Sqlite所作增删改查示例

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);
    }
}