android 进程间数据库读取 android数据库查询语句

1、创建openhelper类

public class MyOpenHelper extends SQLiteOpenHelper {
public MyOpenHelper(Context context) {
super(context, "student.db", null, 3);
}@Override
public void onCreate(SQLiteDatabase db) {


        db.execSQL("create table person (_id integer primary key autoincrement,name char(10),phone char(10),salary integer(10))");
}

2、重新实例化MyOpenHelper对象，获取数据库

//实例化openhelper对象

       SQLiteDatabase db=oh.getWritableDatabase();       //获取数据库       db.execSQL("insert into person(name,phone,salary)values(?,?,?) ",new Object[]                     {"李四","158666",8000});
       db.close();

3、常用的数据库语句

  （1）创建表

create table person(_id integer primary key autoincrement,name char(10),phone           char(20),salary char(10))

   （2）添加

"insert into person(name,phone,salary)valuses(?,?,?)",new object[]{"张                        三","18668758",8000}

    (3)删除

delete from person where name ='张三'；

(4) 更新
    update person set salary =10800 where name ='王五';

    （5）查询

 

public void select(){

    oh=new MyOpenHelper(getContext());

    db=oh.getWritableDatabase();

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

    while (cursor.moveToNext()) {
String name=cursor.getString(0);  //
int salary=cursor.getInt(1);   //1对应查询语句中salary的位置
System.out.println(name+"的薪资是"+salary);
}

    db.close();

    }