Обсуждение: Example for Unique Partial Indexes

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/16/indexes-unique.html
Description:

I would like to request an improvement to the PostgreSQL documentation,
specifically in the sections "11.6. Unique Indexes" and "11.8. Partial
Indexes."

Currently, the documentation does not provide information on how to create
unique partial indexes. Unique partial indexes are valuable for enforcing
uniqueness of a column's value over a subset of a table.

To enhance the documentation's completeness and to provide a clear example
for users, I propose adding an entry in one of these sections with an
example as follows:

```sql
Copy code
-- Example of Creating a Unique Partial Index
-- This index enforces uniqueness of the 'column' over a subset of the
table
CREATE UNIQUE INDEX name ON table (column [, ...]) WHERE (condition);
This addition will assist users in understanding how to create unique
partial indexes and help them enforce uniqueness over specific subsets of
their tables. Please consider incorporating this addition into the
documentation.
```

Thank you for your attention to this request, and I believe it will
contribute to the clarity and comprehensiveness of the PostgreSQL
documentation.

"David G. Johnston" <david.g.johnston@gmail.com> writes:
> On Tue, Nov 7, 2023, 09:25 PG Doc comments form <noreply@postgresql.org>
> wrote:
>> Currently, the documentation does not provide information on how to create
>> unique partial indexes. Unique partial indexes are valuable for enforcing
>> uniqueness of a column's value over a subset of a table

> 11.8 discusses this in detail including an example.  Maybe should add a
> forward reference from 11.6 though.

Yeah, AFAICS 11.8's coverage of this point is perfectly adequate.

I'm disinclined to add a forward reference, because 11.8 is the
first section that mentions partial indexes at all.  Somebody
reading the chapter in order would have no idea what we were
talking about.

            regards, tom lane