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| Non-WTF Job: C++ Developer at Good Grievance (Ronkonkoma, NY) |
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| Non-WTF Job: C++ Developer at Good Grievance (Ronkonkoma, NY) |
| « Jurassic Programmers | 1.13: Bad News » |
"It should be pretty simple," David M naïvely stated, "just look in the Agent_ProductLines table, right?"
"Uhhh," David's coworker, James, replied in a slightly condescending tone, "no." David was starting to get used to such responses. Nothing in his new job was "pretty simple" to simple to do.
"Okaaay... so how exactly can we tell if a particular Agent is allowed to a given Product Line"
James groaned. "Well as you know, the original database developer, wasn't really a fan of normalization, the relational model, or just plain simple common sense. In this case, he did not want to 'waste space' by creating a table just to store the Agent-Product Line relation."
David sighed. He knew exactly what was coming up: some stupid comma, tilde, asterisk delimited string on the Agency table.
"Oh it gets worse," James replied, "see, take a look at this column, the NVARCHAR(2000) one called strProductLines?"
David took a look. He was confronted with something far worse than a delimited string...
012-3100000100110000001000000103000001001100000-1011010101---0010011000000100000001000001001---00000500000010600010011000000100000001000001001100000010
"What the--"
"Here," James said, cutting him off, "let me show you how it works." He grabbed a pen and a pad of paper, and started to draw a little table ...
ID 1 2 3 4 5 6 7 8 ... Value 0 1 1 - 3 1 0 0 ...
"Wait," David said, "you're telling me, the index of each character corresponds to the product line? And a one means that they can sell a product line?"
"Yes," James replied, "but it's a bit more than that. '0' means they can't sell, '1' means they can, '-' means there is no such product with that ID, and '2', '3', '4' - all through '9', all mean different things. Like, '3' means that the agent has received training on the product line, but has not been approved to sell, and so on."
David buried his face in his hands for a brief moment. "So how exactly can can I build this 'Find Agency by Product Line' feature?"
"Well," James winked, "it should be pretty simple."
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When I showed this article to my colleague he said this looked elegant and nice.
He also likes to concatenate the foreign keys in one field (comma delimited). This is what I had to write to connect two tables whose only connection were comma delimited foreign keys:
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Wrong. It's terrible. It's worse than terrible. The fact that you even suggest it tells me to stay far away from anything you've worked on, or for that matter anything that anyone who ever associated with you worked on.
More evidence that everyone should stay far away from your code. The SUBSTRING() solution is one of the worst possible ones. It not only completely removes the advantage of indexes (unless you happen to be searching for the first character of the column values), but it requires the massive overhead of a function call for *every single row* in the table. Only some kind of total imbecile would even suggest this as a possible solution; it would take a total moron to even think that this is "Not that bad.". Please, for the sake of all that's good in the world, find yourself a new line of work far removed from computers. In fact, I'm not even sure you should be allowed near a computer, as a matter of public safety. |
| « Jurassic Programmers | 1.13: Bad News » |
emil:
