The second is shorthand for the first. you get to choose the index name
in the first one.
Ian Harding
Programmer/Analyst II
Tacoma-Pierce County Health Department
iharding@tpchd.org
Phone: (253) 798-3549
Pager: (253) 754-0002
>>> Scott Frankel <leknarf@pacbell.net> 12/01/04 10:48 AM >>>
1.
CREATE TABLE names (the_id SERIAL PRIMARY KEY, the_name text);
CREATE UNIQUE INDEX uidx_thename ON names(the_name);
vs.
2.
CREATE TABLE names (the_id SERIAL PRIMARY KEY, the_name text UNIQUE);
Is the UNIQUE constraint in the second solution merely short-hand for
the explicit
index declaration of the first solution? Or is there a functional
difference between
them that I should choose between?
Thanks again!
Scott
On Dec 1, 2004, at 10:11 AM, Scott Frankel wrote:
>
> I want to ensure data integrity when inserting into a table,
> preventing multiple
> entries of identical rows of data.
>
> Does this call for using a trigger?
> How would triggers perform a query to test if data already exists in
> the table?
>
> (The doco outlines how triggers perform tests on NEW data inserted
> into a
> table; but I haven't found anything on data already extant.)
>
> Thanks in advance!
> Scott
>
>
> sample table:
>
> CREATE TABLE names (the_id SERIAL PRIMARY KEY, the_name text);
>
>
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