Android SQLiteDatabase的使用

package com.shawn.test;

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

public class DatabaseAdapter{

	private static final String DB_NAME = "Test.db";	//数据库名
	private static final int 	DB_VERSION = 1;			//数据库版本
	
	private static final String DB_TABLE = "my_order";	//表名
	private static final String KEY_ID = "_id";			//id
	private static final String KEY_ORDER_ID = "order_id";	//订单号
	private static final String KEY_TYPE = "_type";			//订单类型
	private static final String KEY_STATE = "_state";		//订单状态
	
	private Context context;
	private DatabaseHelper mDatabaseHelper;
	private SQLiteDatabase mSQLiteDatabase;
	
	private static class DatabaseHelper extends SQLiteOpenHelper{
		//创建数据库语句
		private static final String DB_CREAT = "CREATE TABLE "
				+ DB_TABLE
				+ " (" + KEY_ID + " INTEGER PRIMARY KEY,"
				+ KEY_ORDER_ID + " TEXT,"
				+ KEY_TYPE + " INTEGER,"
				+ KEY_STATE + " INTEGER)";
		
		public DatabaseHelper(Context context) {
			super(context, DB_NAME,  null , DB_VERSION);
		}
		@Override
		public void onCreate(SQLiteDatabase db) {
			// TODO Auto-generated method stub
			db.execSQL(DB_CREAT);
		}
		@Override
		public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
			// TODO Auto-generated method stub
			db.execSQL("DROP TABLE IF EXISTS "+DB_TABLE);
			onCreate(db);
		}
	}

	public DatabaseAdapter(Context context) {
		this.context = context;
	}
	//开启
	public void open() {
		mDatabaseHelper = new DatabaseHelper(context);  
        mSQLiteDatabase = mDatabaseHelper.getWritableDatabase();
	}
	//关闭
	public void close() { 
		mSQLiteDatabase.close();
		mDatabaseHelper.close();
	}
	
	//增
	public long insertData(String orderId, int type) {  
		ContentValues values = new  ContentValues();   
		values.put(KEY_ORDER_ID, orderId); 
		values.put(KEY_TYPE, type);
		values.put(KEY_STATE, Config.STATE_APPLY); 
		long id = mSQLiteDatabase.insert(DB_TABLE, KEY_ID, values); 
		return id;
	}
	//删
	public boolean deleteData(Context context, long id) {
		boolean delete = mSQLiteDatabase.delete(DB_TABLE, KEY_ID + "=" +id, null)>0;
		return delete;
	}
	//改
	public boolean updateData(long id, int state) {
		ContentValues values = new  ContentValues();  
		values.put(KEY_STATE, ""+state); 
		boolean update = mSQLiteDatabase.update(DB_TABLE, values, KEY_ID + "=" +id, null)>0;
		return update;
	}
	//查
	public Cursor fetchData(String selection) {
		Cursor mCursor = mSQLiteDatabase.query(DB_TABLE, new String[]{KEY_ID, KEY_ORDER_ID, KEY_TYPE, KEY_STATE}, selection, null, null, null, null);
		if(mCursor != null)
			mCursor.moveToFirst();
		return mCursor;
	}
}