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All the Perl that's Practical to Extract and Report

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  • I wonder if mapping objects to records is working in this case. This is just brainstorming, so ignore me if lighting doesn't strike.

    One random thought is that you could have something that maps bits of SQL and objects that contain these bits of SQL, turning them into full-blown queries only when it's necessary to pull a row. For example, you'd set constraints such as associated with this person's name and matches the previous constraint's office_id field, passing that to a method that builds the appro

    • Can you give an example? It seems that having objects that contain bits of SQL and then trying to put all of that together is a daunting task. My underlying structure seems sound and it has worked wonderfully. All I do (mostly) is subclass a PersistentObject class, provide some class data and I have 20 to 30 methods instantly built for only about 5 minutes of work. Previously, I was trying to do all of that by hand for each "thing" in the database and it was an absolute nightmare. This is much faster,

      • Sounds like you've partially rewritten Class::DBI and/or Alzabo, both of which are designed to let you represent database rows as objects (Alzabo also does some other neat things too).

        • Alzabo doesn't support MS SQL Server, which is what I am running on. I had checked out some of the Perl OO Persistence work, but most of it had one or more of the following limitations:

          • Doesn't support MS SQL Server
          • Doesn't support an existing schema
          • Poor documentation
          • No longer maintained

          Tangram [soundobjectlogic.com] looked interesting, but from what I could tell, gradual refactoring wasn't an option as it appears to go from the object to the schema. Existing schemas meant I was out of luck.

          I'm going to grab Alzabo and Class::DBI and see if I can work with them. One problem with Class::DBI is the the get_ and set_ methods, by default, use the field names in the database. I think the programmer should be forced to decouple that when creating the object. Otherwise, if you need to change a field name, you have to find every method that touches that field and change its name. There are methods to change the names of the accessors and mutators, but they have to be explicitly used. If you forget about them, whoops!

          • Of the four problems you cite, Class::DBI doesn't have any of them, and Alzabo just doesn't support MS SQL server. Adding support for it wouldn't be too hard, however.

            I disagree about decoupling mtehod names from column names, however. If it changes in the schema, that probably means that the _meaning_ has changed, so why not change the method name?

            • It might change the meaning, but it also might be a relatively trivial change that shouldn't affect the overall design of things. For example, with my code, the programmer must explicitly provide class data that maps external names (used in methods), to field names in the database. Here's a map for our "local regions" (note that the field names are not aligned because of difficulties formatting one use.perl). I want <pre> tags :)

              my %map = ( qw/
                id localRegionID
                global_reg

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