158/em/console/aboutApplication
Starting Oracle Enterprise Manager 10gDatabase Control ................................. started.
------------------------------------------------------------------
Logs are generated in directory/opt/oracle/product/10.2.0/db_1/localhost.localdomain_testdb/sysman/log
1、DBCollection的管理
package com.boonya.mongo;
import java.util.Set;
import com.mongodb.DBCollection;
public class CollectionManager {
public static DBCollection getDbCollection(String collectionName){
return DBConnection.getInstance().getCollection(collectionName.equals("")?"myCollection":collectionName);
}
public String getCollectionNames(){
String strNames="";
Set<String> colls =DBConnection.getInstance().getCollectionNames();
for (String cname : colls) {
strNames+=cname+",";
}
return strNames;
}
}
2、并发操作管理
package com.boonya.mongo;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBObject;
import com.mongodb.WriteConcern;
public class ConcurrencyManager {
private static DBCollection coll= CollectionManager.getDbCollection("myCollection");
/**
* If you want to ensure complete consistency in a “session” (maybe an http request),
* you would want the driver to use the same socket, which you can achieve by using a
* “consistent request”. Call requestStart() before your operations and requestDone()
* to release the connection back to the pool:
* DB and DBCollection are completely thread safe. In fact, they are cached so you get
* the same instance no matter what
*/
public void insertData(){
DB db=DBConnection.getInstance();
db.requestStart();
try {
db.requestEnsureConnection();
//do something
} finally {
db.requestDone();
}
}
/**
* Since by default a connection is given back to the pool after each request, you may
* wonder how calling getLastError() works after a write. You should actually use a
* write concern like WriteConcern.SAFE instead of calling getLastError() manually.
* The driver will then call getLastError() before putting the connection back in the pool.
*
* WriteConcern.NONE No exceptions thrown.
* WriteConcern.NORMAL Exceptions are only thrown when the primary node is unreachable for
* a read, or the full replica set is unreachable.
* WriteConcern.SAFE Same as the above, but exceptions thrown when there is a server error
* on writes or reads. Calls getLastError().
* WriteConcern.REPLICAS_SAFE Tries to write to two separate nodes. Same as the above, but
* will throw an exception if two writes are not possible.
* WriteConcern.FSYNC_SAFE Same as WriteConcern.SAFE, but also waits for write to be written to disk.
*
*/
public void writeConcern(){
coll.insert(new BasicDBObject("name","boonya").append("age", 21), WriteConcern.SAFE);
// is equivalent to
DB db=DBConnection.getInstance();
DBCollection coll=CollectionManager.getDbCollection("myCollection");
db.requestStart();
try {
coll.insert(new BasicDBObject("name","boonya").append("age", 21));
DBObject err = db.getLastError();
System.out.println(err);
} finally {
db.requestDone();
}
}
}
3、数据库管理
package com.boonya.mongo;
import java.net.UnknownHostException;
import com.mongodb.MongoClient;
public class DatabaseManager {
public String getDatabaseNames() throws UnknownHostException{
String strNames="";
MongoClient mongoClient;
mongoClient = new MongoClient();
for (String name : mongoClient.getDatabaseNames()) {
strNames+=name+",";
}
return strNames;
}
public void dropDatabase(String databaseName) throws UnknownHostException{
MongoClient mongoClient = new MongoClient();
mongoClient.dropDatabase(databaseName);
}
}
4、文档管理
package com.boonya.mongo;
import java.util.ArrayList;
import java.util.List;
import com.mongodb.BasicDBObject;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
public class DocumentManager {
private static DBCollection coll= CollectionManager.getDbCollection("myCollection");
public void insertADocument(){
BasicDBObject doc = new BasicDBObject("name", "MongoDB").append("type", "database")
.append("count", 1)
.append("info", new BasicDBObject("x", 203).append("y", 102));
coll.insert(doc);
}
/**
* PRINT BELOW:
* { "_id" : "49902cde5162504500b45c2c" ,
* "name" : "MongoDB" ,
* "type" : "database" ,
* "count" : 1 ,
* "info" : { "x" : 203 , "y" : 102}}
* @return
*/
public DBObject findTheFirstDocument(){
System.out.println("collection count:"+coll.getCount());
DBObject myDoc = coll.findOne();
System.out.println(myDoc);
return myDoc;
}
public List<DBObject> getADocumentsByCursor(){
List<DBObject> docs=new ArrayList<DBObject>();
DBCursor cursor =coll.find();
try {
while(cursor.hasNext()) {
DBObject obj=cursor.next();
System.out.println(obj);
docs.add(obj);
}
return docs;
} finally {
cursor.close();
}
}
/**
* PRINT LIKE THIS:
* { "_id" : "49903677516250c1008d624e" , "i" : 71 }
*/
public void queryADocument(){
BasicDBObject query = new BasicDBObject("i", 71);
DBCursor cursor =coll.find();
cursor = coll.find(query);
try {
while(cursor.hasNext()) {
System.out.println(cursor.next());
}
} finally {
cursor.close();
}
}
public void editQueryRegular(){
//db.things.find({j: {$ne: 3}, k: {$gt: 10} });
BasicDBObject query = new BasicDBObject("j", new BasicDBObject("$ne", 3)
.append("k", new BasicDBObject("$gt", 10)));
DBCursor cursor = coll.find(query);
try {
while(cursor.hasNext()) {
System.out.println(cursor.next());
}
} finally {
cursor.close();
}
}
public void getAsetDocument(){
BasicDBObject query = new BasicDBObject("i", new BasicDBObject("$gt", 50)); // e.g. find all where i > 50
// query = new BasicDBObject("i", new BasicDBObject("$gt", 20).
// append("$lte", 30)); // i.e. 20 < i <= 30
DBCursor cursor = coll.find(query);
try {
while(cursor.hasNext()) {
System.out.println(cursor.next());
}
} finally {
cursor.close();
}
}
}
5、索引管理
package com.boonya.mongo;
import java.util.List;
import com.mongodb.BasicDBObject;
import com.mongodb.DBCollection;
import com.mongodb.DBObject;
public class IndexManager {
private static DBCollection coll= CollectionManager.getDbCollection("myCollection");
public void createIndex(){
// create index on "i", ascending
coll.createIndex(new BasicDBObject("i", 1));
}
public List<DBObject> getIndexList(){
List<DBObject> list = coll.getIndexInfo();
for (DBObject o : list) {
System.out.println(o);
list.add(o);
}
return list;
}
}
6、预读取机制
package com.boonya.mongo;
import com.mongodb.BasicDBObject;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.ReadPreference;
public class ReadPreferences {
private static DBCollection coll= CollectionManager.getDbCollection("myCollection");
/**
* ReadPreference.primary();
* ReadPreference.primaryPreferred();
* ReadPreference.secondary();
* ReadPreference.secondaryPreferred();
* ReadPreference.nearest();
*/
public void read(){
DBObject query = new BasicDBObject("name", "simple doc");
//Read from primary if available, otherwise a secondary.
ReadPreference preference = ReadPreference.primaryPreferred();
DBCursor cur = new DBCursor(coll, query, (DBObject) preference);
//Read from any member node from the set of nodes which respond the fastest.
//The responsiveness of a node is measured with pings. Any node whose ping
//time is within 15 milliseconds of the node with the lowest ping time is considered near.
DBObject result =coll.findOne(query, (DBObject) ReadPreference.nearest());
// initialize a properly tagged read preference
ReadPreference tagged_pref =ReadPreference.secondaryPreferred(new BasicDBObject("datacenter", "Los Angeles"));
// include the tagged read preference in this request}}
DBObject result1=coll.findOne(new BasicDBObject("name", "simple doc"), (DBObject) tagged_pref);
// read from either LA or US_West
DBObject tagSetOne = new BasicDBObject("datacenter", "Los Angeles");
DBObject tagSetTwo = new BasicDBObject("region", "US_West");
ReadPreference pref =ReadPreference.primaryPreferred(tagSetOne, tagSetTwo);
}
}
1. 错误
操作系统和数据库都是服务提供商安装的，过了几个月才想起要用这个数据库，启动时出现如下错误。
ORA-00704: bootstrap process failure