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;
    }

}