十一、SQLite数据库增删改查操作案例

Person实体类

package com.ljq.domain;


public class Person {
private Integer id;
private String name;
private String phone;

public Person() {
super();
}

public Person(String name, String phone) {
super();
this.name = name;
this.phone = phone;
}

public Person(Integer id, String name, String phone) {
super();
this.id = id;
this.name = name;
this.phone = phone;
}

public Integer getId() {
return id;
}

public void setId(Integer id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getPhone() {
return phone;
}

public void setPhone(String phone) {
this.phone = phone;
}

}

         

           

DBOpenHelper数据库关联类

package com.ljq.db;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DBOpenHelper extends SQLiteOpenHelper {
// 类没有实例化,是不能用作父类构造器的参数,必须声明为静态
private static final String DBNAME = "ljq.db";
private static final int VERSION = 1;

// 第三个参数CursorFactory指定在执行查询时获得一个游标实例的工厂类,
// 设置为null,代表使用系统默认的工厂类
public DBOpenHelper(Context context) {
super(context, DBNAME, null, VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(
"CREATE TABLE PERSON (ID INTEGER PRIMARY KEY AUTOINCREMENT, NAME VARCHAR(20), PHONE VARCHAR(20))");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// 注:生产环境上不能做删除操作
db.execSQL("DROP TABLE IF EXISTS PERSON");
onCreate(db);
}
}

            

               

PersonService业务类

package com.ljq.db;

import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.database.Cursor;

import com.ljq.domain.Person;

public class PersonService {
private DBOpenHelper dbOpenHelper = null;

/**
* 构造函数
*
* 调用getWritableDatabase()或getReadableDatabase()方法后,会缓存SQLiteDatabase实例;
* 因为这里是手机应用程序,一般只有一个用户访问数据库,所以建议不关闭数据库,保持连接状态。
* getWritableDatabase(),getReadableDatabase的区别是当数据库写满时,调用前者会报错,调用后者不会,
* 所以如果不是更新数据库的话,最好调用后者来获得数据库连接。
*
* 对于熟悉SQL语句的程序员最好使用exeSQL(),rawQuery(),因为比较直观明了
*
*
@param context
*/
public PersonService(Context context){
dbOpenHelper
= new DBOpenHelper(context);
}

public void save(Person person){
dbOpenHelper.getWritableDatabase().execSQL(
"insert into person(name, phone) values (?, ?)",
new Object[]{person.getName(), person.getPhone()});
}

public void update(Person person){
dbOpenHelper.getWritableDatabase().execSQL(
"update person set name=?, phone=? where id=?",
new Object[]{person.getName(), person.getPhone(), person.getId()});
}

public void delete(Integer... ids){
if(ids.length>0){
StringBuffer sb
= new StringBuffer();
for(Integer id : ids){
sb.append(
"?").append(",");
}
sb.deleteCharAt(sb.length()
- 1);
dbOpenHelper.getWritableDatabase().execSQL(
"delete from person where id in ("+sb+")", (Object[])ids);
}
}

public Person find(Integer id){
Cursor cursor
= dbOpenHelper.getReadableDatabase().rawQuery("select id, name, phone from person where id=?",
new String[]{String.valueOf(id)});
if(cursor.moveToNext()){
int personid = cursor.getInt(0);
String name
= cursor.getString(1);
String phone
= cursor.getString(2);
return new Person(personid, name, phone);
}
return null;
}

public long getCount(){
Cursor cursor
= dbOpenHelper.getReadableDatabase().query("person",
new String[]{"count(*)"}, null,null,null,null,null);
if(cursor.moveToNext()){
return cursor.getLong(0);
}
return 0;
}

/**
* 分页
*
*
@param startResult 偏移量,默认从0开始
*
@param maxResult 每页显示的条数
*
@return
*/
public List<Person> getScrollData(int startResult, int maxResult){
List
<Person> persons = new ArrayList<Person>();
//Cursor cursor = dbOpenHelper.getReadableDatabase().query("person", new String[]{"id, name, phone"},
// "name like ?", new String[]{"%ljq%"}, null, null, "id desc", "1,2");
Cursor cursor = dbOpenHelper.getReadableDatabase().rawQuery("select * from person limit ?,?",
new String[]{String.valueOf(startResult), String.valueOf(maxResult)});
while(cursor.moveToNext()) {
int personid = cursor.getInt(0);
String name
= cursor.getString(1);
String phone
= cursor.getString(2);
persons.add(
new Person(personid, name, phone));
}
return persons;
}



}

             

                  

PersonServiceTest测试类

package com.ljq.test;

import java.util.List;

import com.ljq.db.PersonService;
import com.ljq.domain.Person;

import android.test.AndroidTestCase;
import android.util.Log;

public class PersonServiceTest extends AndroidTestCase{
private final String TAG = "PersonServiceTest";

public void testSave() throws Exception{
PersonService personService
= new PersonService(this.getContext());
personService.save(
new Person("zhangsan1", "059188893343"));
personService.save(
new Person("zhangsan2", "059188893343"));
personService.save(
new Person("zhangsan3", "059188893343"));
personService.save(
new Person("zhangsan4", "059188893343"));
personService.save(
new Person("zhangsan5", "059188893343"));
}

public void testUpdate() throws Exception{
PersonService personService
= new PersonService(this.getContext());
Person person
= personService.find(1);
person.setName(
"linjiqin");
personService.update(person);
}

public void testFind() throws Exception{
PersonService personService
= new PersonService(this.getContext());
Person person
= personService.find(1);
Log.i(TAG, person.getName());
}

public void testList() throws Exception{
PersonService personService
= new PersonService(this.getContext());
List
<Person> persons = personService.getScrollData(0, 10);
for(Person person : persons){
Log.i(TAG, person.getId()
+ " : " + person.getName());
}
}

public void testCount() throws Exception{
PersonService personService
= new PersonService(this.getContext());
Log.i(TAG, String.valueOf(personService.getCount()));
}

public void testDelete() throws Exception{
PersonService personService
= new PersonService(this.getContext());
personService.delete(
1);
}

public void testDeleteMore() throws Exception{
PersonService personService
= new PersonService(this.getContext());
personService.delete(
new Integer[]{2, 5, 6});
}
}

                 

            

运行结果

posted on 2011-05-27 15:09  Ruthless  阅读(10145)  评论(4编辑  收藏  举报