Re: [uug] regexp advice

[QuickBrownFox]

Thanks.  I appreciate the suggestions.  Unfortunately, I can't store the 
metadata in a separate data field.  I wish I could, but the application 
requires that the data elements be very atomic.  You see, this is for an 
inventory tracking application for my work, and the databases are 
designed to be very extendable and adaptable to the specific needs of 
the individual departments.  There are several, I guess you could call 
them 'abstracted' types (ie. short text, long text, url, file, 
single-select list, multiple-select list, etc) and each of the data 
elements in the inventory has one of these types associated with it.  
Each of those types is associated (in another table) with a MySQL type.  
This way, we can build the scripting so that the database administrators 
can add or delete fields easily, and the different abstracted types can 
be treated differently in the scripting.  For example, both a url and a 
short text could be stored as a varchar, but the way the script presents 
a short text in the web interface is with a simple text box, while a url 
is presented with a link, and a text box.  This is of course a simple 
example, but illustrates the idea.

Anyway, the short answer is that every abstract type needs to be 
associated with only one MySQL type, and the stored file still needs to 
include the filename, and, if available the mime type.

So, just 'cause I'm curious, is there a performance advantage to using 
the regexp to remove the metadata header, rather than just extracting 
the data by using the regexp backreference?  I suppose, since a 'file' 
is being stored as a mediumblob (max about 16 MB) that it could be a lot 
of data to run through the regexp engine.  Hmm.  I'll have to think 
about that.

Thanks again,
Lloyd
Mac Newbold wrote:
Today at 4:12pm, Lloyd T Brown said:
 

Here's the situation.  I'm encoding files (base 64 encoding) to put them
into a database.  I want to also include some metadata with the encoded
string, namely filename and mime type.  Here's an example of the format
I decided to use.
"filename: somefilename.txt;mime-type: text/plain; data:
VGhpcyBpcyBhbiBlbmNvZGVkIHN0cmluZw=="
   

I know you're really asking for a regexp, but if I may, I'd like to
suggest you [re]consider having the meta data be stored as a separate
column in the table. This could have several benefits:
1) Don't have to parse it out of a blob/text field
2) Can use the meta data for db queries (i.e. selecting by name/type, etc.)
3) Simpler code to read and write file entries in the database
4) More flexible: much easier to expand your meta-data set later
5) That's what databases are for
But of course I don't know the entire situation, so this may not be
appropriate in your setting.
BTW, the regexp looked pretty good, and I pretty much agree with what
Jacob Fugal said.
Thanks,
Mac
--
Mac Newbold             MNE - Mac Newbold Enterprises, LLC
[EMAIL PROTECTED]       http://www.macnewbold.com/
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