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RE: Stairway to Data, Step 1: The Basics

harij73 — Fri, 27 Jul 2012 10:22:07 GMT

Nice one, bit vague for the people who cannot understand Mathematics or terms related to mathematics. A great effort by Joe in putting down the basics into work. Nice

RE: Stairway to Data, Step 1: The Basics

rmechaber — Fri, 29 Jul 2011 15:38:59 GMT

[quote][b]bagofbirds-767347 (7/28/2011)[/b][hr][quote][b]Thomas Krystofiak (5/12/2011)[/b][hr]I am pretty sure T.S. Eliot never write the lines you attributed to him. Got a reference by chance?[/quote]um, google it. should find about a thousand references.[/quote]Done and marked: see my reply to this thread at [url=http://www.sqlservercentral.com/Forums/FindPost1107717.aspx]http://www.sqlservercentral.com/Forums/FindPost1107717.aspx[/url]Rich

RE: Stairway to Data, Step 1: The Basics

bagofbirds-767347 — Thu, 28 Jul 2011 10:08:07 GMT

[quote][b]Thomas Krystofiak (5/12/2011)[/b][hr]I am pretty sure T.S. Eliot never write the lines you attributed to him. Got a reference by chance?[/quote]um, google it. should find about a thousand references.

RE: Stairway to Data, Step 1: The Basics

Allen Nugent — Wed, 01 Jun 2011 00:01:47 GMT

Great article, but I'm worried about two of the defnitions. In science and engineering, 'precision' is what you called 'granularity'. A more precise instrument is one that allows smaller features to be resolved. Repeatability is just called 'repeatability', and its relationship with precision is not obvious (e.g. a worn micrometer could still give readings to 0.001 mm or 0.0001 inch, but they might be different every time).Looking forward to the series!-- Al

RE: Stairway to Data, Step 1: The Basics

rmechaber — Fri, 13 May 2011 17:48:29 GMT

[quote][b]Aleph_0 (5/13/2011)[/b][hr]Hi, I'm new to SQL (just dove in a couple of months ago with no programming background) and would absolutely love to be able to win the copy of SQL for Smarties mentioned in the article. I've read through a couple of beginner books and now I'm currently reading a borrowed copy of the 2nd edition.I've done my homework! Do I need to email it somewhere or just post it here? Thanks.[/quote]Welcome to SQL Server Central! This is a fantastic community of information.May I suggest that you focus not only on writing efficient T-SQL, but that you work on understanding what makes good database design, how to normalize tables, etc. If you build a solid schema/table structure that accurately reflects your business, you will easily be able to make later changes to enhance efficiency (indexes come to mind). OTOH, if you build a poor foundation with repeating groups in table columns (for example), it will be much harder to undo that later. I find that part of this design process is imagination, both positive (what if the company expands into new product lines or geographic areas?) and negative (what if this person is fired? can their accounts be transferred easily without breaking relationships?). Good luck!Rich

RE: Stairway to Data, Step 1: The Basics

Jasmine D. Adamson — Fri, 13 May 2011 17:05:40 GMT

[quote][b]Aleph_0 (5/13/2011)[/b][hr](just dove in a couple of months ago with no programming background)[/quote]IMO, that is the best place to start from. Too many programmers approach SQL with a "it's not my real job just something I have to poke around in sometimes" attitude, and we get a lot of poor DB design from that. You're starting with the right literature too - Joe's stuff is great! When I went to college, we were taught EF Codd relations straight up - we didn't even use any software till the second half of the class. If more people started off that way, instead of by hacking together something Visual Studio built for them, then more applications would be built on solid foundations and everybody would save time and money.The DB is the foundation of your application. Everything else is built on top of that. If more developers approached it that way, it would be a good thing. So keep doing what you're doing - you'll be a valuable asset because of it. Now, if we could just get hiring managers to understand all that crap I just said... :)

RE: Stairway to Data, Step 1: The Basics

Aleph_0 — Fri, 13 May 2011 14:51:52 GMT

Hi, I'm new to SQL (just dove in a couple of months ago with no programming background) and would absolutely love to be able to win the copy of SQL for Smarties mentioned in the article. I've read through a couple of beginner books and now I'm currently reading a borrowed copy of the 2nd edition.I've done my homework! Do I need to email it somewhere or just post it here? Thanks.

RE: Stairway to Data, Step 1: The Basics

CELKO — Thu, 12 May 2011 13:41:15 GMT

I love those Manga Guides! there a poster of the basic SI units and the compound units that can be formed from them. Thus we get kilometers per hour for speed, the Newton for force; it is equal to the amount of net force required to accelerate a mass of one kilogram at a rate of one meter per second squared, etc.

RE: Stairway to Data, Step 1: The Basics

Thomas Krystofiak — Thu, 12 May 2011 09:52:49 GMT

I am pretty sure T.S. Eliot never write the lines you attributed to him. Got a reference by chance?

RE: Stairway to Data, Step 1: The Basics

RichB — Thu, 12 May 2011 08:53:10 GMT

[quote][b]Mark Dalley (5/12/2011)[/b][hr]Now, if every column of numeric data on the various DBMSs carried the units around with it (dollars, years, days etc) so that sanity checks of this kind could be performed automatically when queries were created, I wonder how many calculations would get thrown out as total nonsense?[/quote]Now that would be a feature.

RE: Stairway to Data, Step 1: The Basics

rmechaber — Thu, 12 May 2011 07:58:39 GMT

Nice article, Joe, but I'm a bit dismayed that a putatively authoritative piece on data integrity, organization, and relationships began with a mis-quoted excerpt of T.S. Eliot's poem.The quote I find reads:[quote]Where is the wisdom we have lost in knowledge?Where is the knowledge we have lost in information?[/quote](Source: [url=http://www.tech-samaritan.org/blog/2010/06/16/choruses-from-the-rock-t-s-eliot/]http://www.tech-samaritan.org/blog/2010/06/16/choruses-from-the-rock-t-s-eliot/[/url]I don't mind you paraphrasing, but please indicate that you have done so. Thanks,Rich

RE: Stairway to Data, Step 1: The Basics

Mark Dalley — Thu, 12 May 2011 07:13:37 GMT

That's right - units cancel when you are dividing, if they are the same. You can't divide a number of eggs by a number of eggs and get a number of eggs. What you get is a pure number (eg. a number of times more fertile chicken A is compared to chicken B, going by the number of eggs laid).You can divide a number of meters by a number of seconds and get a number of meters per second - a different thing, but quite sensible.What you can *never* do is add or subtract meters to seconds - or any items which are in different units - and get anything meaningful.Now, if every column of numeric data on the various DBMSs carried the units around with it (dollars, years, days etc) so that sanity checks of this kind could be performed automatically when queries were created, I wonder how many calculations would get thrown out as total nonsense?

RE: Stairway to Data, Step 1: The Basics

ross.cecil — Thu, 12 May 2011 07:00:30 GMT

Great article - its nice to see someone approaching an understanding of the data that underlies the database!The discussion about scales that are both nonlinear and directional reminded me of some work I did years ago in economic geography work. Geography is the study of spatial distributions and we were trying to determine from aerial photographs of rural U.S. places where the residents shopped (i.e., which town the farmer/rancher was likely to visit). In the course of our work we came across some earlier research that had used a gravity-model to determine this - the researchers used an inverse square calculation based on the population (instead of mass) and distance to determine the relative attractiveness of a place. Our photo-interpretation work confirmed the model. All we had to do was look at the wear patterns at rural intersections to determine the place to which the residents most frequently traveled. Since then I've been able to use similar models to derived other information from data such as the likelihood of two events being related based on their amplitude/area/concentration and distance apart (on whatever scale makes sense).

RE: Stairway to Data, Step 1: The Basics

Thomas Abraham — Thu, 12 May 2011 06:57:05 GMT

[quote][b]RichB (5/12/2011)[/b][hr]No problem with every dollar being owned by 4 people.It's how the fed works, is it not?[/quote]Having worked for the Fed, I took umbrage with that remark - after I finished laughing, of course.Interesting that you said "every dollar owned by 4 people", as I don't believe that "people" was the specified unit of measure in "12/$3". We use phrases like "4 for a $" all the time, but it only makes sense if the missing unit of measurement can be inferred from the context. E.g. Apples, Feet, Left Nostril Inhalers, etc.Before I get too far afield, kudos to Joe for an interesting piece. Always good to get something related to databases that isn't just syntax, of config settings, or how to trick SQL Server into doing your bidding.

RE: Stairway to Data, Step 1: The Basics

RichB — Thu, 12 May 2011 06:45:44 GMT

No problem with every dollar being owned by 4 people.It's how the fed works, is it not?

RE: Stairway to Data, Step 1: The Basics

Thomas Abraham — Thu, 12 May 2011 06:32:44 GMT

[quote][b]Phil Factor (5/12/2011)[/b][hr][quote]Reminded me a lot of a couple of books I use to explain to my wife what I do: The Manga Guides to Statistics and Databases[/quote]You can't divide twelve eggs by three eggs can you?[/quote]Don't units of measurement cancel out? 4 feet/2 feet can also be interpreted as "how many times does "2 feet" go into "4 feet" -> 2 times. So, wouldn't 12 eggs/3eggs just equal 4? But, 12/$3 doesn't make sense to me. However, 12 feet/$3 does. (I can, for example, grok "4 feet for a dollar".)

RE: Stairway to Data, Step 1: The Basics

Phil Factor — Thu, 12 May 2011 04:16:35 GMT

[quote]Reminded me a lot of a couple of books I use to explain to my wife what I do: The Manga Guides to Statistics and Databases[/quote]Ah, the Manga Guide! We all read it; it is good. Well done Joe, it is a great article which I really enjoyed. So many of the subtler problems I have to fix in applications boil down to this sort of problem. There is one chestnut that has always puzzled me. MONEY, like DATETIME, is a quantifier. A MONEY datatype tells you only the amount of money. I'm not a mathematician, but how can division or multiplication be done with a MONEY value as the right-hand value (rvalue)? Surely this is a programming error? You can't divide twelve eggs by three eggs can you?

RE: Stairway to Data, Step 1: The Basics

RichB — Thu, 12 May 2011 03:55:43 GMT

Nice read, puts a lot of good points together very coherently.Reminded me a lot of a couple of books I use to explain to my wife what I do: The Manga Guides to Statistics and Databases.

RE: Stairway to Data, Step 1: The Basics

Anipaul — Thu, 12 May 2011 01:00:38 GMT

Nice discussion on the basics...Where is the information? Lost in the data. Where is the data? Lost in the #@%&! database! -- Joe Celko --:w00t::-D

Stairway to Data, Step 1: The Basics

CELKO — Wed, 11 May 2011 22:45:01 GMT

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