函数增删改查数据库

package com.bwei.acid.dao;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import com.bwei.acid.db.MySqliteOpenHelper;

public class StudentDao {

	private MySqliteOpenHelper helper;

	public StudentDao(Context context) {

		helper = new MySqliteOpenHelper(context);
	}

	// 增加
	public void add(String name, int age) {

		SQLiteDatabase db = helper.getWritableDatabase();
		ContentValues values = new ContentValues();
		values.put("name", name);
		values.put("age", age);
		
		/**
		 * 第一个参数表明
		 * 第二个参数是列
		 */
		db.insert("student", null, values );

		db.close();
	}

	// 删除
	public void delete(String name) {
		
		SQLiteDatabase db = helper.getWritableDatabase();
		db.delete("student", "name=?", new String[]{name});
		
		db.close();

	}

	// 修改
	public void update(String name) {
		SQLiteDatabase db = helper.getWritableDatabase();
		
		ContentValues values = new ContentValues();
		
		values.put("name", name);
		values.put("age", 888);
	
		db.update("student", values , "name=?", new String[]{name});
		db.close();
		
	}

	// 查询
	public void query() {
		SQLiteDatabase db = helper.getWritableDatabase();
		/**
		 * Table 表名 
			Columens 要查询的列
			Selection 查询条件
			selectionArgs 查询条件占位符对应的内容
			groupBy 分组判断条件
			Having 是否含有的判断条件
			orderBy  排序判断条件
			Limit  分页查询判断条件
		 */
		
		Cursor cursor = db.query("student", null, null,
				null, null, 
				null, null, null);
		
		while(cursor.moveToNext()){
			String name = cursor.getString(cursor.getColumnIndex("name"));
			int age = cursor.getInt(cursor.getColumnIndex("age"));
			
			System.out.println("name="+name+",age="+age);
		}
		
	}

}