Android 系统API实现数据库的增删改查和SQLite3工具的使用

在《Android SQL语句实现数据库的增删改查》中介绍了使用sql语句来实现数据库的增删改查操作，本文介绍Android 系统API实现数据库的增删改查和SQLite3工具的使用。

系统API实现数据库的增删改查

相关代码修改如下：

package com.wuyudong.db.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.wuyudong.db.PersonSQLiteOpenHelper;

import com.wuyudong.db.domain.Person;

public class PersonDao {

    private PersonSQLiteOpenHelper helper;

    public PersonDao(Context context) {

        helper = new PersonSQLiteOpenHelper(context);

    }

    /**

     * 添加一条记录到数据库

     *

     * @param name

     *            姓名

     * @param number

     *            电话

     */

    public void add(String name, String number) {

        SQLiteDatabase db = helper.getWritableDatabase();

        // db.execSQL("insert into person (name,number) values (?,?)",

        // new Object[] { name, number });

        ContentValues values = new ContentValues();

        values.put("name", name);

        values.put("number", number);

        db.insert("person", null, values);

        db.close();

    }

    /**

     * 查询记录是否存在

     *

     * @param name

     *            姓名 return true存在， false不存在

     */

    public boolean find(String name) {

        SQLiteDatabase db = helper.getReadableDatabase();

        // Cursor cursor = db.rawQuery("select * from person where name=?",

        // new String[] { name });

        Cursor cursor = db.query("person", null, "name=?",

                new String[] { name }, null, null, null);

        boolean result = cursor.moveToNext();

        cursor.close();

        db.close();

        return result;

    }

    /**

     *

     * @param name

     *            要修改的人的姓名

     * @param newnumber

     *            新的号码

     */

    public void update(String name, String newnumber) {

        SQLiteDatabase db = helper.getReadableDatabase();

        // db.execSQL("update person set number=? where name=?", new Object[] {

        // newnumber, name });

        ContentValues values = new ContentValues();

        values.put("number", newnumber);

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

        db.close();

    }

    /**

     * 删除一条记录

     *

     * @param name

     */

    public void delete(String name) {

        SQLiteDatabase db = helper.getReadableDatabase();

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

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

        db.close();

    }

    /**

     * 返回全部的数据库信息

     *

     * @return

     */

    public List<Person> findAll() {

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

        SQLiteDatabase db = helper.getReadableDatabase();

        // Cursor cursor = db.rawQuery("select * from person", null);

        Cursor cursor = db.query("person", new String[] { "name", "id",

                "number" }, null, null, null, null, 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 person = new Person(id, name, number);

            persons.add(person);

        }

        cursor.close();

        db.close();

        return persons;

    }

}