Question

我需要保存一个sql SELECT语句，该语句包括数据库中的所有表及其列。该语句工作正常，我可以从所需的表和列中获取所有名称。

结果如下：（这只是伪东西）

            table_Name  Column_name
            - CallerIP  DT
            - CallerIP  ID
            - CallerIP  IP
            - queueObject Action
            - queueObject Attempt
            - queueObject DestinationAddress
            - queueObject ID

我可以将其保存到Dictionary中，其中tableName是String，而Colum_Names是List中Strings的

private Dictionary<string, List<string>> rowAndTables = new Dictionary<string, List<string>>();

这是我的代码，应将所有表和行添加到字典中

        //Some code above, that doesnt matter here
        command = new SqlCommand(sqlSelect, SqlConnector.getConnection());
        command.Connection = SqlConnector.getConnection();
        reader = command.ExecuteReader();

        while (reader.Read()) {
            if (tempTableName.Equals(reader.GetString(0)) == false) {
                tempTableName = reader.GetString(0);
                tempColumn = reader.GetString(1);
                Console.WriteLine(tempTableName);
                Console.WriteLine(tempColumn);
            } else {
                tempColumn = reader.GetString(1);
                Console.WriteLine(tempColumn);
            }

        }

除了打印所有表和列之外，这没有任何作用。结果如下： //控制台...

CallerIP //Table
DT
ID
IP
queue_object //Table
Action
Attempt
DestinationAddress
ID

所以打印很好。现在，我正在努力将其添加到Dictionary中。有人可以帮忙吗？我想我所做的任何事都没有道理，只会使任何人感到困惑。

Answer 1

好吧，如果您想填写字典

private Dictionary<string, List<string>> rowAndTables = 
  new Dictionary<string, List<string>>();

您应该稍微修改代码：

    ...

    //DONE: wrap IDisposable (command) into using in order to release resources
    using (var command = new SqlCommand(sqlSelect, SqlConnector.getConnection())) {
      // Redundant, can be dropped
      command.Connection = SqlConnector.getConnection();

      using (var reader = command.ExecuteReader()) {
        //TODO: check if the key and value are correct ones 
        string key = Convert.ToString(reader[0]);
        string value = Convert.ToString(reader[1]);

        // Do we have the key (and corresponding list) in the dictionary?
        if (rowAndTables.TryGetValue(key, out var list))  
          // yes - we should add the value to the existing list 
          list.Add(value); 
        else 
          // no - we have to create key and list with value 
          rowAndTables.Add(key, new List<string>() {value}); 
      }
    }

将具有所有表和列名称的SQL语句添加到Dictionary中

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