Android下利用SQLite数据库实现增删改查

1： 首先介绍如何利用adb查看数据库

 

1： adb shell

2： cd /data/data/包名/databases

3:  sqlite3 数据库

4   接下来就可以进行数据库的sql语法的使用了

 

bean对象：

public class Person {

    

    private int id;

    private String name;

    private String number;

    

}

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数据库的创建以及表的创建：

package com.example.db;



import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteDatabase.CursorFactory;

import android.database.sqlite.SQLiteOpenHelper;



public class BaseDao extends SQLiteOpenHelper{



    /**

     * 数据库的构造方法， 用来定义数据库的名称， 数据库查询结果集， 数据库的版本号

     * 

     */

    public BaseDao(Context context) {

        super(context, "person.db", null, 1);

    }

    

    /**

     *数据库别创建的时候调用的方法

     * 

     */

    @Override

    public void onCreate(SQLiteDatabase db) {

        //初始化数据库的表结构

        db.execSQL("create table person (id integer primary key autoincrement, name varchar(20), number varchar(20))");

    }



    @Override

    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        // TODO Auto-generated method stub

        

    }



}

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利用纯SQL语句实现增删改查

 

package com.example.dao;



import java.util.ArrayList;

import java.util.List;



import android.content.Context;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;



import com.example.bean.Person;

import com.example.db.BaseDao;



public class PersonDaoSQL {

    

    private BaseDao helper; //helper

    

    /**

     * 在构造方法中实例化helper

     * @param context

     */

    public PersonDaoSQL(Context  context) {

        helper = new BaseDao(context);

    }

    

    /**

     * 增

     * @param person

     */

    public void add(Person person) {

        SQLiteDatabase db = helper.getWritableDatabase();

        db.execSQL("insert into person (name, number) values(?, ?)", new String[] {person.getName(), person.getNumber()});

        db.close();

    }

    

    /**

     * 按姓名查

     * @param person

     * @return

     */

    public boolean find(Person person) {

        SQLiteDatabase db = helper.getReadableDatabase();

        Cursor cursor = db.rawQuery("select * from person where name = ?", new String[] {person.getName()});

        boolean result = cursor.moveToNext();

        cursor.close();

        db.close();

        return result;

    }

    

    /**

     * 删除一条记录

     */

    public void delete(Person person) {

        SQLiteDatabase db = helper.getWritableDatabase();

        db.execSQL("delete from person where name = ?", new String[]{person.getName()});

        db.close();

    }

    

    /**

     * 更新

     */

    public void update(Person person) {

        SQLiteDatabase db = helper.getWritableDatabase();

        db.execSQL("update person set number = ? where name = ?", new String[]{person.getNumber(),person.getName()});

        db.close();

    }

    public List<Person> findAll() {

        SQLiteDatabase db = helper.getReadableDatabase();

        Cursor cursor = db.rawQuery("select id, name, number from person", null);

        List<Person> persons = new ArrayList<Person>();

        Person person = null;

        while (cursor.moveToNext()) {

            int id = cursor.getInt(cursor.getColumnIndex("id"));

            String name = cursor.getString(cursor.getColumnIndex("name"));

            String number = cursor.getString(cursor.getColumnIndex("number"));

            person = new Person(id, name, number);

            persons.add(person);

        }

        cursor.close();

        db.close();

        return persons;

    }



}

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利用API实现增删改查：

package com.example.dao;



import java.util.ArrayList;

import java.util.List;



import android.content.ContentValues;

import android.content.Context;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;



import com.example.bean.Person;

import com.example.db.BaseDao;



public class PersonDaoAPI {

    

    private BaseDao helper; //helper

    /**

     * 在构造方法中实例化helper

     * @param context

     */

    public PersonDaoAPI(Context  context) {

        helper = new BaseDao(context);

    }

    

    public long add(Person person) {

        SQLiteDatabase db = helper.getWritableDatabase();

        

        ContentValues values = new ContentValues();

        values.put("name", person.getName());

        values.put("number", person.getNumber());

        long result = db.insert("person", null, values);

        

        db.close();

        return result;

    }

    

    public int delete(Person person) {

        SQLiteDatabase db = helper.getWritableDatabase();

        

        int result = db.delete("person", "name = ?", new String[] {person.getName()});        

        db.close();

        

        return result;

    }

    

    public int update(Person person) {

        SQLiteDatabase db = helper.getWritableDatabase();

        

        ContentValues values = new ContentValues();

        values.put("number", person.getNumber());

        

        int result = db.update("person", values, "name=?", new String[] {person.getName()});    

        db.close();

        

        return result;

    }

    

    public boolean find(Person person) {

        SQLiteDatabase db = helper.getWritableDatabase();

        

        Cursor cursor = db.query("person", null, "name = ?", new String[]{person.getName()}, null, null, null);

        boolean result = cursor.moveToNext();

        

        db.close();

        return result;

    }

    

    public List<Person> findAll() {

        SQLiteDatabase db = helper.getWritableDatabase();

        

        Cursor cursor = db.query("person", null, null, null, null, null,null);

        List<Person> persons = new ArrayList<Person>();

        Person person = null;

        while (cursor.moveToNext()) {

            int id = cursor.getInt(cursor.getColumnIndex("id"));

            String name = cursor.getString(cursor.getColumnIndex("name"));

            String number = cursor.getString(cursor.getColumnIndex("number"));

            person = new Person(id, name, number);

            persons.add(person);

        }

        

        db.close();

        return persons;

    }

    



}

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利用Junit进行测试， 

注意一定要在AndroidManifest.xml中添加： 

<instrumentation
android:name="android.test.InstrumentationTestRunner"
android:targetPackage="com.example.db" />

 

和

 

 <uses-library android:name="android.test.runner" />

 

package com.example.test;



import java.util.List;



import android.test.AndroidTestCase;



import com.example.bean.Person;

import com.example.dao.PersonDaoAPI;

import com.example.dao.PersonDaoSQL;

import com.example.db.BaseDao;



public class TestPersonDB extends AndroidTestCase {

    /**

     * 测试数据库的创建

     * @throws Exception

     */

    public void testCreateDB() throws Exception{

        BaseDao helper = new BaseDao(getContext());

        helper.getReadableDatabase();

    }

    

    /**

     * 测试添加

     */

    public void testAdd() {

        //PersonDaoSQL dao = new PersonDaoSQL(getContext());

        PersonDaoAPI dao = new PersonDaoAPI(getContext());

        for (int i = 0; i < 10 ; ++i) {

            Person person = new Person("lisi" + i + 1, "1347515770" + i);

            dao.add(person);

        }

    }

    /**

     * 测试修改

     */

    public void testUpdate() {

        //PersonDaoSQL dao = new PersonDaoSQL(getContext());

        PersonDaoAPI dao = new PersonDaoAPI(getContext());

        Person person = new Person("lisi" + 11, "1347515770" + "x");

        dao.update(person);

    }

    

    /**

     * 测试单个查询查询

     */

    public void testFind() {

        //PersonDaoSQL dao = new PersonDaoSQL(getContext());

        PersonDaoAPI dao = new PersonDaoAPI(getContext());

        Person person = new Person("lisi" + 21, "1347515770" + "x");

        boolean result = dao.find(person);

        assertEquals(true, result);

    }

    

    /**

     * 查询所有

     */

    public void testFindAll() {

        //PersonDaoSQL dao = new PersonDaoSQL(getContext());

        PersonDaoAPI dao = new PersonDaoAPI(getContext());

        List<Person> persons = dao.findAll();

        for (Person person : persons) {

            System.out.println(person.getName());

        }

    }

    

    /**

     * 删除

     */

    public void testDelete() {

        PersonDaoSQL dao = new PersonDaoSQL(getContext());

        Person person = new Person("lisi" + 21, "1347515770" + "x");

        dao.delete(person);

    }



}

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