Primary key or Index ?

[Pal Coder]

Hi,

I have a table contains 80.000 rows approx and I set (id) field to be primary key and index by using phpmyadmin.

my question is that right ? or it must be primary key or index not both

[oranjcrush]

Yes, you did the right thing. IIRC a Primary Key is just a special form of a UNIQUE INDEX in MySQL

[r937]

if you made it both the primary key and in index, then the index is redundant

a primary key is an index, so the extra index is not needed

[Pal Coder]

thank you

but, when i did this (both). The search in the table would be slowly or would not affect at search speed ?

[r937]

redundant indexes do not affect search speed, they just makes inserts, updates, and deletes slower

[Pal Coder]

r937, thank you