C#三层架构第四课之DAL层
DAL层的方法基本与BLL层一致，前期可以这么做，简单易于理解，后期BLL一个方法可能包含若干个DAL的方法。参考代码如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Model;
using System.Data.SqlClient;
using System.Data;
//DAL层调用公共的类库
using DbUtil;
using IDAL;
namespace DAL
{
public class DeptDao:IDept
{
//1.复制 service层的几个方法;
//CRUD:增加U：修改D：删除；R:检索;
public bool addDept(Dept dept)
{
String sql = "insert dept values(@deptId,@deptName)";
SqlParameter(参数名,值),这里通过封装好的dept对象来取值
//cmd.Parameters.Add(new SqlParameter("@deptId",dept.DeptId));
//cmd.Parameters.Add(new SqlParameter("@deptName", dept.DeptName));
List<SqlParameter> parameters = new List<SqlParameter>();
//问题转移为如何向集合parameters,增加参数和值;
parameters.Add(new SqlParameter("@deptId", dept.DeptId));
parameters.Add(new SqlParameter("@deptName", dept.DeptName));
return DBHelper.update(sql,parameters);
}
public bool updateDept(Dept dept)
{
String sql = "update dept set deptName=@deptName where deptId=@deptId";
List<SqlParameter> parameters = new List<SqlParameter>();
parameters.Add(new SqlParameter("@deptName",dept.DeptName));
parameters.Add(new SqlParameter("@deptId",dept.DeptId));
return DBHelper.update(sql,parameters);
}
public bool delDept(Dept dept)
{
String sql = "delete from dept where deptid=@deptId";
List<SqlParameter> parameters = new List<SqlParameter>();
parameters.Add(new SqlParameter("@deptId", dept.DeptId));
return DBHelper.update(sql, parameters); ;
}
public DataTable refreshData() {
String sql = "select deptId 部门编号,deptName 部门名称 from dept";
return DBHelper.query(sql,null);
}
public DataTable findDeptByName(String deptName)
{
String url = "server=.;database=MyDb;uid=sa;pwd=123456";
//1.链接对象;
SqlConnection conn = new SqlConnection(url);
conn.Open();
//2.SqlCommand
SqlCommand cmd = conn.CreateCommand();
//String sql = "select * from dept where deptName like '{0}' ",deptName;
String sql = "select deptId 部门编号,deptName 部门名称 from dept where deptName like @deptName";
cmd.CommandText = sql;
String str = "%" + deptName + "%";
cmd.Parameters.Add(new SqlParameter("@deptName",str));
//需要用到适配器对象;适配器没有这种参数方式
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = cmd;
DataTable dt=new DataTable();
da.Fill(dt);
return dt;
}
}
}
文档来源：51CTO技术博客https://blog.51cto.com/u_2096101/3185703
页:
[1]