android中的sqlite操作

package com.db.imgfornote;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class DBHelper extends SQLiteOpenHelper {
	final private static String mDbName="imgfornote";
	final private static int mDbVersion=1;
	private static DBHelper mInstance=null;
	private final static String mTUserPhoto="UserPhoto";
	final private static String mCreateSqlForNoteClass="create table if not exists NoteClass(classId integer primary key asc autoincrement,className NVARCHAR(100),rowTime timestamp default (datetime('now', 'localtime')))";
	final private static String mCreateSqlForUserPhoto="create table if not exists UserPhoto(photoId integer primary key asc autoincrement,photoName VARCHAR(200),userPt VARCHAR(200),title VARCHAR(255),classId integer,content NVARCHAR(250),tag NVARCHAR(200),remark text,status integer default 0,rowTime timestamp default (datetime('now', 'localtime')))";
	final private static String[] mInsertSqlForNoteClass={"insert into NoteClass(className) values('默认分类[私有]');","insert into NoteClass(className) values('读书笔记[私有]');","insert into NoteClass(className) values('电子资料[公开]');"};
	private DBHelper(Context context, CursorFactory factory) {
		super(context, mDbName, factory, mDbVersion);	
	}
	
	public static DBHelper GetInstance(Context context, SQLiteDatabase.CursorFactory factory)
	{
		if(mInstance==null){
			mInstance = new DBHelper(context,factory);	
		}
		return mInstance;
	}

	@Override
	public void onCreate(SQLiteDatabase db) {
		// 创建表
		db.execSQL(mCreateSqlForNoteClass);	
		db.execSQL(mCreateSqlForUserPhoto);
		//初始化数据
		for(int i=0;i<mInsertSqlForNoteClass.length;i++)
			db.execSQL(mInsertSqlForNoteClass[i]);
	}

	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		// TODO Auto-generated method stub

	}
	
	private Cursor ExecSQLForCursor(String sql, String[] selectionArgs){
		SQLiteDatabase db =getWritableDatabase();
		Log.i("ExecSQLForCursor",sql);
		return db.rawQuery(sql, selectionArgs);
	}
	private void ExecSQL(String sql){
		try{
			SQLiteDatabase db =getWritableDatabase();
			ExecSQL(sql,db);
		}catch(Exception e){
			Log.e("ExecSQL Exception",e.getMessage());
    	    		e.printStackTrace();
		}
	}
	private void ExecSQL(String sql,SQLiteDatabase db ){
	try{
			db.execSQL(sql);	
			Log.i("ExecSQL",sql);
		}catch(Exception e){
			Log.e("ExecSQL Exception",e.getMessage());
    	   		e.printStackTrace();
		}
	}
	//添加照片信息
	public long InsertUserPhoto(String photoName,String title){
		SQLiteDatabase db =getWritableDatabase();
		ContentValues cv = new ContentValues();
		cv.put("photoName", photoName);
		cv.put("title", title);
		return db.insert(mTUserPhoto, null, cv);
	}
	//查询照片信息
	public Cursor SearchPhoto(int row,String sort){
		Cursor cur = null;
		try{
			String ord = (sort==null|| sort.toLowerCase().startsWith("a"))?"asc":"desc";
			String sql = "select * from UserPhoto order by photoId "+ord;
			String[] args = {String.valueOf(row)};
			if(row>0){
				sql +=" limit ?";
			}else{
				args=null;
			}
			cur = ExecSQLForCursor(sql,args);			
		}catch (Exception e) {
			cur = null;
			Log.e("SearchPhoto Exception",e.getMessage());
    	    e.printStackTrace();
		}
		return cur;
	}	
	//修改照片信息
	public int UpdateUserPhoto(int photoId,int classId,String title,String content, String tag){
		SQLiteDatabase db =getWritableDatabase();
		ContentValues cv = new ContentValues();
		cv.put("classId", classId);
		cv.put("title", title);
		cv.put("content", content);
		cv.put("tag", tag);
		String[] args = {String.valueOf(photoId)};
		return db.update(mTUserPhoto, cv, "photoId=?",args);				
	}
	//删除照片信息
	public int DeleteUserPhoto(int photoId){
		SQLiteDatabase db =getWritableDatabase();
		String[] args = {String.valueOf(photoId)};
		return db.delete(mTUserPhoto, "photoId=?", args);
	}
}