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Identity Column Datatype

  • March 9, 2015 at 10:58 am

    #1782634

    Xavon (3/9/2015)

    RLilj33 (3/9/2015)

    This one threw me off. Can someone explain BOL (https://msdn.microsoft.com/en-us/library/ms189838.aspx):

    "data_type

    Is the data type of the identity column. Valid data types for an identity column are any data types of the integer data type category, except for the bit data type, or decimal data type."

    Thanks.

    That sentence is a little tough the parse, but think of it like:

    Valid data types for an identity column are (any data types of the integer data type category, except for the bit data type) or (decimal data type).

    That still does not include numeric, but gets it closer.

    I call it "Microsoft clarity." 😉

    Thanks for the question.

  • March 9, 2015 at 11:07 am

    #1782637

    Xavon (3/9/2015)

    RLilj33 (3/9/2015)

    This one threw me off. Can someone explain BOL (https://msdn.microsoft.com/en-us/library/ms189838.aspx):

    "data_type

    Is the data type of the identity column. Valid data types for an identity column are any data types of the integer data type category, except for the bit data type, or decimal data type."

    Thanks.

    That sentence is a little tough the parse, but think of it like:

    Valid data types for an identity column are (any data types of the integer data type category, except for the bit data type) or (decimal data type).

    That still does not include numeric, but gets it closer.

    Thanks for the clarification, Xavon

  • March 9, 2015 at 2:55 pm

    #1782709

    RLilj33 (3/9/2015)

    This one threw me off. Can someone explain BOL (https://msdn.microsoft.com/en-us/library/ms189838.aspx):

    "data_type

    Is the data type of the identity column. Valid data types for an identity column are any data types of the integer data type category, except for the bit data type, or decimal data type."

    Thanks.

    That statement in BOL is interpreted by some people as meaning one thing and by other people as meaning another. People who think that the commas represent pauses in speech that indicate meaning will parse it as "(integer types except bit) or decimal type". People who want to find an interpretation of "integer data type category" that exactly matches some well defined term used in the SQL definition have been known to claim that that phrase means "exact numeric types" so that it should be parsed as "integer types except (bit or decimal type)". Since "numeric data type" (as opposed to "exact numeric data type") is a synonym of "decimal data type" the first parsing delivers almost the correct meaning (to be completely correct it needs a constraint on the scale of the decimal type), while the second parsing delivers something that is horribly wrong.

    While there are plenty of errors in BOL, I suspect that here the small error (forgetting to mention the scale) is what this page has, not the big error (claiming that decimal [aka numeric] can never be used for identity columns).

    Tom

  • March 9, 2015 at 2:57 pm

    #1782710

    Well, if it were a conjunctional type of list there would be no comma, meaning both items were included in the exception. Not that English, grammar, etc, were exactly my strongest suits, but wasn't my weakest either, by any stretch.

  • March 10, 2015 at 7:27 am

    #1782902

    TomThomson (3/7/2015)

    This is a rather early repeat! We had an identical question on Jan 13th, less than 2 months ago; and then on Jan 20th we had another question for which the answer to this one was the first part of the explanation.

    So a nice easy question, and it will be rather disappointing if the correct answers end up much below 100%.

    I was not around for the earlier question, but still found this easy.

    Not only is the content easy, but even if you didn't know it would be easy to guess.

  • March 17, 2015 at 12:44 pm

    #1784577

    Nevyn (3/10/2015)

    TomThomson (3/7/2015)

    This is a rather early repeat! We had an identical question on Jan 13th, less than 2 months ago; and then on Jan 20th we had another question for which the answer to this one was the first part of the explanation.

    So a nice easy question, and it will be rather disappointing if the correct answers end up much below 100%.

    I was not around for the earlier question, but still found this easy.

    Not only is the content easy, but even if you didn't know it would be easy to guess.

    So it was repeated. Those who got it wrong the first time had another chance to get it right this time. Wonder how many got it wrong both times...

    Not all gray hairs are Dinosaurs!

  • March 17, 2015 at 8:01 pm

    #1784640

    Miles Neale (3/17/2015)

    Nevyn (3/10/2015)

    TomThomson (3/7/2015)

    This is a rather early repeat! We had an identical question on Jan 13th, less than 2 months ago; and then on Jan 20th we had another question for which the answer to this one was the first part of the explanation.

    So a nice easy question, and it will be rather disappointing if the correct answers end up much below 100%.

    I was not around for the earlier question, but still found this easy.

    Not only is the content easy, but even if you didn't know it would be easy to guess.

    So it was repeated. Those who got it wrong the first time had another chance to get it right this time. Wonder how many got it wrong both times...

    We've still got 41% getting it wrong this time round.

    Tom

  • March 18, 2015 at 9:39 am

    #1784813

    TomThomson (3/17/2015)

    Miles Neale (3/17/2015)

    Nevyn (3/10/2015)

    TomThomson (3/7/2015)

    This is a rather early repeat! We had an identical question on Jan 13th, less than 2 months ago; and then on Jan 20th we had another question for which the answer to this one was the first part of the explanation.

    So a nice easy question, and it will be rather disappointing if the correct answers end up much below 100%.

    I was not around for the earlier question, but still found this easy.

    Not only is the content easy, but even if you didn't know it would be easy to guess.

    So it was repeated. Those who got it wrong the first time had another chance to get it right this time. Wonder how many got it wrong both times...

    We've still got 41% getting it wrong this time round.

    If we run it again in two or three months do you think that will go up or down?

    Not all gray hairs are Dinosaurs!

  • March 18, 2015 at 8:33 pm

    #1784964

    Miles Neale (3/18/2015)

    TomThomson (3/17/2015)

    Miles Neale (3/17/2015)

    Nevyn (3/10/2015)

    TomThomson (3/7/2015)

    This is a rather early repeat! We had an identical question on Jan 13th, less than 2 months ago; and then on Jan 20th we had another question for which the answer to this one was the first part of the explanation.

    So a nice easy question, and it will be rather disappointing if the correct answers end up much below 100%.

    I was not around for the earlier question, but still found this easy.

    Not only is the content easy, but even if you didn't know it would be easy to guess.

    So it was repeated. Those who got it wrong the first time had another chance to get it right this time. Wonder how many got it wrong both times...

    We've still got 41% getting it wrong this time round.

    If we run it again in two or three months do you think that will go up or down?

    Oh.please don't ask that question - I'm scared that the correct answer may be the wrong one. If something this simple can't be taught ...

    On of the reasons I look at QotD is that I think people will learn from it. Otherwise the questions I generate (and those of my comments which I believe will help people understand SQL) are pretty worthless. I want to believe that qotD and comments on it are useful.

    Tom

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