网站的差异,网络营销工程师前景,兰州企业建设网站,外贸搜素网站1、sqlliet简单介绍及相关技术要点 A、可以保存任何类型的数据不限长度 但整形主键的话必须为整数 只能编写标准sql语句 分页和mysql一样 imit 5 offset 3 limit 3,5 跳过前面3条 B、写一个类继承SQLiteOpenHelper 数据库文件所在路径为#xff1a;应用… 1、sqlliet简单介绍及相关技术要点 A、可以保存任何类型的数据不限长度 但整形主键的话必须为整数 只能编写标准sql语句 分页和mysql一样 imit 5 offset 3 limit 3,5 跳过前面3条 B、写一个类继承SQLiteOpenHelper 数据库文件所在路径为应用的包下面的databases 最好是少建类 可以少占内存 SQLiteDatabase database openHelp.getWritableDatabase();//对数据要更改,该方法以读和写的方式打开数据库 SQLiteDatabase database2openHelp.getReadableDatabase();//先用可以写的方式打开数据库如果打开失败再以只读的方式打开数据库 C、SqliteDev工具下载地址http://download.csdn.net/source/3302231 Person package com.tjp.model; public class Person { private int personId; private String name; public Person() { super (); } public Person( int personId, String name) { super (); this .personId personId; this .name name; } public int getPersonId() { return personId; } public void setPersonId( int personId) { this .personId personId; } public String getName() { return name; } public void setName(String name) { this .name name; } Override public String toString() { // TODO Auto-generated method stub return name name personId personId; }} DBOpenHelp package com.tjp.service; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import android.database.sqlite.SQLiteDatabase.CursorFactory; public class DBOpenHelp extends SQLiteOpenHelper { private static final String DBNAME tjp.db ; // 数据库名称 private static final int DBVERSION 1 ; // 数据版本 public DBOpenHelp(Context context, String name, CursorFactory factory, int version) { super (context, name, factory, version); // context 上下文 name 数据库名称以db为后缀名 factory 游标工厂 version数据库版本号 // TODO Auto-generated constructor stub } public DBOpenHelp(Context context) { super (context, DBNAME, null , DBVERSION); } /** * 数据库第一次创建的时候被调用 */ Override public void onCreate(SQLiteDatabase db) { String sql create table person(personid integer primary key autoincrement,name varchar(20)) ; db.execSQL(sql); // 执行有更新行为的sql语句 } /** * 在软件升级的时候当数据库的版本发送改变的时候 */ Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // TODO Auto-generated method stub }} PersonService package com.tjp.service; import java.util.ArrayList; import java.util.List; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import com.tjp.model.Person; public class PersonService { private DBOpenHelp openHelp null ; private Context context; public PersonService(Context context) { this .context context; openHelp new DBOpenHelp(context); } public void save(Person person){ SQLiteDatabase database openHelp.getWritableDatabase(); // 对数据要更改,该方法以读和写的方式打开数据库,有缓存功能 database.execSQL( insert into person(name) values(?) , new Object[]{person.getName()}); } public void update(Person person){ SQLiteDatabase database openHelp.getWritableDatabase(); database.execSQL( update person set name? where personid? , new Object[]{person.getName(),person.getPersonId()}); } public void delete( int personId){ SQLiteDatabase database openHelp.getWritableDatabase(); database.execSQL( delete from person where personid? , new Object[]{personId}); } public Person find( int personId){ SQLiteDatabase database openHelp.getWritableDatabase(); Person person null ; Cursor cursor database.rawQuery( select * from person where personid? , new String[]{String.valueOf(personId).toString()}); if (cursor.moveToFirst()){ // 如果移动成功了表示存在 int personIda cursor.getInt(cursor.getColumnIndex( personid )); String name cursor.getString(cursor.getColumnIndex( name )); person new Person(personIda,name); } cursor.close(); return person; } public List Person getScrollDate( int offerset, int maxResult){ List Person persons new ArrayList Person (); SQLiteDatabase database openHelp.getWritableDatabase(); String sql select * from person limit ?,? ; Cursor cursor database.rawQuery(sql, new String[]{String.valueOf(offerset),String.valueOf(maxResult)}); while (cursor.moveToNext()){ int personIda cursor.getInt(cursor.getColumnIndex( personid )); String name cursor.getString(cursor.getColumnIndex( name )); Person person new Person(personIda,name); persons.add(person); } return persons; } public long getCount(){ SQLiteDatabase database openHelp.getWritableDatabase(); Cursor cursor database.rawQuery( select count(*) from person , null ); cursor.moveToFirst(); int count cursor.getInt( 0 ); cursor.close(); return count; }} PersonServiceTest package com.tjp.db; import java.util.List; import com.tjp.model.Person; import com.tjp.service.DBOpenHelp; import com.tjp.service.PersonService; import android.test.AndroidTestCase; import android.util.Log; public class PersonServiceTest extends AndroidTestCase { private static final String TAG PersonServiceTest ; public void testCreateDb() throws Exception{ DBOpenHelp help new DBOpenHelp( this .getContext()); help.getWritableDatabase(); // 第一次调用该方法创建数据库 } public void testsave() throws Exception{ PersonService personService new PersonService( this .getContext()); Person person new Person( 1 , 谭建平 ); personService.save(person); Person person1 new Person( 1 , 谭建平1 ); personService.save(person1); Person person2 new Person( 1 , 谭建平2 ); personService.save(person2); Person person3 new Person( 1 , 谭建平3 ); personService.save(person3); Person person4 new Person( 1 , 谭建平4 ); personService.save(person4); Person person5 new Person( 1 , 谭建平5 ); personService.save(person5); Person person6 new Person( 1 , 谭建平6 ); personService.save(person6); } public void testupdate() throws Exception{ PersonService personService new PersonService( this .getContext()); Person person new Person( 1 , 老李 ); personService.update(person); } public void testdelete() throws Exception{ PersonService personService new PersonService( this .getContext()); personService.delete( 1 ); } public void tesfind() throws Exception{ PersonService personService new PersonService( this .getContext()); Person person personService.find( 1 ); Log.i(TAG, person.getName()); } public void testscorll() throws Exception{ PersonService personService new PersonService( this .getContext()); List Person persons personService.getScrollDate( 0 , 2 ); for (Person person : persons){ Log.i(TAG, person.toString()); } } public void testcount() throws Exception{ PersonService personService new PersonService( this .getContext()); Log.i(TAG, personService.getCount() ); }} 转载于:https://www.cnblogs.com/tjpfly/archive/2011/05/23/sqlite_c_r_u_d_SqliteDev.html
