Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>My personal approach to this sort of things is to use <em>property maps</em>: I <a href="https://github.com/dietmarkuehl/kuhllib/wiki/STL-2.0" rel="nofollow">envision a system</a> of algorithms which can [optionally] take a property map (or actually sometimes multiple property maps) for each range. The idea is that <code>*it</code> yields a <em>key</em> (e.g., the <code>T&amp;</code> it currently do) which is then used with a property map which transforms the key into the actually accessed <em>value</em>. The transformation can, e.g., be the identity yielding the current behavior of the algorithms and a good default to be used when there is no property map. The example above would look something like this:</p> <pre><code>auto const cursor = c.begin(); std::printf("%c\n", c.map_source()(*cursor)); std::printf("%c\n", c.map_upper()(*cursor)); c.map_source()(*cursor, 'x'); std::copy(c.map_source(), c, std::ostreambuf_iterator&lt;char&gt;(std::cout)); std::copy(c.map_upper(), c, std::ostreambuf_iterator&lt;char&gt;(std::cout)); std::copy([](unsigned char c)-&gt;char{ return std::toupper(c); }, c, std::ostreambuf_iterator&lt;char&gt;(std::cout)); </code></pre> <p>The code assumes that the property maps yielding the source and the capitalized characters are obtained using <code>c.map_source()</code> and <code>c.map_upper()</code>, respectively. The last variant using <code>std::copy()</code> uses a lambda function as a property map.</p> <p>Sadly, I still haven't found the time to write up a coherent proposal to apply various improvements to the STL algorithms. ... nor do I have have an implementation putting it all together (I have a <a href="http://www.dietmar-kuehl.de/cxxrt/" rel="nofollow">somewhat clunky implementation</a> which is about 10 years old and doesn't benefit from various C++11 features which make it a lot easier; also, this implementation only concentrates on property maps and doesn't use the interface I currently envision).</p>
    singulars
    1. This table or related slice is empty.
    1. POHow does one implement a container which exposes multiple ranges?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USDietmar Kühl
    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
    1. COThe problem is that this forces one to discard the huge body of work that is existing algorithms expecting iterator pairs or ranges. It might be an interesting concept to apply eventually by the standards committee, but I wouldn't call this an idiomatic solution as of C++11/14 and their standard libraries.
      singulars
      1. PO
      1. USBilly ONeal
    2. CO@BillyONeal: I certainly agree with the assessment that it doesn't play nicely with the current algorithms. I'm discussing the various changes involved (the above code uses _ranges_ and _property maps_ with the Ranges SG) where the ideas are generally well received.
      singulars
      1. PO
      1. USDietmar Kühl
    3. COYeah, I'm not ripping on the ideas or anything like that; I'm just saying that doesn't answer the question *today* very well.
      singulars
      1. PO
      1. USBilly ONeal
 

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