>I know that it is good practice not to use data as keys.
>Would one think of a smalldatetime as data ?

"Mikael" <Mikael@discussions.microsoft.com> wrote in message
news:C87DFC32-7FC0-42EA-84A9-46268EF539C2@microsoft.com...
>I know that it is good practice not to use data as keys.
> Would one think of a smalldatetime as data ?
>
> My situation is that i collect historical information on financial
> instruments.
> I have a price table with a composit primary key of instumentId and
> smalldatetime(but no time). Besides the key, I have a value for the
> instrument.
>
> I think it is ok to use the smalldatetime, but my collegue dissagrees and
> I
> yould like a second opinion.
>
>
> --
> Best regards
>
> Mikael

"Mikael" <Mikael@discussions.microsoft.com> wrote in message
news:1A438DD4-C93C-4F86-BB00-844B682EF44D@microsoft.com...
> Yes:
> CREATE TABLE price
> (
> [InstrId] int not null,
> [Stamp] smalldatetime not null,
> [Price] decimal(28,10) not null,
> primary key ([InstrId],[Stamp])
> )
>
>
> [InstrId] is a forign key to another table that contains the instruments
> characteristics.
>
> --
> Best regards
>
> Mikael
>
>
> "Uri Dimant" wrote:
>
>> Mikael
>> >I know that it is good practice not to use data as keys.
>> >Would one think of a smalldatetime as data ?
>>
>> What did you mean? Can you show us your table's structure?
>>
>>
>>
>> "Mikael" <Mikael@discussions.microsoft.com> wrote in message
>> news:C87DFC32-7FC0-42EA-84A9-46268EF539C2@microsoft.com...
>> >I know that it is good practice not to use data as keys.
>> > Would one think of a smalldatetime as data ?
>> >
>> > My situation is that i collect historical information on financial
>> > instruments.
>> > I have a price table with a composit primary key of instumentId and
>> > smalldatetime(but no time). Besides the key, I have a value for the
>> > instrument.
>> >
>> > I think it is ok to use the smalldatetime, but my collegue dissagrees
>> > and
>> > I
>> > yould like a second opinion.
>> >
>> >
>> > --
>> > Best regards
>> >
>> > Mikael
>>
>>
>>

"Mikael" <Mikael@discussions.microsoft.com> wrote in message
news:C87DFC32-7FC0-42EA-84A9-46268EF539C2@microsoft.com...
>I know that it is good practice not to use data as keys.

> Would one think of a smalldatetime as data ?
>
> My situation is that i collect historical information on financial
> instruments.
> I have a price table with a composit primary key of instumentId and
> smalldatetime(but no time). Besides the key, I have a value for the
> instrument.
>
> I think it is ok to use the smalldatetime, but my collegue dissagrees and
> I
> yould like a second opinion.

"Uri Dimant" <urid@iscar.co.il> wrote in message
news:%23fipG1lTGHA.2244@TK2MSFTNGP14.phx.gbl...
> Mikael
> http://www.sql-server-performance.com/composite_indexes.asp

\"David Portas" <REMOVE_BEFORE_REPLYING_dportas@acm.org> wrote in message
news:%23xLFDBmTGHA.1236@TK2MSFTNGP11.phx.gbl...
> "Uri Dimant" <urid@iscar.co.il> wrote in message
> news:%23fipG1lTGHA.2244@TK2MSFTNGP14.phx.gbl...
>> Mikael
>> http://www.sql-server-performance.com/composite_indexes.asp
>
> From that page:
> "A composite index is an index that is made up of more than one column. In
> some cases, a composite index is also a covering index. See this URL for
> information on covering indexes. Generally speaking, composite indexes
> (with the exception of covering indexes) should be avoided. This is
> because composite indexes tend to be wide, which means that the index will
> be larger, requiring more disk I/O to read it, hurting performance."
>
> This is plain bad advice. A non-covering composite index is very useful if
> a sargable query matches the indexed columns for example. That last
> sentence is no argument at all. The index is as large as the data - no
> more and no less.
>
> --
> David Portas, SQL Server MVP
>
> Whenever possible please post enough code to reproduce your problem.
> Including CREATE TABLE and INSERT statements usually helps.
> State what version of SQL Server you are using and specify the content
> of any error messages.
>
> SQL Server Books Online:
> http://msdn2.microsoft.com/library/ms130214(en-US,SQL.90).aspx
> --
>
>

"Uri Dimant" wrote:

> Mikael
> >I know that it is good practice not to use data as keys.
> >Would one think of a smalldatetime as data ?
>
> What did you mean? Can you show us your table's structure?
>
>
>
> "Mikael" <Mikael@discussions.microsoft.com> wrote in message
> news:C87DFC32-7FC0-42EA-84A9-46268EF539C2@microsoft.com...
> >I know that it is good practice not to use data as keys.
> > Would one think of a smalldatetime as data ?
> >
> > My situation is that i collect historical information on financial
> > instruments.
> > I have a price table with a composit primary key of instumentId and
> > smalldatetime(but no time). Besides the key, I have a value for the
> > instrument.
> >
> > I think it is ok to use the smalldatetime, but my collegue dissagrees and
> > I
> > yould like a second opinion.
> >
> >
> > --
> > Best regards
> >
> > Mikael
>
>