On Mon, 28 Jan 2002, Marc Mitchell wrote: > pgsqlPostgres automatically creates a unique index to assure data integrity > (see CREATE INDEX statement). > > The online docs at > http://www.postgresql.org/idocs/index.php?sql-createtable.html state the > following: > > " Postgres automatically creates a unique index to assure data integrity > (see CREATE INDEX statement). " ... when PRIMARY KEY is specified within a > CREATE TABLE statement. > > My questions: > > 1) Are these indexes at all visible to a tool like PGAdmin? How are they > named?
The name is <table>_pkey. I'd assume they are visible assuming PGAdmin doesn't hide them and just show the primary key constraint. > 2) If FORIGN KEY constraints were present on tables, I assume a lookup is > done at time of INSERT to ensure the referenced value can be found. Would > such a lookup and the index used be seen in the EXPLAIN or EXPLAIN VERBOSE > output of an INSERT? It should generally use the index. There are cases due to the saved plan where the best plan might change during a session and we won't notice that until the next session. The explain output won't show the fk lookups as far as I know, however. ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
