BIT320 Remix — Troubleshooting

December 19, 2005

Helpful Hint

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Requirement #6 asks us to generate a “show all tables and columns” report.  At first we weren’t quite sure what this meant.  After some exploration, we discovered the list_column_info_for_all.sql in our SQL directories.  This should pull together all the tables and views.

Hope this helps!

In Kevin's Blog, 12/19/2005 | Original | Archive | Post to del.icio.us | Technorati

Update Forms

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In class we’ve mainly been focusing on how to add new data via forms — but what about updating data?  What if the sales representative enters the wrong information?   Or what if one of the stores changes phone numbers?  The trick is to use the update command instead of the insert command.  You also need to use the attribute axis (@) in place of the bind parameter.  You should end up with something looking like this:

xsql:set-page-param name=”id1″ value=”{@id1}”

UPDATE tableName SET id1 = ‘{@id1}’
WHERE id2 = ‘{@id2}’;

Hopefully this helps the other teams out.  Good luck with the projects!

In Kevin's Blog, 12/19/2005 | Original | Archive | Post to del.icio.us | Technorati

RSS - Team Goes for Bonus

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Matt and I have been working on the RSS feed all night and we think we finally got it working!  The feed is located at the following URL: http://elab-linux4.bus.umich.edu:8080/%7Ekevlers/RSS/testRSS.xsql (Bud - can you tell us if we’re all set with the feed)

The purpose of the feed is to notify customers of new store additions to the database.  This is especially important to customers who do not have any stores in their immediate area.  They can use the feed as a watch-list to see if any stores start carrying Denali Flavors.  The xsql file pulls the information directly from the database, so it should be a valid feed, as opposed to just a well-formed document.

If any other teams are attempting to get the RSS feed working, I would recommend looking at this web site.

In Kevin's Blog, 12/19/2005 | Original | Archive | Post to del.icio.us | Technorati

December 11, 2005

Frame Alternatives

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As Bud already touched on, frames are generally looked down upon in the web design community.  In fact, some go so far as to say that using frames is one of the top ten biggest mistakes in web design.  A brief search on the term frames on Google revealed many web sites, such as this one, that discuss the downsides of using frames.

Many of you are probably wondering how to include a navigational structure on top of the XSLT pages if you can’t use frames.

  1. One option is to include an inline frame.  Inline frames are similar to frames pages except that the inline frame and its contents are embedded on an existing Web page, so you don’t need a separate frames page.  Below is an example:


     
  1. Another way to include content is to use server side include.  SSI
     allows you add dynamically generate content into an existing HTML page, with
     the following code <!–#include virtual="PageToIncludeHere.htm" –>

    2.  
  2. Another option is to simply include the navigational structure directly
     in the XSLT pages.  However, this becomes complicated when updating.

In Kevin's Blog, 12/11/2005 | Original | Archive | Post to del.icio.us | Technorati

December 8, 2005

Error Codes and what they mean

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Programming can be difficult, especially when errors occur.  Luckily, when they do happen, XSLT produces a number of different error codes to help troubleshoot the issue.  The error codes produced by Shady Waters’ code helped me determine what the cause of the problem is.

The first error code, ORA-06550, gives the line and column location of the SQL block where there was an error.

The second error code, ORA-00947, was a little more helpful.  This code occurs when an SQL statement requires two sets of values equal in number, and the second set has fewer values than the first set.

By typing these error codes into Google (or if you want to make me happy: search.msn.com), you can see the cause as well as the solution.

In Kevin's Blog, 12/08/2005 | Original | Archive | Post to del.icio.us | Technorati

Re: JB’s problems in her ice cream cone

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Shady Waters recently posted about a problem they are having with project 2.  The error message seems to indicate that there aren’t enough input values.  Does your table contain more than just those three fields?  If the table contains more than three fields and it’s set to not allow null values, then this error would occur.  Check the number of items in each set and change the SQL statement to make them equal.

In Kevin's Blog, 12/08/2005 | Original | Archive | Post to del.icio.us | Technorati

December 7, 2005

XSQL1 Error

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Debugging code is oftentimes a very daunting task.  To prevent others from encountering the same error I did, I wanted to point out a mistake on page 14 of the XSQL1 guide.  According to the slide, the where portion of the select statement is entered incorrectly as where age = ?

As it turns out, this should actually be entered as where age=?

So what’s the difference?  In the first instance of where, there is a whitespace in front of the question mark.  If the default value for age is 32, the system will search for ” 32″, as opposed to the desired value of “32″.  With the extra space, the query will return no matches.

In Kevin's Blog, 12/07/2005 | Original | Archive | Post to del.icio.us | Technorati

December 6, 2005

Wireless and BIT320

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Kevin reported today that wireless was not working for him when accessing XSQL pages on elab-linux4. Not the case here. If I go to this URL under wireless:

http://elab-linux4.bus.umich.edu:8080/~fpgstu4

I get my webapps directory. One thing that might be happening is some sort of load management when the wireless capacity in the library becomes saturated. When you cannot access elab-linux4, are you able to get other web pages (ones that have not been cached on your hard drive)?

In Blogonautic Solutions, 12/06/2005 | Original | Archive | Post to del.icio.us | Technorati

December 1, 2005

Inserting code: now easier than ever!

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I just discovered an even easier way of displaying code on the community engine site.  Instead the laborious process of inserting the character codes for the opening and closing brackets or taking screenshots, you can just insert all the code into an HTML textbox, as shown below: 
guaranteed to display correctly.  To do this, I
 would recommend inserting a textbox in Microsoft FrontPage and then pasting
 your code into the textbox.  Then copy and paste all the HTML from
 FrontPage to Wordpress.

In Kevin's Blog, 12/01/2005 | Original | Archive | Post to del.icio.us | Technorati

November 13, 2005

Wordpress and special characters

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Kevin has written a great post on Wordpress, explaining how to get < and > to show up. We had some problems with the post because Kevin appears to have written it in Word, causing some non-standard-compliant codes to be inserted that broke the processing chain.

Some would say this is evidence of Microsoft purposely messing things up to break open standards. Personally, I think Microsoft just does not bend over backwards to support open standards, like many other vendors, even open source ones. At the end of the day, you have to accept that there will be some breakage and work around it as it arises.

In Blogonautic Solutions, 11/13/2005 | Original | Archive | Post to del.icio.us | Technorati

Wordpress and Character Codes

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As observed by Matt, Wordpress has the tendency of treating anything in brackets (<>) as code, which can sometimes cause a problem when you want others to review your code. Matt suggested placing a space between the angle brackets and the content of the brackets. A better way to do this is to use the character code. I listed the codes and the corresponding symbols below:

< is &lt; (That's ampersand and lt;)

> is &gt; (That's ampersand and gt;)

By using these codes in place of the brackets, your posts now should display properly.

In Kevin's Blog, 11/13/2005 | Original | Archive | Post to del.icio.us | Technorati

October 18, 2005

Data Types

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When creating a table in Oracle that contains more than one column as the primary key, where do we specify the data type of the key?  In the premiere database order_line table, the combination of order_num and part_num create the primary key.  When creating this table, we did not specify a data type.  However, when I run the command “describe order_line” Oracle appears to have assigned a data type.  Is this because the table is an associative entity and Oracle can, as a result, determine the data type?

In Kevin's Blog, 10/18/2005 | Original | Archive | Post to del.icio.us | Technorati

October 3, 2005

Blog problems

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Supriya notes several issues with her blog:

First, it won’t let me publish my blogs and give me errors regarding the headers. Aga also complained having the same problem a few days back. Surprisingly, the blog still posts in spite of the error.

Now, as I am trying to create links— instead of making my text a hyperlink, it just inserts the actual link

On the first issue, we have noted this in the past. It’s just a bug. On the second, I’m not sure what is going on. Have you tried closing and restarting your browser? Are you using firefox?

We have an opportunity to use a more advanced version of the wordpress platform, though still experimental. It is a bit less buggy than this one. Send me a mail if you want to use it.

In Blogonautic Solutions, 10/03/2005 | Original | Archive | Post to del.icio.us | Technorati

September 24, 2005

Making WordPress Categories Stick

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Matt makes a great post which I will just recopy here:

There is one problem wordpress that was frustrating for me when I first started blogging. Whenever I create a new category for my blog it does not work the first time I publish it. An example of this was my last blog. If you’ll notice I categorized it with under technology, Google, and Microsoft. In this instance Google and Microsoft were new categorizes. The problem occurs when I publish it. What happens is that the new categorizes does not register with the blog. In order to fix this problem I have to click edit and re-select the categories. This problem is easy remedy but still annoying.

Another solution is to hit “Save and Continue Editing”. You will still have to go back and reclick your category, but you will save the step of having to publish and then return to the writing interface.

In Blogonautic Solutions, 09/24/2005 | Original | Archive | Post to del.icio.us | Technorati

September 16, 2005

The Wonderful World of Alpha Software Do Not Use

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Supriya is the latest of many (for instance Super Matt, Matt’s Musings, and Kevin’s Blog) to note the alpha (do not use) nature of our blogging software. Specifically, she has experienced this error message:

Warning: Cannot modify header information - headers already sent by (output started at /home/highoct/public_html/wp-inst/wp-includes/comment-functions.php:516) in /home/highoct/public_html/wp-inst/wp-admin/post.php on line 110

Essentially, nothing bad has happened. Your post posted. This is just the unfinished nature of the software. Personally, I feel this was one of my more difficult decisions of the term. I decided to live with a little unfinished flavor to make the remix engine work.

In Blogonautic Solutions, 09/16/2005 | Original | Archive | Post to del.icio.us | Technorati

September 11, 2005

Duplicate entries

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As Kevin rightly observes:

When editing either a blog post or del.cio.us bookmark, the remix site seems to pick up a new copy of the post rather than modifying the existing one.

Right now, there seems no way around it, but I will research it. It has to do with when a feed item is considered new and how you identify a feed item. There are some standards for this, but they are followed unevenly. There is even some debate as to whether items are, in fact, updateable. For now, just treat everything you write and publish as though it were sent, much like email.

In Blogonautic Solutions, 09/11/2005 | Original | Archive | Post to del.icio.us | Technorati

Duplicate posts

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When editing either a blog post or del.cio.us bookmark, the remix site seems to pick up a new copy of the post rather than modifying the existing one.  This causes duplicate entries to appear.  Is there a way around this?  Thanks.

In Kevin's Blog, 09/11/2005 | Original | Archive | Post to del.icio.us | Technorati