sqlite3 数据库实战并测试

实体类：
com.itheima28.sqlitedemo.entities包
public class Person {

    private int id;
    private String name;
    private int age;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public Person() {
        super();
        // TODO Auto-generated constructor stub
    }
    public Person(int id, String name, int age) {
        super();
        this.id = id;
        this.name = name;
        this.age = age;
    }
    @Override
    public String toString() {
        return "Person [id=" + id + ", name=" + name + ", age=" + age + "]";
    }
}

数据库帮助类
com.itheima28.sqlitedemo.db包：
/**
 * @author andong
 * 数据库帮助类, 用于创建和管理数据库的.
 */
public class PersonSQLiteOpenHelper extends SQLiteOpenHelper {

    private static final String TAG = "PersonSQLiteOpenHelper";

    /**
     * 数据库的构造函数 ：用来定义数据库的名称 ，数据库查询的结果，数据库的版本
     * @param context :作用：数据库在哪里进行创建 
     * 
     * name 数据库名称
     * factory 游标工程
     * version 数据库的版本号 不可以小于1
     */
    public PersonSQLiteOpenHelper(Context context) {
        super(context, "itheima28.db", null, 2);
    }

    /**
     * 数据库第一次创建时回调此方法.
     * 初始化一些表
     */
    @Override
    public void onCreate(SQLiteDatabase db) {

        // 操作数据库
        String sql = "create table person(_id integer primary key, name varchar(20), age integer);";
        db.execSQL(sql);        // 创建person表
    }

    /**
     * 数据库的版本号更新时回调此方法,
     * 更新数据库的内容(删除表, 添加表, 修改表)
     */
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        if(oldVersion == 1 && newVersion == 2) {
            Log.i(TAG, "数据库更新啦");
            // 在person表中添加一个余额列balance
            db.execSQL("alter table person add balance integer;");
        }
    }

}

DAO类
com.itheima28.sqlitedemo.dao：
public class PersonDao {

    private PersonSQLiteOpenHelper mOpenHelper; // 数据库的帮助类对象

    public PersonDao(Context context) {
        mOpenHelper = new PersonSQLiteOpenHelper(context);
    }

    /**
     * 添加到person表一条数据
     * @param person
     */
    public void insert(Person person) {
        SQLiteDatabase db = mOpenHelper.getWritableDatabase();
        if(db.isOpen()) {   // 如果数据库打开, 执行添加的操作

            // 执行添加到数据库的操作
            db.execSQL("insert into person(name, age) values(?, ?);", new Object[]{person.getName(), person.getAge()});

            db.close(); // 数据库关闭
        }
    }

    /**
     * 更据id删除记录
     * @param id
     */
    public void delete(int id) {
        SQLiteDatabase db = mOpenHelper.getWritableDatabase();  // 获得可写的数据库对象
        if(db.isOpen()) {   // 如果数据库打开, 执行添加的操作

            db.execSQL("delete from person where _id = ?;", new Integer[]{id});

            db.close(); // 数据库关闭
        }
    }


    /**
     * 根据id找到记录, 并且修改姓名
     * @param id
     * @param name
     */
    public void update(int id, String name) {
        SQLiteDatabase db = mOpenHelper.getWritableDatabase();
        if(db.isOpen()) {   // 如果数据库打开, 执行添加的操作

            db.execSQL("update person set name = ? where _id = ?;", new Object[]{name, id});

            db.close(); // 数据库关闭
        }
    }

    public List queryAll() {
        SQLiteDatabase db = mOpenHelper.getReadableDatabase();  // 获得一个只读的数据库对象
        if(db.isOpen()) {

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

            if(cursor != null && cursor.getCount() > 0) {
                List personList = new ArrayList();
                int id;
                String name;
                int age;
                while(cursor.moveToNext()) {
                    id = cursor.getInt(cursor.getColumnIndex("_id"));   // 取第0列的数据 id
                    name = cursor.getString(cursor.getColumnIndex("name")); // 取姓名
                    age = cursor.getInt(cursor.getColumnIndex("age"));      // 取年龄
                    personList.add(new Person(id, name, age));
                }
                cursor.close();
                db.close();
                return personList;
            }
            db.close();
        }
        return null;
    }

    /**
     * 根据id查询人
     * @param id
     * @return
     */
    public Person queryItem(int id) {
        SQLiteDatabase db = mOpenHelper.getReadableDatabase();  // 获得一个只读的数据库对象
        if(db.isOpen()) {
            Cursor cursor = db.rawQuery("select _id, name, age from person where _id = ?;", new String[]{String.valueOf(id)});
            if(cursor != null && cursor.moveToFirst()) {
                int _id = cursor.getInt(cursor.getColumnIndex("_id"));
                String name = cursor.getString(cursor.getColumnIndex("name"));
                int age = cursor.getInt(cursor.getColumnIndex("age"));
                cursor.close();
                db.close();
                return new Person(_id, name, age);
            }
            db.close();
        }
        return null;
    }
}

public class PersonDao2 {

    private static final String TAG = "PersonDao2";
    private PersonSQLiteOpenHelper mOpenHelper; // 数据库的帮助类对象

    public PersonDao2(Context context) {
        mOpenHelper = new PersonSQLiteOpenHelper(context);
    }

    /**
     * 添加到person表一条数据
     * @param person
     */
    public void insert(Person person) {
        SQLiteDatabase db = mOpenHelper.getWritableDatabase();
        if(db.isOpen()) {   // 如果数据库打开, 执行添加的操作

            ContentValues values = new ContentValues();
            values.put("name", person.getName());       // key作为要存储的列名, value对象列的值
            values.put("age", person.getAge());
            long id = db.insert("person", "name", values);
            Log.i(TAG, "id: " + id);

            db.close(); // 数据库关闭
        }
    }

    /**
     * 更据id删除记录
     * @param id
     */
    public void delete(int id) {
        SQLiteDatabase db = mOpenHelper.getWritableDatabase();  // 获得可写的数据库对象
        if(db.isOpen()) {   // 如果数据库打开, 执行添加的操作

            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
        }
    }


    /**
     * 根据id找到记录, 并且修改姓名
     * @param id
     * @param name
     */
    public void update(int id, String name) {
        SQLiteDatabase db = mOpenHelper.getWritableDatabase();
        if(db.isOpen()) {   // 如果数据库打开, 执行添加的操作
            ContentValues values = new ContentValues();
            values.put("name", name);

            int count  = db.update("person", values, "_id = ?", new String[]{id + ""});

            Log.i(TAG, "修改了: " + count + "行");

            db.close(); // 数据库关闭
        }
    }

    public List queryAll() {
        SQLiteDatabase db = mOpenHelper.getReadableDatabase();  // 获得一个只读的数据库对象
        if(db.isOpen()) {
            String[] columns = {"_id", "name", "age"};  // 需要的列
            String selection = null;    // 选择条件, 给null查询所有
            String[] selectionArgs = null;  // 选择条件的参数, 会把选择条件中的? 替换成数据中的值
            String groupBy = null;  // 分组语句  group by name
            String having = null;   // 过滤语句
            String orderBy = null;  // 排序

            Cursor cursor = db.query("person", columns, selection, selectionArgs, groupBy, having, orderBy);

            int id;
            String name;
            int age;
            if(cursor != null && cursor.getCount() > 0) {
                List personList = new ArrayList();

                while(cursor.moveToNext()) {    // 向下移一位, 知道最后一位, 不可以往下移动了, 停止.
                    id = cursor.getInt(0);
                    name = cursor.getString(1);
                    age = cursor.getInt(2);

                    personList.add(new Person(id, name, age));
                }

                db.close();
                return personList;
            }
            db.close();
        }
        return null;
    }

    /**
     * 根据id查询人
     * @param id
     * @return
     */
    public Person queryItem(int id) {
        SQLiteDatabase db = mOpenHelper.getReadableDatabase();  // 获得一个只读的数据库对象
        if(db.isOpen()) {
            String[] columns = {"_id", "name", "age"};  // 需要的列
            String selection = "_id = ?";   // 选择条件, 给null查询所有
            String[] selectionArgs = {id + ""}; // 选择条件的参数, 会把选择条件中的? 替换成数据中的值
            String groupBy = null;  // 分组语句  group by name
            String having = null;   // 过滤语句
            String orderBy = null;  // 排序

            Cursor cursor = db.query("person", columns, selection, selectionArgs, groupBy, having, orderBy);

            if(cursor != null && cursor.moveToFirst()) {        // cursor对象不为null, 并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;
    }
}

测试类
com.itheima28.sqlitedemo.test

public class TestCase 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());

        // 第一次连接数据库时创建数据库文件. onCreate会被调用
        openHelper.getReadableDatabase();
    }

    public void testInsert() {
        PersonDao dao = new PersonDao(getContext());

        dao.insert(new Person(1, "冠希", 28));
    }

    public void testDelete() {
        PersonDao dao = new PersonDao(getContext());
        dao.delete(1);
    }

    public void testUpdate() {
        PersonDao dao = new PersonDao(getContext());
        dao.update(3, "凤姐");
    }

    public void testQueryAll() {
        PersonDao dao = new PersonDao(getContext());
        List personList = dao.queryAll();

        for (Person person : personList) {
            Log.i(TAG, person.toString());
        }
    }

    public void testQueryItem() {
        PersonDao dao = new PersonDao(getContext());
        Person person = dao.queryItem(4);
        Log.i(TAG, person.toString());
    }

    public void testTransaction() {
        PersonSQLiteOpenHelper openHelper = new PersonSQLiteOpenHelper(getContext());
        SQLiteDatabase db = openHelper.getWritableDatabase();

        if(db.isOpen()) {

            try {
                // 开启事务
                db.beginTransaction();

                // 1. 从张三账户中扣1000块钱
                db.execSQL("update person set balance = balance - 1000 where name = 'zhangsan';");

                // ATM机, 挂掉了.
                // int result = 10 / 0;

                // 2. 向李四账户中加1000块钱
                db.execSQL("update person set balance = balance + 1000 where name = 'lisi';");

                // 标记事务成功
                db.setTransactionSuccessful();
            } finally {
                // 停止事务
                db.endTransaction();
            }
            db.close();
        }
    }

    public void testTransactionInsert() {
        PersonSQLiteOpenHelper openHelper = new PersonSQLiteOpenHelper(getContext());
        SQLiteDatabase db = openHelper.getWritableDatabase();

        if(db.isOpen()) {

            // 1. 记住当前的时间
            long start = System.currentTimeMillis();

            // 2. 开始添加数据
            try {
                db.beginTransaction();
                for (int i = 0; i < 10000; i++) {
                    db.execSQL("insert into person(name, age, balance) values('wang" + i + "', " + (10 + i) + ", " + (10000 + i) + ")");
                }
                db.setTransactionSuccessful();
            } finally {
                db.endTransaction();
            }

            // 3. 记住结束时间, 计算耗时时间
            long end = System.currentTimeMillis();

            long diff = end - start;
            Log.i(TAG, "耗时: " + diff + "毫秒");

            db.close();
        }
    }
}