对我来说算是挑战性的一个J2ME数据存储的问题,高手请进！

老猫的TOM 2010-12-31 11:13:09
一直在做J2EE的开发，最近公司拉了一个J2ME手持机<PDA>（其实和手机差不多）开发项目，本人算是第一次做这样的项目，如果问题问的有些弱还希望高手不要见笑。
下面开始说问题：
PAD使用的是WTK平台，要实现的功能是：对数据进行保存、修改、删除、查询，由于环境的问题，程序要求在无网络的情况下能够正常运行，所以运行环境算是单机版的。
数据格式很简单包含：档案ID、卡号、用户名、金额。
数据量最少在一万条以上，由于只能存储在本机环境内，这对于手持机来说不是件容易的事情。起先准备使用操作本地文本文件的方式存储（txt文件，每一行为一条数据）但是j2me对文本文件的操作真是太低级。对于查询和修改数据不易操作，而且数据过大会导致内存溢出。
所以本人准备尝试使用嵌入式数据库来完成，目前选用的数据库位JMESQL,网上对于这个数据库的操作知识并不是很多，只能在官方找到所谓的例子，可是操作中创建表一直不成功。后台打印异常为：
开始创建表----

..............false

开始创建表----

br.com.dreamsource.mobile.jmesql.exceptions.SQLException: already exists: PRICETABLE -- S0001 in statement [CREATE TABLE priceTable (   id int identity,    name varchar(20) not null,    percent float not null,   primary key(id))] -- Table

	at br.com.dreamsource.mobile.jmesql.jdbcResultSet.<init>(+37)

	at br.com.dreamsource.mobile.jmesql.jdbcConnection.executeStandalone(+19)

	at br.com.dreamsource.mobile.jmesql.jdbcConnection.execute(+21)

	at br.com.dreamsource.mobile.jmesql.jdbcStatement.fetchResult(+36)

	at br.com.dreamsource.mobile.jmesql.jdbcStatement.execute(+5)

	at com.sqlplus.FrameMainMIDlet.createDatabase(+48)

	at com.sqlplus.FrameMainMIDlet.commandAction(+33)

	at javax.microedition.lcdui.Display$DisplayAccessor.commandAction(+282)

	at javax.microedition.lcdui.Display$DisplayManagerImpl.commandAction(+10)

	at com.sun.midp.lcdui.DefaultEventHandler.commandEvent(+68)

	at com.sun.midp.lcdui.AutomatedEventHandler.commandEvent(+47)

	at com.sun.midp.lcdui.DefaultEventHandler$QueuedEventHandler.handleVmEvent(+186)

	at com.sun.midp.lcdui.DefaultEventHandler$QueuedEventHandler.run(+57)

看字面意思是提示数据表已存在，但是我明明是第一次创建。
附上源码希望高手能帮忙看看：



package com.sqlplus;



import java.util.Vector;



import javax.microedition.lcdui.Command;

import javax.microedition.lcdui.CommandListener;

import javax.microedition.lcdui.Display;

import javax.microedition.lcdui.Displayable;

import javax.microedition.lcdui.Form;

import javax.microedition.lcdui.TextField;

import javax.microedition.midlet.MIDlet;

import javax.microedition.midlet.MIDletStateChangeException;



import br.com.dreamsource.mobile.jmesql.jdbcConnection;

import br.com.dreamsource.mobile.jmesql.jdbcDriver;

import br.com.dreamsource.mobile.jmesql.jdbcPreparedStatement;

import br.com.dreamsource.mobile.jmesql.jdbcResultSet;

import br.com.dreamsource.mobile.jmesql.jdbcStatement;

import br.com.dreamsource.mobile.jmesql.exceptions.SQLException;





public class FrameMainMIDlet extends MIDlet implements CommandListener {



	private Form mainForm;

	



	private static DatabaseManager myDatabaseManager;

	private UserPOJO userPOJO;



	TextField tf = new TextField("要写入的数据", "", 100, TextField.ANY);



	TextField cx = new TextField("查询条件", "", 100, TextField.ANY);



	TextField cxjg = new TextField("查询结果", "", 100, TextField.ANY);



	Command a_cmdSet = new Command("添加", Command.SCREEN, 0);



	Command w_cmdSet = new Command("修改", Command.SCREEN, 0);



	Command r_cmdSet = new Command("查询", Command.SCREEN, 0);

	

	Command c_cmdSet = new Command("创建表", Command.SCREEN, 0);



	Command exitCommand = new Command("退出", Command.EXIT, 0);



	public FrameMainMIDlet() {



		mainForm = new Form("嵌入式数据库");

		mainForm.append(tf);

		mainForm.append(cx);

		mainForm.append(cxjg);

		mainForm.addCommand(exitCommand);

		mainForm.addCommand(c_cmdSet);

		mainForm.addCommand(r_cmdSet);

		mainForm.addCommand(w_cmdSet);

		mainForm.addCommand(a_cmdSet);

		mainForm.setCommandListener(this);



	}



/*	*//**

	 * 检查数据库如果没有开始创建

	 * 

	 * @return

	 * @throws Exception

	 */



      public  void createDatabase(UserPOJO userPOJO) {

	        jdbcDriver driver = new jdbcDriver();

	        

	      //  String userName = userPOJO.getUserName();

	       // String userPassword = userPOJO.getPasswd();

	        

	        userPOJO.setUserName("SA");

	        userPOJO.setPasswd("");

	        userPOJO.setDbName(Consts.DATABASE_NAME);

	        

	        jdbcConnection connection;

			try {

				connection = driver.connect(userPOJO.getAsProperties());

				  jdbcStatement statement = connection.createStatement();

			        boolean l=statement.execute(Consts.CREATE_PRICETABLE_TBL);

			        System.out.println(".............."+l);

			        if(l==true){

			        

			        	tf.setString("创建表成功.........");

			        	

			        	 boolean k=statement.execute("insert into priceTable values (null, 'tabela1', 10)");

			        	 if(k==true){

			        		 

			        		 cx.setString("插入数据成功.......");

			        		 

			        		 try {

			        			 

			        			   jdbcPreparedStatement prepared =connection.prepareStatement("select name from priceTable");

			        			   jdbcResultSet res = prepared.executeQuery();

			        				

			        				int i;

			        				StringBuffer Results = new StringBuffer();

			        				this.cxjg.setString("");

			        				System.out.println("数据查询"+Results);

			        				if (!(res == null)) {

			        					while (res.next()) {

			        						for (i = 1; i <= res.getColumnCount(); i++) {

			        							this.cxjg.setString(this.cxjg.getString()

			        									+ res.getColumnName(i) + " -- "

			        									+ res.getString(i) + "\n");

			        						}

			        						this.cxjg.setString(this.cxjg.getString());

			        					}

			        				}

			        			} catch (Exception e) {

			        				this.cxjg.setString(e.getMessage());

			        			}

			        	 }else{

			        		 

			        		 cx.setString("插入数据失败......."); 

			        		 

			        	 }

			        	

			        	

			        }else{

			        	

			        	tf.setString("创建表失败.....");

			        	

			        }

			       // boolean i=statement.execute(Consts.CREATE_CUSTOMER_TBL);

			       

			       

			} catch (SQLException e1) {

				// TODO 自动生成 catch 块

				e1.printStackTrace();

			}

	      

	    }



	protected void destroyApp(boolean arg0) throws MIDletStateChangeException {

		// TODO 自动生成方法存根



	}



	protected void pauseApp() {

		// TODO 自动生成方法存根



	}



	protected void startApp() throws MIDletStateChangeException {

		// TODO 自动生成方法存根

		

		

		

		    this.userPOJO = new UserPOJO();

	        this.userPOJO.setConnectionURL(Consts.DATABASE_CONNETION_STRING);

	        this.userPOJO.setDbName(Consts.DATABASE_NAME);

	        if (DatabaseManager.databaseExists(Consts.DATABASE_NAME)) {

	        	Display.getDisplay(this).setCurrent(mainForm);

	        } else {

	        	Display.getDisplay(this).setCurrent(mainForm);

	        }



	}



	public void commandAction(Command command, Displayable displayable) {

		if (command == r_cmdSet) {

			

			



			



		}else if(command==c_cmdSet){

			System.out.println("开始创建表----");

			try {

				createDatabase( userPOJO);

			} catch (Exception e) {

				// TODO 自动生成 catch 块

				e.printStackTrace();

			}

			

		}



	}



}





package com.sqlplus;



import br.com.dreamsource.mobile.jmesql.io.Properties;



public class UserPOJO {





    private String userName;

    private String passwd;

    private String dbName;

    private String connectionURL;

            

    public UserPOJO() {

    }



    public String getUserName() {

        return userName;

    }



    public void setUserName(String userName) {

        this.userName = userName;

    }



    public String getPasswd() {

        return passwd;

    }



    public void setPasswd(String passwd) {

        this.passwd = passwd;

    }



    public String getDbName() {

        return dbName;

    }



    public void setDbName(String dbName) {

        this.dbName = dbName;

    }

    

    public String getConnectionURL() {

        return connectionURL;

    }



    public void setConnectionURL(String connectionURL) {

        this.connectionURL = connectionURL;

    }

    

    public Properties getAsProperties() {

        Properties p = new Properties();

        p.setProperty("user", this.userName);

        p.setProperty("password", this.passwd);

        p.setProperty("database", this.dbName);

        return p;

    }



}
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Manfeel 2011-07-06
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兄弟，我最近也在研究jMeSQL，现在碰到一个更头痛的问题，用insert插入的记录，退出程序后，记录消失。
我查了一下jMeSQL的文档（如果那也算是文档的话！），可能是创建的table默认都在memeory中，于是用
Create cached table,结果，insert数据直接抛异常，我发现是在Cache.java代码中，里面估计是存在某些bug，找了很久也没有结果，我的QQ:179813134，希望交流
老猫的TOM 2011-01-12
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本人循环插入数据，貌似达到七千五百行左右报内存溢出。
老猫的TOM 2011-01-12
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问题已解决，不是代码问题，本人也不知为何数据表创建成功返回的boolea值却是false，会不会是javamesql的一个bug？
kazeik 2011-01-11
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对数据库不了解.
老猫的TOM 2011-01-04
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谢谢上面的两位，但本人感觉很孤独，有没有其他高手进来看看
老猫的TOM 2010-12-31
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package com.sqlplus;



public class Consts {



    public static final int UPDATE_TYPE_INSERT = 1;

    public static final int UPDATE_TYPE_UPDATE = 2;

    public static final int UPDATE_TYPE_DELETE = 3;

    

    public static final String DATABASE_NAME = "worders";

    public static final String DATABASE_CONNETION_STRING = "jdbc:mesqldb:worders";

    

    public static final String DROP_USER = "DROP USER ?";

    public static final String CREATE_USER = "CREATE USER ? PASSWORD ? admin";



    public static final String DROP_PRICTABLE_TBL = "DROP TABLE priceTable";

    public static final String CREATE_PRICETABLE_TBL = 

            "CREATE TABLE priceTable (" +

            "   id int identity, " +

            "   name varchar(20) not null, " +

            "   percent float not null," +

            "   primary key(id)" +

            ")";

    

    public static final String PRICETABLE_ID = "id";

    public static final String PRICETABLE_NAME = "name";

    public static final String PRICETABLE_PERCENT = "percent";

    

    public static final String PRICETABLE_SELECT_BY_EDIT = "SELECT * FROM pricetable";

    

    public static final String DROP_CUSTOMER_TBL = "DROP TABLE customer";

    public static final String CREATE_CUSTOMER_TBL = 

            "CREATE TABLE customer (" +

            "   id int identity," +

            "   remoteId int," +

            "   priceTableId  int," +

            "   dtRecord date," +

            "   name varchar(80) not null," +

            "   cpf varchar(11)," +

            "   cnpj varchar(14)," +

            "   phone varchar(10) not null," +

            "   fax varchar(10)," +

            "   contact varchar(80) not null," +

            "   mail varchar(80)," +

            "   zipCode varchar(8) not null," +

            "   credit float," +

            "   recordState int not null," +

            "   primary key(id)," +

            "   foreign key(priceTableId) references priceTable(id)" +

            ")";

    

    public static final String CUSTOMER_ID = "id"; 

    public static final String CUSTOMER_REMOTEID = "remoteid"; 

    public static final String CUSTOMER_PRICETABLEID = "pricetableid"; 

    public static final String CUSTOMER_DTRECORD = "dtrecord"; 

    public static final String CUSTOMER_NAME = "name"; 

    public static final String CUSTOMER_CPF = "cpf"; 

    public static final String CUSTOMER_CNPJ = "cnpj"; 

    public static final String CUSTOMER_PHONE = "phone"; 

    public static final String CUSTOMER_FAX = "fax"; 

    public static final String CUSTOMER_CONTACT = "contact"; 

    public static final String CUSTOMER_MAIL = "mail"; 

    public static final String CUSTOMER_ZIPCODE = "zipcode"; 

    public static final String CUSTOMER_CREDIT = "credit"; 

    public static final String CUSTOMER_RECORDSTATE = "recordstate"; 

    

    public static final String CUSTOMER_LOCATE_BY_FIELD = "SELECT id, name FROM customer";

    public static final String CUSTOMER_SELECT_BY_EDIT = 

            "SELECT priceTableId, name, cpf, cnpj, phone, fax, contact, mail, " +

            "zipCode, credit FROM customer";

    

    public static final String CUSTOMER_INSERT = 

            "INSERT INTO customer (remoteId, priceTableId, dtRecord, name, cpf, cnpj, phone, fax, " +

            "contact, mail, zipCode, credit, recordState) VALUES (0, ?, CURDATE(), ?, ?, ?, ?, ?, ?, ?, ?, ?, 0)";

    

    public static final String CUSTOMER_UPDATE = 

            "UPDATE customer set priceTableId = ?, name = ?, cpf = ?, cnpj = ?, phone = ?, fax = ?, " +

            "contact = ?, mail = ?, zipCode = ?, credit = ? where id = ?";

    

    public static final String CUSTOMER_DELETE = 

            "DELETE FROM customer where id = ?";

    

    

}


以上是我项目中的所有源码，如果大家对于存储还有其他什么好的方法或建议，麻烦能写出来参考一下，谢谢了。
softice_ 2010-12-31
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没搞过嵌入式数据库，帮顶
xiang1115 2010-12-31
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顶

我也正在研究jmesql，就是不知道怎么能创建表格。
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