Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Here's the code from <a href="https://stackoverflow.com/a/5047373/4794">Marc Gravell's answer</a>, along with an example of using it.</p> <pre><code>using System; using System.Collections.Generic; using System.Linq; public static class Utils { public static bool IsAny&lt;T&gt;(this IEnumerable&lt;T&gt; data) { return data != null &amp;&amp; data.Any(); } } class Program { static void Main(string[] args) { IEnumerable&lt;string&gt; items; //items = null; //items = new String[0]; items = new String[] { "foo", "bar", "baz" }; /*** Example Starts Here ***/ if (items.IsAny()) { foreach (var item in items) { Console.WriteLine(item); } } else { Console.WriteLine("No items."); } } } </code></pre> <p>As he says, not all sequences are repeatable, so that code may sometimes cause problems, because <code>IsAny()</code> starts stepping through the sequence. I suspect what <a href="https://stackoverflow.com/a/5047375/4794">Robert Harvey's answer</a> meant was that you often don't need to check for <code>null</code> <em>and</em> empty. Often, you can just check for null and then use <code>foreach</code>.</p> <p>To avoid starting the sequence twice and take advantage of <code>foreach</code>, I just wrote some code like this:</p> <pre><code>using System; using System.Collections.Generic; using System.Linq; class Program { static void Main(string[] args) { IEnumerable&lt;string&gt; items; //items = null; //items = new String[0]; items = new String[] { "foo", "bar", "baz" }; /*** Example Starts Here ***/ bool isEmpty = true; if (items != null) { foreach (var item in items) { isEmpty = false; Console.WriteLine(item); } } if (isEmpty) { Console.WriteLine("No items."); } } } </code></pre> <p>I guess the extension method saves you a couple of lines of typing, but this code seems clearer to me. I suspect that some developers wouldn't immediately realize that <code>IsAny(items)</code> will actually start stepping through the sequence. (Of course if you're using a lot of sequences, you quickly learn to think about what steps through them.)</p>
    singulars
    1. This table or related slice is empty.
    1. POHow to check if IEnumerable is null or empty?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USCommunity
    1. USDon Kirkby
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COIf you call IsAny on a null, it will throw an exception
      singulars
      1. PO
      1. USAce Trajkov
    2. CODid you try it, @Ace? It looks like it would throw an exception, but [extension methods can be called on null instances](http://stackoverflow.com/q/847209/4794).
      singulars
      1. PO
      1. USDon Kirkby
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload