I am coming from the SQL server world where we had uniqueidentifier. Is there an equivalent in oracle? This column will be frequently queried so performance is the key.
I am generating the GUID in .Net and will be passing it to Oracle. For a couple reasons it cannot be generated by oracle so I cannot use sequence.
CREATE table test (testguid RAW(16) default SYS_GUID() )
This blog studied the relative performance.
If I understand the question properly, you want to generate a unique id when you insert a row in the db.
You could use a sequence to do this. link here
Once you have created your sequence you can use it like this:
INSERT INTO mytable (col1, col2) VALUES (myseq.NEXTVAL, 'some other data');
GUIDs are not as used in Oracle as in MSSQL, we tend to have a NUMBER field (not null & primary key) , a sequence, and a trigger on insert to populate it (for every table).
There is no uniqueidentifier in Oracle.
You can implement one yourself by using RAW (kind of a pain) or CHAR. Performance on queries that JOIN on a CHAR field will suffer (maybe as much as 40%) in comparison with using an integer.
If you're doing distributed/replicated databases, the performance hit is worth it. Otherwise, just use an integer.
The general practice using Oracle is to create an artificial key. This is a column defined as a number. It is populated via a sequence. It is indexed/constrained via a primary key definition.