Does Oracle automatically create a unique index for PK ?

[ben oliver]

I am using oracle 10g XE. When I use the GUI to create a table and specify a PK. It shows that the script automatically creates a constraint for this PK. This makes sense. Then I found that when I pick "index" button, I saw this index whose name is identical to the PK name. So does Oracle 10g automatically creates such a unique index using this PK for me ?

[Jeanne Boyarsky]

Ben,
Yes, Oracle creates an index automatically on the primary key column(s).

[ben oliver]

Thanks for the reply. Since I didn't know Oracle automatically creates index for its PK. I manually created "another" index on the PK using a different index name

create unque index "MY_TABLE_INDEX" on "MY_TABLE"(ID);

Does this duplication cause any problem ?

[Jeanne Boyarsky]

Ben,
No problem. It does use some extra disk space, but won't interfere with the running of queries.