Android SQLite数据库增删改查操作的案例分析

Person实体类


代码如下:

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


代码如下:

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


代码如下:

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


代码如下:

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