Android 如何对sqlite数据库进行增删改[insert、update和delete] 操作

               在android开发中，我们常常用sqlite来存储用户信息，如何进行sqlite常规操作呢，请参阅下面的示例代码：

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); } }
主要用到的类：SQLiteOpenHelper、SQLiteDatabase及ContentValues