DateTime fields, methods over such fields, DateTime depended SQL where-clause and SQL-functions.

[Ruslan Zasukhin]

On 12/9/04 2:15 AM, "Ivan Smahin" <IvanSmahin at public.kherson.ua> wrote:

> Hello All,
> 
>      This is short info about usage of DateTime features in Valentina 2.
> 
>      1. There are three datetime types in Valentina 2:
>         Date, Time and DateTime.
> 
>         As far as I know, storing milliseconds in time and datetime fields
>         is new to version 1.
> 
>         Important feature is "year auto correction". It means you can set
>         such database params as CenturyBound and Century for getting proper
>         dates, putting ones in "short-year" forms.
> 
>         Also you can set own date and time separators and choose date format
>         for comfortable usage. It is possible to change those params at any
> time.
>         ( Please note - you should use current datetime format in any queries,
>         expected values and methods' text. )
> 
> 
>      2. "date", "time", "datetime" keywords. What is it for.
>         Where it must be used and so on.
> 
>         The first two keywords are from SQL-92 standard, the third is
> Valentina
>         SQL-syntax extension.
> 
>         You HAVE TO use these keywords in methods predicates
>         in case you need to define datetime-literal.
> 
>         Example:
>           There are samples of method's text:
>                 "fld1 <> date'2004-01-01'"
>                 "fld2 = time'16:00:00'"
>                 "fld3 < datetime'2004-01-01 01:00:00'"

Question: how in literal we specify the milliseconds?
It seems after DOT?

                 "fld3 < datetime'2004-01-01 01:00:00.123'"
    

>         Also, you CAN use these keywords in any other places. For example:
> 
>         "YEAR(date'2004-01-01')"
>         "... where fld1 > date'2004-01-01' "
> 
>         but
> 
>         "YEAR('2004-01-01')"
>         "... where fld1 > '2004-01-01' "
> 
>         are also allowable.
> 
>         Strict usage of such keywords must be only in methods' predicates
> based on
>         datetime-literals.
> 
>         
>      3. There is powerful set of datetime SQL-functions in Valentina 2.
>         I would say this is a most powerful set in DBMS world.
>         
>         

-- 
Best regards,
Ruslan Zasukhin      [ I feel the need...the need for speed ]
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e-mail: ruslan at paradigmasoft.com
web: http://www.paradigmasoft.com

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