January 25, 2011 at 8:03 am
I have a 'Root' table with 8 columns.
First 5 columns in 'Root table ' are used in all 10 child tables of that root table.
I first wanted to make the first 5 columns of the 'root' table as Composite Primary key ,
But the data thats going to come into the 5 columns will not be unique (like a column may have same hospital name with different patient numbers starting from 1,2,3----n in the patient column, When the hospital name changes in the Hospital column then the patient number again starts from 1,2,3----n ).
Note: Both the 'Hospiatal Name' & 'Patient number' are 2 columns among the 5 columns of the root table.
So as per my requirement ,Client wants to use all the first 5 columns of the root table in other 10 child tables also.
I am not able to do that as per the nomalization criteria.
Can anyone please suggest me how to design.
January 25, 2011 at 8:13 am
If I got you right you could:
Create an additional table with the 5 colums you mentioned. Add an artificial key to it (of type uniqueidentifier if possible).
Then, reference in every table to this key (also in your "root" table).
hope it helps. 🙂
January 25, 2011 at 8:25 am
A couple things, first, give some DDL and explain the differences in why the columns need. Second, don't consider the rows ordered. There isn't an order to the rows, necessarily, so don't consider that as part of your design.
A PK requires uniqueness. It enforces it, so if you set that, then you can't have duplicates. Building an index on those columns can help, but it does not need to be a PK. It can be an index to use for queries.
I tend to favor surrogate keys, like an identity column, if you are not sure of the data.
January 25, 2011 at 12:04 pm
well totally agree to steve .... it seams to be the best best
regards
greg
January 25, 2011 at 12:39 pm
-- removed xpost notice because Steve already pointed the other thread --
Good job, Steve
Johan
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