The Object

One of the difficult things about object-oriented programming for a non-object-oriented programmer is the whole object thing. What is an object? I knew a little just from having looked at this kind of stuff, but I didn't really know what was going on. This was to be my first foray from procedural programming into OO. I knew if I misstepped, it could be deadly (well, not really, but at least not very fun).

My first trick was to pass object within PowerShell, rather than writing to a text file and reading that text file. Reducing disk I/O's would improve the speed of the script and decrease the number of errors if I were to, say, run four scripts at the same time. This is pretty easily accomplished using an array of strings for DQL commands:

$DQLStatement = @()

$DQLStatement += "select * from dm_user"

$DQLStatement += "go"

$DQLStatement idql32.exe

That doesn't use any disk I/O (except for loading idql32.exe from the disk, which I haven't learned to get around yet). But it doesn't get us any closer to the ideal of using objects from Documentum, which is one of the advantages of Documentum in the first place. So, I wrote what I consider to be one of my crowning achievements at the company: Get-DocumentumObject.ps1. This script returns the result from idql32.exe, looks at the headers and lengths, and returns an object based on what it receives. It is much more elegant than what I was doing before. The first one I wrote returned the data to an XML file, but now it returns it as an object right in PowerShell, using the custom PSObject type. I will post it in a later post.

One of the main advantages of this is it only requires one line of code to return a Documentum object from a select statement:
$DctmObject = "select * from dm_user" y:\scripts\Get-DocumentumObject.ps1
At this point, $DctmObject would be a PowerShell object with all the information from the select statement.

A caveat here about this method: it is not perfect at all. If the return from the select statement is wider than a certain length, for some reason PowerShell wraps the text to the next line, causing the object to break. I may someday find a fix for this, but most of the time I don't need to use 40 columns, just a few.