c# - PostgreSQL:函数返回多个记录集:如何在 C# 中读取？

Question

使用这个链接 http://www.sqlines.com/postgresql/npgsql_cs_result_sets 我已经创建了示例，但它不起作用: 这是我的功能:

 CREATE OR REPLACE FUNCTION show_cities_multiple() 
 RETURNS SETOF refcursor AS $$
    DECLARE
      ref1 refcursor; 
      ref2 refcursor;                             
    BEGIN
      OPEN ref1 FOR SELECT user_id, user_name FROM users;
      RETURN NEXT ref1; 

      OPEN ref2 FOR SELECT id, company FROM customers;
      RETURN NEXT ref2;      
    END;
    $$ LANGUAGE plpgsql;

第一个循环仅读取记录集名称，这就是我可以从函数中读取的所有内容。

         NpgsqlConnection conn = new NpgsqlConnection(GetConnectionString());
                conn.Open();
                NpgsqlTransaction tran = conn.BeginTransaction();
                NpgsqlCommand command = new NpgsqlCommand("show_cities_multiple", conn);
                command.CommandType = CommandType.StoredProcedure;
                NpgsqlDataReader dr = command.ExecuteReader();
                while (dr.Read())
                {
                   Console.Write("{0}\n", dr[0]);
                }
// ----------there is output - only names of cursors recordsets
// <unnamed portal 1>
// <unnamed portal 2>

                dr.NextResult(); 
// But there is nothing to read, no additional recordsets
                while (dr.Read())
                    Console.Write("{0}\t{1} \n", dr[0], dr[1]);

                tran.Commit();
                conn.Close();

怎么了？如何从 PGSQL 函数读取多个记录集？

Answer 1

有几种方法可以针对不同的版本使用游标

how can I get cursor data with calling stored procedure in npgsql