Android中对数据库进行CRUD操作手写SQL语句方式

一、首先新建Adnroid项目 然后就是新建 数据库文件

创建DBSQLiteOpenHelper类 并让它继承 SQLiteOpenHelper

public class DBSQLiteOpenHelper extends SQLiteOpenHelper {

	// 数据库的名称
	private static final String name = "CSDN";

	// 数据库的版本
	private static final int version = 2;

	public DBSQLiteOpenHelper(Context context) {
		super(context, name, null, version);

		Log.v("DBSQLiteOpenHelper", "构造器.....");
	}

	// 当数据 库第一次创建的时候 执行的方法
	@Override
	public void onCreate(SQLiteDatabase db) {
		// execSQL来挨靠 sql语句
		db.execSQL("create table person(personid integer primary key autoincrement,name varchar(20),age integer)");

		Log.v("DBSQLiteOpenHelper", "onCreate...创建执行第一次。");
	}

	// 当版本发生变化则执行此方法
	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

		db.execSQL("alter table person add account integer");

		Log.v("DBSQLiteOpenHelper", "每次更新时都执行.....");
	}

}

-----------------------------------------------------------------------------------------------------

------接下来就是对数据库进行操作了----------------------------------------------------------------------

新建 domain包 中Person 类 其中字段如下：

public class Person {



private Integer id;

private String name;

private Integer age;

private Integer account;



生成 空构造器，带参数的构造器，和set/get 方法

为了方便测试 生成String



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接下来就是实现PersonDao接口和PersonDaoImpl类了。

public interface PersonDao {
	
	/**
	 * 插入数据操作
	 * @param db
	 * @param entity
	 */
	public void insert(SQLiteDatabase db,Person entity);
	
	/**
	 * 更新操作
	 * @param db
	 * @param entity
	 */
	public void update(SQLiteDatabase db,Person entity);
	
	/**
	 * 删除操作
	 * @param db
	 * @param id
	 */
	public void delete(SQLiteDatabase db,Integer id);
	
	//查找所有
	public List<Person> findAll(SQLiteDatabase db);
	
	//获取当前页信息
	public List<Person> getNowPageInfo(SQLiteDatabase db,int nowpage,int pagesize);

	//根据ID查询
	public Person findById(SQLiteDatabase db,Integer id);
}

public class PersonDaoImpl implements PersonDao {

	@Override
	public void insert(SQLiteDatabase db, Person entity) {
		if (db.isOpen()) {
			db.execSQL(
					"insert into person(name,age,account) values(?,?,?)",
					new Object[] { entity.getName(), entity.getAge(),
							entity.getAccount() });
			db.close();
		}

	}

	@Override
	public void update(SQLiteDatabase db, Person entity) {
		if (db.isOpen()) {
			db.execSQL(
					"update person set name=?,age=?,account=? where personid=?",
					new Object[] { entity.getName(), entity.getAge(),
							entity.getAccount(), entity.getId() });
			db.close();
		}

	}

	@Override
	public void delete(SQLiteDatabase db, Integer id) {
		if (db.isOpen()) {
			db.execSQL("delete from person where personid=?",
					new Object[] { id });
			db.close();

		}
	}

	public List<Person> findAll(SQLiteDatabase db) {
		List<Person> persons = new ArrayList<Person>();
		if (db.isOpen()) {
			Cursor cursor = db.rawQuery(
					"select personid,name,age,account from person", null);

			// 判断 是否含有下一个
			while (cursor.moveToNext()) {
				// 创建 person对象
				Person person = new Person();

				// 为对象 的属性赋值
				person.setId(cursor.getInt(0));
				person.setName(cursor.getString(1));
				person.setAge(cursor.getInt(2));
				person.setAccount(cursor.getInt(3));

				// 添加到集合中
				persons.add(person);
			}

		}

		return persons;

	}

	@Override
	public List<Person> getNowPageInfo(SQLiteDatabase db, int nowpage,
			int pagesize) {

		// 开始记录
		int start = (nowpage - 1) * pagesize;

		List<Person> persons = new ArrayList<Person>();
		if (db.isOpen()) {
			Cursor cursor = db.rawQuery(
					"select personid,name,age,account from person limit ?,?",
					new String[] { start + "", pagesize + "" });

			// 判断 是否含有下一个
			while (cursor.moveToNext()) {
				// 创建 person对象
				Person person = new Person();

				// 为对象 的属性赋值
				person.setId(cursor.getInt(0));
				person.setName(cursor.getString(1));
				person.setAge(cursor.getInt(2));
				person.setAccount(cursor.getInt(3));

				// 添加到集合中
				persons.add(person);
			}

		}

		return persons;
	}

	@Override
	public Person findById(SQLiteDatabase db, Integer id) {
		Person person =null;
		if (db.isOpen()) {
			// 查询
			Cursor cursor = db.rawQuery("select personid,name,age,account from person where personid = ?", new String[]{""+id});
			// 判断是否含有下一个
			if (cursor.moveToNext()) {
				person = new Person();
				// 创建person对象
				// 为对象的属性赋值
				person.setId(cursor.getInt(0));
				person.setName(cursor.getString(1));
				person.setAge(cursor.getInt(2));
				person.setAccount(cursor.getInt(3));

			}
		}

		return person;
	}

}

------------------------功能写好后，接下来就是对此方法 进行测试 了-----------------------------------------------------



第一步：首先在AndroidManifest.xml中加入下面红色代码:
<instrumentation

android:name="android.test.InstrumentationTestRunner"

android:targetPackage="com.example.lession05_db" >

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

第二步：就是写测试方法DBTest 继承AndroidTestCase

public class DBTest extends AndroidTestCase {

	PersonDao personDao = new PersonDaoImpl();

	public void createDB() {
		DBSQLiteOpenHelper db = new DBSQLiteOpenHelper(this.getContext());
		SQLiteDatabase sdb = db.getWritableDatabase();
	}

	public void insert() {
		DBSQLiteOpenHelper db = new DBSQLiteOpenHelper(this.getContext());
		
		for(int i=1;i<=10;i++){
		SQLiteDatabase sdb = db.getWritableDatabase();
		Person entity = new Person(null, "chrp"+i, 23+i, 1000+i);
		personDao.insert(sdb, entity);
		}
	}

	
	public void update() {
		DBSQLiteOpenHelper db = new DBSQLiteOpenHelper(this.getContext());

		SQLiteDatabase sdb = db.getWritableDatabase();
		Person entity = new Person(2, "chrp99", 33, 11000);
		personDao.update(sdb, entity);
	}
	
	public void delete() {
		DBSQLiteOpenHelper db = new DBSQLiteOpenHelper(this.getContext());

		SQLiteDatabase sdb = db.getWritableDatabase();
		
		personDao.delete(sdb,11 );
	}
	
	public void getNowPageInfo(){
		DBSQLiteOpenHelper db = new DBSQLiteOpenHelper(this.getContext());

		SQLiteDatabase sdb = db.getWritableDatabase();
		
		List<Person> persons = personDao.getNowPageInfo(sdb, 1, 5);
		
		for(Person p:persons){
			System.out.println(p.toString());
		}
	}
	
	public void findAll(){
		//创建数据库的管理的对象
		DBSQLiteOpenHelper db = new DBSQLiteOpenHelper(this.getContext());
		//获取 SqLiteDatebase实例对象 才能创建数据库
		SQLiteDatabase sdb = db.getWritableDatabase();
		
		List<Person> persons = personDao.findAll(sdb);
		
		for(Person p:persons){
			System.out.println(p.toString());
		}
	}
	
	public void findById(){
		//创建数据库的管理的对象
		DBSQLiteOpenHelper db = new DBSQLiteOpenHelper(this.getContext());
		//获取 SqLiteDatebase实例对象 才能创建数据库
		SQLiteDatabase sdb = db.getWritableDatabase();
		
		Person p = personDao.findById(sdb, 3);
		
		if(p!=null){
			System.out.println(p.toString());
		}
	}
	

}