不能隐式地将类型'int'转换为'system.data.dataset' [英] cannot implicitly convert type 'int' to 'system.data.dataset'

问题描述

大家好，我需要你的帮助，我正在尝试执行查询并将所有检索到的数据放入数据集中，但我得到此错误无法将类型'int'隐式转换为'system.data.dataset '。

这是代码

Hi all, pls i need your help, i am trying to execute a query and put all the retrieved data in a data set, but i get this error " cannot implicitly convert type 'int' to 'system.data.dataset'".
Here's the code

String Astra_conn = ConfigurationManager.ConnectionStrings["AstraSeverConnection"].ConnectionString;

System.Text.StringBuilder sql = new System.Text.StringBuilder();

这是一小段sql

this is a small piece of the sql

sql.Append(" SELECT ROWNUM AS ID, institution, LPAD (a.zone_name, 3, '0') AS campus, ");
sql.Append(" term_name AS term, student_instance_id AS student_id, subject, course, ");
sql.Append(" section_name AS section_num, offering AS title, ");

它的OracleConnection因为它是Oracle服务器，否则就是SqlConnection。

Its OracleConnection because it is an Oracle server otherwise, it would be SqlConnection.

DataSet rs = new DataSet();
   OracleConnection Astra_db_Conn = new OracleConnection(Astra_conn);
   string myquery = sql.ToString();
   OracleCommand cmd = new OracleCommand(myquery);

   Astra_db_Conn.Open();
   try
   {
       SqlDataAdapter adpt = new SqlDataAdapter();
       rs = cmd.ExecuteNonQuery(); // this is where is get the error.
       adpt.Fill(rs);

   }
   catch(Exception e)
   {
  log.Error("*** ERROR *** IRISExportQueries.loadStudentInfoLearningSites():" + e);

   }

我也试过

Astra_db_Conn.Open（）;

I have also tried
Astra_db_Conn.Open();

 try
 {
     SqlDataReader reader = new SqlDataAdapter();
     reader = cmd.ExecuteNonQuery(); // this is where is get the error.
 

 }
 catch(Exception e)
 {
log.Error(&quot;*** ERROR *** IRISExportQueries.loadStudentInfoLearningSites():&quot; + e);</pre>

 }

然后我得到错误：无法隐式转换类型'int'到'System.Data.SqlClient.SqlDataReader'。



非常感谢您的帮助。

But then i get the error: "cannot implicitly convert type 'int' to 'System.Data.SqlClient.SqlDataReader'".

Thanks your help will be very much appreciated.

推荐答案

ExecuteNonQuery返回受操作影响的行数/记录数的整数。您需要使用ExecuteReader而不是使用ExecuteNonQuery。



ExecuteNonQuery - >主要用于更新，插入和删除。

ExecuteReader - >返回一个可以为Select语句加载记录的数据阅读器。

ExecuteScalar - >返回查询返回的第一个记录的第一列。用于计数，平均等

ExecuteNonQuery returns an integer of the number of rows/records affected by the operation. Instead of using ExecuteNonQuery you need to use ExecuteReader.

ExecuteNonQuery -> Used for Updates, Inserts and Deletes mostly.
ExecuteReader -> Returns a data reader that can load records, for Select statements.
ExecuteScalar -> Returns the first column of the first record returned by the query. Useful for counting, averaging, etc.

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