Duplicates
Digression: Metadata of query results
Example 2
jao=# create table dups_ok(x int not null, y int not null);
CREATE TABLE
jao=# \d t
Table "public.dups_ok"
Column | Type | Modifiers
--------+---------+-----------
x | integer | not null
y | integer | not null
jao=# insert into dups_ok values (100, 200), (100, 200);
INSERT 0 2
jao=# select * from dups_ok;
x | y
-----+-----
100 | 200
100 | 200
Things to notice:
- No PK declared.
- No PK in metadata, (Postgres permits such tables, and didn't fill one in).
- Duplicates permitted.
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