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これをグーグルで調べたところ、SQL選択クエリをキー値ペアリストにロードする方法を参照している場所が見つからないようです。

 {
Keyvaluepair<int, name> D =new keyvaluepair <Int, name>

Using (db2connection conn =new db2connection())
 {
   Db2command cms =new db2command();

String select=    ( @"Select distinct Value, Descrip
      From cool", conn)
   Using(db2reader read =new db2reader())
  {

    }
 }

}

クエリを実行した後、値と Descrip を keyvaluepair リストにロードするにはどうすればよいですか。キー値ペア

4

1 に答える 1

4

You haven't mentioned what technology you're using to execute the query, so I'll assume you're using a basic technology that doesn't automatically map to classes.

It's fairly easy to do. All you do is this:

  1. Iterate over every row you received
  2. Create a new KeyValuePair object with the types appropriate to the columns (typically this is string, string or int, string)
  3. Set the values of the KeyValuePair to the values of each column you read from the reader.
  4. If you want to do something else with the KeyValuePair later, try adding it to a List<KeyValuePair> during the iteration

Edit Ok, so based on your edits, I'm guessing you're new to the whole thing. You mentioned you're using DB2. You haven't been explicit as to which library you're using to read from DB2, so I'm going to assume it's the library provided by IBM. I'll provide information based on the DB2DataReader class documentation from IBM.

The following should work (provided I haven't typoed). I've included comments to help along the way:

// this variable will have the data read from the server after all is said and done
List<KeyValuePair<int, string>>> data = new List<KeyValuePair<int, string>>();

// create the connection (replace connection string as necessary)
using (DB2Connection conn = new DB2Connection("database connection string"))
{
    // specify the query, create and open the command object 
    string qry = "Select distinct Value, Descrip from cool";
    DB2Command cmd = new DB2Command(qry, conn);
    conn.Open();

    // calling ExecuteReader() sends the query to the database and starts 
    // the process of reading the data
    using(DB2DataReader read = cmd.ExecuteReader())
    {
        // you have to call Read() for every row. It will return false if there 
        // are no more rows left
        while(read.Read())
        {
            // calling the various Get methods is how you get the data out of the reader
            // note that you pass in the index of the column for each call
            int intVal = read.GetInt32(0);
            string strVal = read.GetString(1);

            // now you're ready to create your KeyValuePair object
            KeyValuePair<int, string> tmp = new KeyVauePair<int, string>(intVal, strVal);

            // And add it to the list we defined at the start of this
            data.Add(tmp);
        }
    }
}

// and now we've got all of the data from your query wrapped up into a nice list
// called 'data'. Do with it whatever you planned
于 2012-11-09T16:16:54.823 に答える