请高手添加注释,帮忙解答疑惑!
using System;
using System.Data.SqlClient;
using System.Data;
using System.Collections.Generic;namespace kms.Models
{
public class CategoryModel:BaseModel
{
protected string tablename = "category"; public int id; public string category_name; public List<CategoryModel> list()
{
string sql = "SELECT id,category_name FROM " + this.tablename + " ORDER BY id DESC";
SqlDataReader sdr = getReader(sql, null);
List<CategoryModel> flist = new List<CategoryModel>();
if (sdr.HasRows)
{
while (sdr.Read())
{
CategoryModel mm = new CategoryModel();
mm.id = Convert.ToInt32(sdr["id"].ToString());
mm.category_name = sdr["category_name"].ToString();
flist.Add(mm);
}
}
sdr.Close();
return flist;
} public void delete(int id)
{
string sql = "DELETE FROM " + this.tablename + " WHERE id=@id";
SqlParameter[] parArray = {
CommonLb.makeParam("@id",SqlDbType.Int,id)
};
excuteQuery(sql, parArray);
} public int add(string category_name)
{
string sql = "INSERT INTO " + this.tablename + "(category_name) VALUES(@category_name)";
SqlParameter[] parArray = {
CommonLb.makeParam("@category_name",SqlDbType.NVarChar,category_name)
};
return excuteQuery(sql, parArray);
}
public CategoryModel getOne(int id)
{
if (id <= 0)
return null;
CategoryModel mm = new CategoryModel();
SqlParameter[] parArray = {
CommonLb.makeParam("@id",SqlDbType.Int,id)
};
string sql = "SELECT TOP 1 id,category_name FROM " + this.tablename + " WHERE id=@id";
SqlDataReader sdr = getReader(sql, parArray);
if (sdr.HasRows)
{
sdr.Read();
mm.category_name = sdr["category_name"].ToString();
mm.id = Convert.ToInt32(sdr["id"].ToString());
}
sdr.Close();
return mm;
}
public int update(int id, string category_name)
{
string sql = "UPDATE " + this.tablename + " SET category_name=@category_name WHERE id=@id";
SqlParameter[] parArray = {
CommonLb.makeParam("@category_name",SqlDbType.NVarChar,category_name),
CommonLb.makeParam("@id",SqlDbType.Int,id)
};
return excuteQuery(sql, parArray);
}
}
}
using System;
using System.Data.SqlClient;
using System.Data;
using System.Collections.Generic;namespace kms.Models
{
public class CategoryModel:BaseModel
{
protected string tablename = "category"; public int id; public string category_name; public List<CategoryModel> list()
{
string sql = "SELECT id,category_name FROM " + this.tablename + " ORDER BY id DESC";
SqlDataReader sdr = getReader(sql, null);
List<CategoryModel> flist = new List<CategoryModel>();
if (sdr.HasRows)
{
while (sdr.Read())
{
CategoryModel mm = new CategoryModel();
mm.id = Convert.ToInt32(sdr["id"].ToString());
mm.category_name = sdr["category_name"].ToString();
flist.Add(mm);
}
}
sdr.Close();
return flist;
} public void delete(int id)
{
string sql = "DELETE FROM " + this.tablename + " WHERE id=@id";
SqlParameter[] parArray = {
CommonLb.makeParam("@id",SqlDbType.Int,id)
};
excuteQuery(sql, parArray);
} public int add(string category_name)
{
string sql = "INSERT INTO " + this.tablename + "(category_name) VALUES(@category_name)";
SqlParameter[] parArray = {
CommonLb.makeParam("@category_name",SqlDbType.NVarChar,category_name)
};
return excuteQuery(sql, parArray);
}
public CategoryModel getOne(int id)
{
if (id <= 0)
return null;
CategoryModel mm = new CategoryModel();
SqlParameter[] parArray = {
CommonLb.makeParam("@id",SqlDbType.Int,id)
};
string sql = "SELECT TOP 1 id,category_name FROM " + this.tablename + " WHERE id=@id";
SqlDataReader sdr = getReader(sql, parArray);
if (sdr.HasRows)
{
sdr.Read();
mm.category_name = sdr["category_name"].ToString();
mm.id = Convert.ToInt32(sdr["id"].ToString());
}
sdr.Close();
return mm;
}
public int update(int id, string category_name)
{
string sql = "UPDATE " + this.tablename + " SET category_name=@category_name WHERE id=@id";
SqlParameter[] parArray = {
CommonLb.makeParam("@category_name",SqlDbType.NVarChar,category_name),
CommonLb.makeParam("@id",SqlDbType.Int,id)
};
return excuteQuery(sql, parArray);
}
}
}
其中几个类的用法明白后,你就知道这断代码是什么意思了。
using System.Data.SqlClient;
using System.Data;
using System.Collections.Generic;namespace kms.Models
{
public class CategoryModel : BaseModel
{
protected string tablename = "category"; public int id; public string category_name; public List<CategoryModel> list()//返回泛型集合(这个集合中的数据类型也是自定义的,CategoryModel,可以是个结构)的方法,
//查找id、category_name.
{
string sql = "SELECT id,category_name FROM " + this.tablename + " ORDER BY id DESC";
SqlDataReader sdr = getReader(sql, null);
List<CategoryModel> flist = new List<CategoryModel>();
if (sdr.HasRows)
{
while (sdr.Read())
{
CategoryModel mm = new CategoryModel();//CategoryModel 中至少有id 、category_name 两个成员
mm.id = Convert.ToInt32(sdr["id"].ToString());
mm.category_name = sdr["category_name"].ToString();
flist.Add(mm);
}
}
sdr.Close();
return flist;
} public void delete(int id)//删除id方法, 带参数(id)的sql命令
{
string sql = "DELETE FROM " + this.tablename + " WHERE id=@id";
SqlParameter[] parArray = {
CommonLb.makeParam("@id",SqlDbType.Int,id)
};
excuteQuery(sql, parArray);
} public int add(string category_name)//添加种类名
{
string sql = "INSERT INTO " + this.tablename + "(category_name) VALUES(@category_name)";
SqlParameter[] parArray = {
CommonLb.makeParam("@category_name",SqlDbType.NVarChar,category_name)
};
return excuteQuery(sql, parArray);
}
public CategoryModel getOne(int id)//根据 id号查找并返回第一条符合条件的CategoryModel类型的数据
{
if (id <= 0)
return null;
CategoryModel mm = new CategoryModel();
SqlParameter[] parArray = {
CommonLb.makeParam("@id",SqlDbType.Int,id)
};
string sql = "SELECT TOP 1 id,category_name FROM " + this.tablename + " WHERE id=@id";
SqlDataReader sdr = getReader(sql, parArray);
if (sdr.HasRows)
{
sdr.Read();
mm.category_name = sdr["category_name"].ToString();
mm.id = Convert.ToInt32(sdr["id"].ToString());
}
sdr.Close();
return mm;
}
public int update(int id, string category_name)// 更新根据参数id、category_name 更新记录
{
string sql = "UPDATE " + this.tablename + " SET category_name=@category_name WHERE id=@id";
SqlParameter[] parArray = {
CommonLb.makeParam("@category_name",SqlDbType.NVarChar,category_name),
CommonLb.makeParam("@id",SqlDbType.Int,id)
};
return excuteQuery(sql, parArray);
}
}
}
//楼主可能要了解学习的是 c#中的sql操作。看书学习吧。