Re: 2 Oracle doubts

Hi delavega, thanks for writing this:
> Hi. I´m a MySql programmer, but i need make a application with Oracle
> 8.1 Server. I have 2 doubts (for the moment)
>
> 1- Can i have a Oracle table without primary Key?
> 2- In a sql, the date fields are with quotas ("")? Exists the
> direct comparation between dates (<, >)?
>
> Thanks!
>

Several posts have asked why you want a table without a primary key. In a pure "data design" sense, that's a good question. However, in implementing a physical representation of your logical design, it's sometimes prudent to have a table without a primary key.

For example, we have a table that contains the two-character state abbreviation and its spelled-out (long) name. Unless something very unusual happens in the USA, there are only 52 rows in this table. Of course, I could use the state abbreviation as the PK (since it will be unique), or even use a sequence, but doing so would cause Oracle to generate an index for it. Now I know that all 52 states will easily fit in an Oracle block, so the optimizer will never use the index ... which means I've wasted space (not a lot of space, mind you).

We have other lookup tables that have things like status codes and descriptions. They also don't have a PK. A full table scan (in memory) on these small tables is not a serious performance hit. So, in conclusion, the answer is "it depends."

-- 
[:%s/Karsten Farrell/Oracle DBA/g]