Re: Oracle 9i features?

more comments in-line

• mcs

"Sybrand Bakker" <sybrandb_at_hccnet.nl> wrote in message news:3hb920dp1gb3lvphn0363vv8jatgi4c3bv_at_4ax.com...
| On 7 Feb 2004 00:39:22 -0800, pascaldamian_at_icqmail.com (Pascal Damian)
| wrote:
|
| >Could someone confirm or answer whether Oracle 9i has the following
| >features?
| >
| >* Can we define several user function (CREATE FUNCTION) that have the
| >same name but with different signature (for example, REVERSE(varchar)
| >and REVERSE(blob))?
|
| has been present since V7

but only within packages

|
| >
| >* computed field/column is not supported, use VIEW for that purpose;
|
| Has been supported all the time
| >
| >* Can columns on a VIEW be indexed?
| Only tables can be indexed

however, so other post on materialized views, plus oracle supports function-based indexes, so indexes can be created on expressions (but the target is still the table)

| >
| >* Only READ COMMITTED and SERIALIZABLE transaction isolation level are
| >supported; READ UNCOMMITTED and REPEATABLE READ are not.
| >
|
| please read the Oracle Concepts Manual. In Oracle readers don't block
| writers

often a different mindset for between Oracle and non-Oracle RDBMS developers/designers -- don't try to make Oracle (mis)behave like MS-SS and that SY-brand database (been waiting along time to use that bad pun!)

| >* Can a unique index accept multiple NULLs?
|
| Yes

as it should -- since a null is be definition unknown, the RDBMS should not assume that two or more unknown values are equal, thus dissallowed

| >
| >* Maximum number of indexes per table?
|
| No limits, but unlimited indexes will likely have the optimizer choose
| the wrong index and impair insert/update performance
| >
| >* An index can be defined on RAW (but not LONG or LONG RAW) columns.
| yes it can
|
| most of your questions are easily answered by doco, please do not
| treat this forum as a substitute
|
| --
| Sybrand Bakker, Senior Oracle DBA
Received on Sat Feb 07 2004 - 06:51:59 CST