数据库一无所知，最近用到，百度+问群，刚刚入门，自己总结一下做个笔记：

1，创建数据库：继承SQLiteOpenHelper

public class DatabaseHelper extends SQLiteOpenHelper {

	private String Tag = "DatabaseHelper";

	public DatabaseHelper(Context context, String name,
			CursorFactory factory, int version) {
		super(context, name, factory, version);
		// TODO Auto-generated constructor stub
	}

	@Override
	public void onCreate(SQLiteDatabase db) {
		// TODO Auto-generated method stub
		LogUtils.i(Tag, "onCreate");
		try {
			//本机处理操作同步到云端后的记录
			db.execSQL("CREATE TABLE devicesOperation_tb (" 
					+ "directory VARCHAR (50)  NOT NULL," 
					+ "rootDir VARCHAR (20)  NOT NULL," 
					+ "parentDir VARCHAR (20)  NOT NULL,"
					+ "fileName VARCHAR (50)  NOT NULL,"
					+ "time VARCHAR (50)  NOT NULL" 
					+ ");");

			//本机所有文件记录，用于和操作后的对比，devicesFile_tb记录没有，devicesOperation_tb记录有的话，则是删除操作
			db.execSQL("CREATE TABLE devicesFile_tb (" 
					+ "directory VARCHAR (50)  NOT NULL," 
					+ "rootDir VARCHAR (20)  NOT NULL," 
					+ "parentDir VARCHAR (20)  NOT NULL,"
					+ "fileName VARCHAR (50)  NOT NULL,"
					+ "time VARCHAR (50)  NOT NULL" 
					+ ");");

			//云端操作记录表
			db.execSQL("CREATE TABLE serverOperation_tb (" 
					+ "fileName VARCHAR (50)  NOT NULL," 
					+ "rootDir VARCHAR (20)  NOT NULL," 
					+ "parentDir VARCHAR (20)  NOT NULL," 
					+ "operation VARCHAR (10)  NOT NULL," 
					+ "filePath VARCHAR (100)" 
					+ ");");


		} catch (Exception e) {
			// TODO: handle exception
			LogUtils.i(Tag, "onCreate:"+e);
		}
	}

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

	}

}

db.execSQL("CREATE TABLE devicesOperation_tb (" 
					+ "directory VARCHAR (50)  NOT NULL," 
					+ "rootDir VARCHAR (20)  NOT NULL," 
					+ "parentDir VARCHAR (20)  NOT NULL,"
					+ "fileName VARCHAR (50)  NOT NULL,"
					+ "time VARCHAR (50)  NOT NULL" 
					+ ");");

这一句是创建数据库， devicesOperation_tb：表名；后面都是字段名，每一句以“，”逗号结束，最后一句不用

2，获取执行创建数据库，得到数据库：

	mDatabaseHelper = new DatabaseHelper(mContext, DATABASE_NAME, null, 1);	
	mSqLiteDatabase = mDatabaseHelper.getReadableDatabase();

只new是得不到数据库的，必须要get ReadableDatabase()或者getWriteableDatabase()一下才能看到数据库，这句执行后，就可以在data/data/你的项目包名/databases下面看到有一个 devicesOperation_tb.db的数据库了

3，数据库添加数据，也就是insert语句：

ContentValues cv = new ContentValues();
cv.put(DevicesOperationTB.directory, f.toString());
cv.put(DevicesOperationTB.rootDir, FilePath.split("/")[0]);
cv.put(DevicesOperationTB.parentDir, FilePath.split("/")[1]);
cv.put(DevicesOperationTB.fileName, FilePath.split("/")[2]);
mSqLiteDatabase.insert(DevicesFileTB.devicesFile_tb, null, cv);