Test.java:
/** * 本例解决的问题: * 核心问题:通过SQLiteOpenHelper类创建数据库对象 * 通过数据库对象对数据库的数据的操作 * 1.sql语句方式操作SQLite数据库 * 2.谷歌提供的api对SQLite数据库的操作 * 3.SQLite对事务的操作 */ import com.ghsy.createsqlitedb.db.MyOpenHelper; import android.content.ContentValues; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.test.AndroidTestCase; public class Test extends AndroidTestCase { MyOpenHelper oh; SQLiteDatabase db; public void test() { // 创建一个MyOpenHelper对象 // 修改此处的版本号,会执行upgrade方法--upgrade方法中添加了一列 MyOpenHelper oh = new MyOpenHelper(getContext(), "people.db", null, 3); // 如果数据库不存在,先创建数据库,再打开数据库,如果已经存在,直接打开 SQLiteDatabase db = oh.getWritableDatabase(); db.close(); } // 测试框架初始化完成 /** * This method is called before a test is executed */ @Override protected void setUp() throws Exception { // TODO Auto-generated method stub super.setUp(); oh = new MyOpenHelper(getContext(), "people.db", null, 3); db = oh.getWritableDatabase(); } // ===========sql语句方式操作SQLite数据库================================ public void insert() { db.execSQL("insert into person(name, phone, money) values(?, ?, ?)", new Object[] { "大明", "18666", 6000 }); db.execSQL("insert into person(name, phone, money) values(?, ?, ?)", new Object[] { "小红", "18666", 6000 }); db.execSQL("insert into person(name, phone, money) values(?, ?, ?)", new Object[] { "大红", "18666", 6000 }); } public void delete() { db.execSQL("delete from person where name = ?", new Object[] { "大明" }); } public void update() { db.execSQL("update person set money = 10000 where name = ?", new Object[] { "小明" }); } public void query() { // 游标,存放查询返回的数据,获取方法跟resultSet高度雷同 Cursor c = db.rawQuery("select * from person", new String[] {}); while (c.moveToNext()) { String name = c.getString(c.getColumnIndex("name")); String phone = c.getString(c.getColumnIndex("phone")); System.out.println(name + ";" + phone); } } // ==============谷歌提供的api对SQLite数据库的操作====================== /** * api-insert data to table */ public void insertApi() { ContentValues cv = new ContentValues(); cv.put("name", "微明"); cv.put("phone", 15666); cv.put("money", 630); long id = db.insert("person", null, cv); System.out.println(id); } /** * api-delete data from table * * @return the number of rows affected */ public int deleteApi() { int affectedNum = db.delete("person", "name=?", new String[] { "小红" }); return affectedNum; } /** * api-update */ public void updateApi() { ContentValues contentValues = new ContentValues(); contentValues.put("name", "小红"); contentValues.put("money", "10"); // return the number of rows affected db.update("person", contentValues, "name=?", new String[] { "大红" }); } public void queryApi() { Cursor cursor = db.query("person", new String[] { "phone", "money" }, null, null, null, null, null); while (cursor.moveToNext()) { String phone = cursor.getString(cursor.getColumnIndex("phone")); String money = cursor.getString(cursor.getColumnIndex("money")); System.out.println(phone + "##" + money); } } // ===============SQLite对事务的操作===================== /** * 银行转账操作 */ public void transation(){ db.beginTransaction(); try { //name为微明的用户向小红转账 ContentValues contentValues=new ContentValues(); contentValues.put("money", 1000); db.update("person", contentValues, "name=?", new String[]{"微明"}); ContentValues contentValues2=new ContentValues(); contentValues2.put("money", 1100); db.update("person", contentValues2, "name=?", new String[]{"小红"}); //所有语句执行完毕,若没有异常,则会执行这句设置事务成功的标记 db.setTransactionSuccessful(); } finally { //会检查事务的标识,若没有调用setTransactionSuccessful()方法设置标志,则回滚事务。否则提交事务。 db.endTransaction(); } } }
MyOpenHelper.java
**SQLiteOpenHelper: * A helper class to manage database creation and version management. * 所以,SQLiteOpenHelper是对库本身的操作。若要对库中数据操作,需要使用库对象的方法。 */ import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.database.sqlite.SQLiteOpenHelper; public class MyOpenHelper extends SQLiteOpenHelper { //name:数据库文件的名字 //factory:游标工厂 //version:版本,必须大于等于1 public MyOpenHelper(Context context, String name, CursorFactory factory, int version) { super(context, name, factory, version); // TODO Auto-generated constructor stub } //数据库创建时调用 @Override public void onCreate(SQLiteDatabase db) { //创建一个person表 db.execSQL("create table person(_id integer primary key autoincrement, name char(10), phone char(20))"); System.out.println("oncreate调用了"); } //数据库升级时调用 @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // TODO Auto-generated method stub System.out.println("onupgrade调用了"); db.execSQL("alter table person add money char(20)"); } }
Android数据的四种存储方式之SQLite数据库
时间: 2024-10-23 06:06:37