antroid数据库操作

1、创建数据库和升级数据库

 package org.jgw.service;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;

public class DBOpenHelper extends SQLiteOpenHelper {

    public DBOpenHelper(Context context) 
    {
        super(context, "mxh.db", null, 2); 
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table test(id integer primary key autoincrement,name varchar(20))");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        db.execSQL("alter table test add memo varchar(50)");
    }

}

2、数据库的添加、删除、修改、查询

 package org.jgw.service;

import java.util.ArrayList;
import java.util.List;

import org.jgw.entity.testTable;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

public class testTableService 
{
    
    DBOpenHelper dbop;
    SQLiteDatabase db;
    
    public testTableService(Context context) {
        dbop=new DBOpenHelper(context);        
    }

    public void add(testTable t)
    {
        db=dbop.getWritableDatabase();
        db.execSQL("insert into test(name,memo) values(?,?)",new Object[]{t.getName(),t.getMemo()});        
    }
    
    public void delete(Integer id)
    {
        db=dbop.getWritableDatabase();
        db.execSQL("delete from test where id=?",new Object[]{id});            
    }
    
    public void update(testTable t)
    {
        db=dbop.getWritableDatabase();
        db.execSQL("update test set name=?,memo=? where id=?",new Object[]{t.getName(),t.getMemo(),t.getId()});
    }
    
    public testTable find(Integer id)
    {
        testTable test;
        db=dbop.getWritableDatabase();
        Cursor cursor=db.rawQuery("select * from test where id=?",new String[]{id.toString()});
        if(cursor.moveToFirst())
        {
            test=new testTable(cursor.getInt(cursor.getColumnIndex("id")), cursor.getString(cursor.getColumnIndex("name")), cursor.getString(cursor.getColumnIndex("memo")));
            cursor.close();
            return test;
        }        
        cursor.close();
        return null;
    }
    
    public List<testTable> findSplitPage(int offset,int pagesize,String where)
    {
        testTable test;
        List<testTable> list=new ArrayList<testTable>();
        db=dbop.getWritableDatabase();
        Cursor cursor=db.rawQuery("select * from test "+where+" order by id limit ?,?",new String[]{offset+"",pagesize+""});
        while(cursor.moveToNext())
        {
            String name=cursor.getString(cursor.getColumnIndex("name"));
            String memo=cursor.getString(cursor.getColumnIndex("memo"));
            test= new testTable(name, memo);
            list.add(test);
        }
        cursor.close();
        return list;
    }
    
    public int getSumCount()
    {        
        db=dbop.getWritableDatabase();
        Cursor cursor=db.rawQuery("select count(*) from test",null);
        cursor.moveToFirst();
        return cursor.getInt(0);
    }
    
    /*
     * 事务的使用
     */
    public void Transaction()
    {
        db=dbop.getWritableDatabase();
        db.beginTransaction();
        try
        {
            db.execSQL("update test set name=? where id=?",new Object[]{"sdfsdf","1"});
            db.execSQL("update test set name=?  where id=?",new Object[]{"aaaa","2"});
            db.setTransactionSuccessful();
        }
        finally
        {
            db.endTransaction();
        }
    }
    
}

3、数据库实务操作 

  /*

     * 事务的使用
     */
    public void Transaction()
    {
        db=dbop.getWritableDatabase();
        db.beginTransaction();
        try
        {
            db.execSQL("update test set name=? where id=?",new Object[]{"sdfsdf","1"});
            db.execSQL("update test set name=?  where id=?",new Object[]{"aaaa","2"});
            db.setTransactionSuccessful();
        }
        finally
        {
            db.endTransaction();
        }
    }