android下数据库的增删改查

在android应用程序中使用db.execSQL(“sql”,bindArgs)操作增删改查语句；
1、创建表结构
public void create(View v){

        db.execSQL("create table person (id integer primary key autoincrement,name varchar(20))", new Object[]{});
        Toast.makeText(this, "创建表结构成功", 0).show();

    }

2、插入

    public void insert(View v){

            db.execSQL("insert into person (name)values(?)", new String[]{"lisi"});
            Toast.makeText(this, "插入数据成功", 0).show();
        }

3、查询：db.rawQuery，cursor类似于一个指针，当cursor指向一条记录时，就把当前记录的数据封装到cursor中，直接从cursor取数据

    public void query(View v){

      Cursor cursor = db.rawQuery("select * from person",null);
      //移动游标，返回值为true表示没有移动到数据集的最后（空），如果为false已经数据集的最后（没有数据了）
      while(cursor.moveToNext()){
         int id = cursor.getInt(0);
         String name = cursor.getString(1);

         System.out.println("id="+id+"; name="+name);
      }

      Toast.makeText(this, "查询数据成功", 0).show();
    }

4、更新
  public void update(View v){

        db.execSQL("update person set name='wangwu' where id=?", new Object[]{1});
        Toast.makeText(this, "更新数据成功", 0).show();

    }
4、删除

  public void delete(View v){

        db.execSQL("delete from person where id=?", new Object[]{1});
        Toast.makeText(this, "删除数据成功", 0).show();

    }

数据库的另外一种增删改查方法:

使用google提供的另外一种方式操作数据库表：

1、插入数据
public void insert(View v){

//db.execSQL("insert into person (name)values(?)", new String[]{"lisi"});
  ContentValues values = new ContentValues();
  Random r = new Random();
  values.put("name", "zhangsan"+r.nextInt(100));
   long rowId =  db.insert("person", null, values);
  System.out.println("rowId="+rowId);
    Toast.makeText(this, "插入数据成功", 0).show();
}

2、查询数据
public void query(View v){
/**
* table 表名
* columns 查询的列
* selection 查询条件”id=1”
* selectionArgs 查询条件的值
* String groupBy
* String having
* String orderBy
*
*/
Cursor cursor = db.query(“person”, new String[]{“id”,”name” }, null, null, null, null, null);

  while(cursor.moveToNext()){
     int id = cursor.getInt(0);
     String name = cursor.getString(1);

     System.out.println("id="+id+"; name="+name);
  }

  Toast.makeText(this, "查询数据成功", 0).show();
}

public void update(View v){

//      db.execSQL("update person set name='wangwu' where id=?", new Object[]{1});
//用来封装要修改的列名和值
  ContentValues values = new ContentValues();
  values.put("name", "wangwu");
  db.update("person", values, "id=?", new String[]{"1"});
  Toast.makeText(this, "更新数据成功", 0).show();

}

public void delete(View v){

// db.execSQL(“delete from person where id=?”, new Object[]{1});
db.delete(“person”, “id=?”, new String[]{“2”});
Toast.makeText(this, “删除数据成功”, 0).show();

}