Re: Oracle Problem from a beginner

Chung Wing Tat Áéºa¹F wrote:
...
> I am a beginner of Oracle in Hong Kong, I have a table which structures
> are listed as follows:
>
> ref_no varchar(8)
> date_from date
> date_to date
>
> I need to setup a constraint to this table to ensure that there is no
> overlapping date range in all rows...

For date ranges, we use a structure like this:

ref_no		varchar(8)
effdt		date

This way, the range is defined by the dates between a row's effective date and the next most recent row's effective date, and overlaps can't happen.

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