使用api方式查询数据库和sqlite3工具

用API方式查询数据库：

DAO：

package com.itheima28.sqlitedemo.dao;
import java.util.ArrayList;
import java.util.List;
import com.itheima28.sqlitedemo.db.PersonSQLiteOpenHelper;
import com.itheima28.sqlitedemo.entities.Person;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
public class PersonDao2 {
	
	private static final String TAG = "TestCase";

	private PersonSQLiteOpenHelper mOpenHelper; // 数据库的帮助对象
	public PersonDao2(Context context) {
		mOpenHelper = new PersonSQLiteOpenHelper(context);
	}
	/*
	 * 添加到person表一条数据
	 */
	public void insert(Person person) {
		SQLiteDatabase db = mOpenHelper.getWritableDatabase();
		if (db.isOpen()) { // 判断数据库是否打开
			 ContentValues values=new ContentValues();
			 values.put("name",person.getName());
			 values.put("age",person.getAge());
		     long id=db.insert("person", null, values);
			 Log.i(TAG,"id:  "+id); 
			db.close(); // 数据库关闭
		}

	}

	public void delete(int id) {
		// 获得可写的数据库对象
		SQLiteDatabase db = mOpenHelper.getWritableDatabase();
		if (db.isOpen()) {
			String whereClause="_id=?";
			String[] whereArgs={id+" "};
			int count=db.delete("person", whereClause, whereArgs);
			Log.i(TAG,"删除了:   "+count+"行");
			db.close(); // 数据库关闭
		}
	}

	public void update(int id, String name) {
		SQLiteDatabase db = mOpenHelper.getWritableDatabase();
		if (db.isOpen()) {
			if (db.isOpen()) {
			   ContentValues values=new ContentValues();
               values.put("name", name);
               values.put("name", name);
               int count=db.update("person", values, "_id=?", new String[]{id+" "});
               Log.i(TAG,"修改了:   "+count);
				db.close(); // 数据库关闭
			}
		}
	}

	public List<Person> queryAll() {
		SQLiteDatabase db = mOpenHelper.getWritableDatabase();
		if (db.isOpen()) {
			String[] columns={"_id","name","age"};
			String selection=null;
			String[] selectionArgs=null;
			String groupBy=null;
			String having=null;
			String orderBy=null;
			Cursor cursor=db.query("person", columns, selection, selectionArgs, groupBy, having, orderBy);
			List<Person> personList = new ArrayList();
			if (cursor != null && cursor.getCount() >= 0) {
				int id;
				int age;
				String name;
				while (cursor.moveToNext()) {
					id = cursor.getInt(0); // 取第零列的数据
					name = cursor.getString(1);
					age = cursor.getInt(2);
					personList.add(new Person(id, name, age));
				}
				db.close();
				return personList;
			}
			db.close();
		}
		return null;
	}

	public Person queryItem(int id) {
		SQLiteDatabase db = mOpenHelper.getWritableDatabase();
		if (db.isOpen()) {
			String[] columns={"_id","name","age"};
			String selection="_id=?";
			String[] selectionArgs={id+" "};
			String groupBy=null;
			String having=null;
			String orderBy=null;
			Cursor cursor=db.query("person", columns, selection, selectionArgs, groupBy, having, orderBy);
			if (cursor != null && cursor.moveToFirst()) {//如果cursor不为空,且可以移动到第一行
				int _id = cursor.getInt(0);
				String name = cursor.getString(1);
				int age = cursor.getInt(2);
				db.close();
				return new Person(_id, name, age);
			}
			db.close();
		}
		return null;
	}

}

测试：

package com.itheima28.sqlitedemo.test;

import java.util.List;

import com.itheima28.sqlitedemo.dao.PersonDao2;
import com.itheima28.sqlitedemo.db.PersonSQLiteOpenHelper;
import com.itheima28.sqlitedemo.entities.Person;

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

public class TestCase2 extends AndroidTestCase {

	private static final String TAG = "TestCase";

	public void test(){
		//数据库什么时候创建
		PersonSQLiteOpenHelper openHelper=new PersonSQLiteOpenHelper(getContext());
		
		//第一次连接数据库是创建数据库文件,会执行onCreate方法
		openHelper.getReadableDatabase();
		
	}
	
	public void testInsert(){
		PersonDao2 dao=new PersonDao2(getContext());
	    dao.insert(new Person(99,"q",20));
	   
	
	}
	
	public void testDelete(){
		PersonDao2 dao=new PersonDao2(getContext());
        dao.delete(1);
	}
	
	public void testUpdate(){
		PersonDao2 dao=new PersonDao2(getContext());
        dao.update(1, "凤姐");
	}
	
	
	public void testQueryAll(){
		PersonDao2 dao=new PersonDao2(getContext());
        List<Person> personList=dao.queryAll();
        for(Person person:personList){
        	Log.i(TAG,person.toString());
        }
		
	}
	
	public void testQueryItem(){
		PersonDao2 dao=new PersonDao2(getContext());
        Person person=dao.queryItem(2);
        Log.i(TAG,person.toString());
	}
}

sqlite3的使用：

可以利用Android自带工具，在dos下通过shell命令操作数据库

进入数据库所在目录：

sqlite + 数据库全名进入sqlite>命令模式

.mode column更改排列样式

接下来就可以通过sql语句使用查询该数据库了。