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：

Plain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

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

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