Oracle+Ado.Net(四)

概要:

       1.改动BaseModel

       2.补充一些重载方法,稍微改动了一下原有代码:GetAllToList()改为GetAllToListBySql();

       3.存储过程分页实现

       4.客户端拼接sql分页实现

       在BaseModel中添加一下几个属性字段用于分页:

        /// <summary>
        /// 分页查询条件
        /// </summary>
        private string where="";

        public string Where
        {
            get { return where; }
            set { where = value; }
        }
        /// <summary>
        /// 分页查询字段列
        /// </summary>
        private string fileds = "*";

        public string Fileds
        {
            get { return fileds; }
            set { fileds = value; }
        }

        private int pageIndex = 1;

        public int PageIndex
        {
            get { return pageIndex; }
            set { pageIndex = value; }
        }

        private int pageSize = 2;

        public int PageSize
        {
            get { return pageSize; }
            set { pageSize = value; }
        }

        private string orderField = "";

        public string OrderField
        {
            get { return orderField; }
            set { orderField = value; }
        }
        /// <summary>
        /// 升序为0,降序为1
        /// </summary>
        private int orderFlag = 0;

        public int OrderFlag
        {
            get { return orderFlag; }
            set { orderFlag = value; }
        }
        /// <summary>
        /// 总条数
        /// </summary>
        private int totalCount;

        public int TotalCount
        {
            get { return totalCount; }
            set { totalCount=value ; }
        }
        /// <summary>
        /// 总页数
        /// </summary>
        private int totalPage;

        public int TotalPage
        {
            get { return totalPage; }
            set { totalPage=value; }
        }

        /// <summary>
        /// 返回的数据
        /// </summary>
        private DataTable result;

        public DataTable Result
        {
            get { return result; }
            set {  result=value; }
        }

 2.重载部分:

 GetAllListToList()的重载方法签名如下:

 public virtual List<T> GetAllToList(IDataReader dr)

 public virtual List<T> GetAllToList(string strWhere, int PageSize, int PageIndex, int OrderFlag, string colList, string fldOrder, string tblName)

 ......

3.存储过程实现分页

存储过程为:

--创建包

create or replace package testpackage as
type test_cursor is ref cursor;
end testpackage;

--存储过程

create or replace procedure fenye
(
       tableName in varchar2, --表名
       fields in varchar2,    --查询结果显示字段
       wherecase in varchar2, --查询条件
       pageSize in number,  --一页显示记录数
       pageNow in number,   --当前页
       orderField  varchar2, --排序字段，为空表示不排序
       orderFlag number,     --排序标识 0：正序 1：倒序
       myrows out number,   --总记录数
       myPageCount out number, --总分页
       p_cursor out testpackage.test_cursor     --返回的记录集
) is
--定义部分
--定义sql语句字符串
v_sql varchar2(1000);
--定义两个整数
v_begin number:=(pageNow-1)*pagesize+1; --开始记录
v_end number:=pageNow*pageSize;         --结束记录
--排序sql
v_orderSql varchar2(100):='';
v_wherecase varchar2(100):='';
begin
  --执行部分
  --如果orderField不为空，则进行排序，如果orderFlag=0为升序，1为降序
  if orderField is not null then
    if orderFlag=0 then
      v_orderSql:=' order by '||orderField;
    elsif orderFlag=1 then
      v_orderSql:=' order by '||orderField||' desc';
    else
      null;
    end if;
  end if;
  --条件判断语句
  if wherecase is not null then
    v_wherecase:=' where '||wherecase;
  end if;
  v_sql:='select * from
          (select t1.* ,rownum rn from(select '|| fields ||' from '|| tableName|| v_wherecase ||' '||v_orderSql ||') t1 where rownum<='|| v_end ||')
          where rn>='|| v_begin;
  --把游标和sql关联
  open p_cursor for v_sql;
  --计算myrows和myPageCount
  --组织一个sql
  v_sql:='select count(*) from '|| tableName || v_wherecase || ' ' ||v_orderSql;
  --执行sql,并把返回的值赋给myrows;
  execute immediate v_sql into myrows;
  --计算myPageCount
  if mod(myrows,Pagesize)=0 then
    myPageCount:=myrows/Pagesize;
  else
    myPageCount:=myrows/pagesize+1;
  end if;
  --关闭游标
  --close p_cursor;
end;

在BaseDal的调用代码如下:

  public virtual List<T> GetDataByProcedure(T model, out int totalCount)
        {
            OracleConnection conn = DbAction.getConn();
            OracleCommand com = new OracleCommand();
            com.CommandText = "fenye";
            com.Connection = conn;
            com.CommandType = CommandType.StoredProcedure;
            OracleParameter[] ps = {
                                       new OracleParameter("tableName",OracleType.VarChar),
                                       new OracleParameter("fields",OracleType.VarChar),
                                       new OracleParameter("wherecase",OracleType.VarChar),
                                       new OracleParameter("pageSize",OracleType.Number),
                                       new OracleParameter("pageNow",OracleType.Number),
                                       new OracleParameter("orderField",OracleType.VarChar),
                                       new OracleParameter("orderFlag",OracleType.Number),
                                       new OracleParameter("myrows",OracleType.Number),
                                       new OracleParameter("myPageCount",OracleType.Number),
                                       new OracleParameter("p_cursor",OracleType.Cursor)
                                   };
            ps[0].Value = TableName;//注意这里两种情况1.在实体层手动输入tableName,然后调用model.TableName;2.直接在数据访问层中反射类名TableName
            ps[1].Value = model.Fileds;
            ps[2].Value = model.Where;
            ps[3].Value = model.PageSize;
            ps[4].Value = model.PageIndex;
            ps[5].Value = model.OrderField;
            ps[6].Value = model.OrderFlag;
            ps[7].Direction = ParameterDirection.Output;
            ps[8].Direction = ParameterDirection.Output;
            ps[9].Direction = ParameterDirection.Output;
            foreach (OracleParameter item in ps)
            {
                com.Parameters.Add(item);
            }
            OracleDataAdapter da = new OracleDataAdapter(com);
            DataSet ds = new DataSet();
            try
            {
                da.Fill(ds);
            }
            catch (Exception)
            {
                
                throw;
            }
            model.Result = ds.Tables[0];
            model.TotalCount = int.Parse(ps[7].Value.ToString());
            model.TotalPage = Convert.ToInt32(Math.Ceiling(Double.Parse(ps[8].Value.ToString())));
            totalCount = int.Parse(ps[7].Value.ToString());
            List<T> list = new List<T>();
            foreach (DataRow item in ds.Tables[0].Rows)
            {
                list.Add(GetModel(ds.Tables[0], item));
            }

            return list;
        }

Note:需要注意的几个问题是,

1.参数变量名必须和储存过程的变量名保持一样,

2.记得CommandType设置为存储过程,

3TableName如果取BaseModel则必须在调用之前手动指定表名;

4.客户端拼接sql实现分页

拼接sql的方法代码如下:

       public string BuildSql(string strWhere, int PageSize, int PageIndex, int OrderFlag, string colList, string fldOrder, string tblName)
        {
            //查询字段
            string sColList = "";
            if (string.IsNullOrEmpty(colList) || colList == "*")
            {
                PropertyInfo[] pis = typeof(T).GetProperties(BindingFlags.Instance | BindingFlags.DeclaredOnly | BindingFlags.Public);
                foreach (PropertyInfo pi in pis)
                {
                    sColList += "[" + pi.Name + "],";
                }
                sColList = sColList.Substring(0, sColList.Length - 1);
            }
            else
            {
                sColList = SqlAction.GetSQLFildList(colList);
            }
            StringBuilder strSql = new StringBuilder();
            string strOrder; //排序字段
            if (string.IsNullOrEmpty(fldOrder))
            {
                fldOrder = PrimaryKey;
            }//排序类型
            if (OrderFlag == 1)
            {
                strOrder = string.Format(" order by {0} desc", fldOrder);
            }
            else
            {
                strOrder = string.Format(" order by {0} asc", fldOrder);
            }
            //没有where 条件
            if (string.IsNullOrEmpty(strWhere))
            {
                strSql.Append(string.Format("select {0} from(select {1}, rownum as id from {2}  {3}",
                                            sColList, sColList, tblName, strOrder));
                strSql.Append(string.Format(") a  where id between {0} and {1}", (PageIndex - 1) * PageSize + 1,
                                            PageIndex * PageSize));
            }
            else
            {
                strSql.Append(string.Format("select {0} from(select {1}, rownum as id from {2} {3} ", sColList, sColList, tblName, strOrder));
                strSql.Append(string.Format(" where {0}", strWhere));
                strSql.Append(string.Format(") a  where id between {0} and {1}", (PageIndex - 1) * PageSize + 1,
                                            PageIndex * PageSize));
            }
            return strSql.ToString().Replace("[","").Replace("]","");
        }

        public IDataReader GetDataReaderByPage(string strWhere, int PageSize, int PageIndex, int OrderFlag, string colList, string fldOrder, string tblName)
        {
            string strSql = BuildSql(strWhere, PageSize, PageIndex, OrderFlag, colList, fldOrder, tblName);
            OracleConnection conn = DbAction.getConn();
            OracleCommand com = new OracleCommand(strSql, conn);
            conn.Open();
            IDataReader dr= com.ExecuteReader(CommandBehavior.CloseConnection);//使用using也可以
            return dr;
        }

        public virtual List<T> GetAllToList(string strWhere, int PageSize, int PageIndex, int OrderFlag, string colList, string fldOrder, string tblName)
        {
            //自托管
            using (IDataReader dr = GetDataReaderByPage(strWhere, PageSize, PageIndex, OrderFlag, colList, fldOrder, tblName))
            {
                return GetAllToList(dr);
            }
           
        }

至此,已经完成分页功能.