android中操纵sqlite数据库

import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;public class DBOpenHelper extends SQLiteOpenHelper {private static final int VERSION = 1;// 定义数据库版本号private static final String DBNAME = "account.db";// 定义数据库名public DBOpenHelper(Context context){// 定义构造函数super(context, DBNAME, null, VERSION);// 重写基类的构造函数}///public abstract void onCreate(SQLiteDatabase db)Called when the database is created for the first time. @Overridepublic void onCreate(SQLiteDatabase db){// 创建数据库db.execSQL("create table tb_outaccount (_id integer primary key,money decimal,time varchar(10),"+ "type varchar(10),address varchar(100),mark varchar(200))");// 创建支出信息表db.execSQL("create table tb_inaccount (_id integer primary key,money decimal,time varchar(10),"+ "type varchar(10),handler varchar(100),mark varchar(200))");// 创建收入信息表db.execSQL("create table tb_pwd (password varchar(20))");// 创建密码表db.execSQL("create table tb_flag (_id integer primary key,flag varchar(200))");// 创建便签信息表}///public abstract void onUpgrade(SQLiteDatabase db,//    int oldVersion,//    int newVersion)Called when the database needs to be upgraded. //@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)// 覆写基类的onUpgrade方法，以便数据库版本更新{}//////////}

import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import com.xiaoke.accountsoft.model.*;public class PwdDAO {private DBOpenHelper helper;// 创建DBOpenHelper对象private SQLiteDatabase db;// 创建SQLiteDatabase对象public PwdDAO(Context context)// 定义构造函数{helper = new DBOpenHelper(context);// 初始化DBOpenHelper对象}/** * 添加密码信息 *  * @param tb_pwd */public void add(Tb_pwd tb_pwd) {/// SQLiteDatabase getWritableDatabase()       //  Create and/or open a database that will be used for reading and writing. db = helper.getWritableDatabase();// 初始化SQLiteDatabase对象// 执行添加密码操作db.execSQL("insert into tb_pwd (password) values (?)",new Object[] { tb_pwd.getPassword() });}/** * 设置密码信息 *  * @param tb_pwd */public void update(Tb_pwd tb_pwd) {db = helper.getWritableDatabase();// 初始化SQLiteDatabase对象// 执行修改密码操作db.execSQL("update tb_pwd set password = ?",new Object[] { tb_pwd.getPassword() });}/** * 查找密码信息 *  * @return */public Tb_pwd find() {db = helper.getWritableDatabase();// 初始化SQLiteDatabase对象// 查找密码并存储到Cursor类中//public Cursor rawQuery(String sql,//                String[] selectionArgs)Runs the provided SQL and returns a Cursor over the result set. Cursor cursor = db.rawQuery("select password from tb_pwd", null);if (cursor.moveToNext())// 遍历查找到的密码信息{// 将密码存储到Tb_pwd类中//String getString(int columnIndex)Returns the value of the requested column as a String. //int getColumnIndex(String columnName)Returns the zero-based index for the given column name, or -1 if the column doesn't exist.return new Tb_pwd(cursor.getString(cursor.getColumnIndex("password")));}return null;// 如果没有信息，则返回null}public long getCount() {db = helper.getWritableDatabase();// 初始化SQLiteDatabase对象Cursor cursor = db.rawQuery("select count(password) from tb_pwd", null);// 获取密码信息的记录数if (cursor.moveToNext())// 判断Cursor中是否有数据{//long getLong(int columnIndex)Returns the value of the requested column as a long. return cursor.getLong(0);// 返回总记录数}return 0;// 如果没有数据，则返回0}// // getCount()}///PwdDAO

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