Re: Informix vs Oracle. SOme questions.

Hi there , U are working on Informix for a long period of time and it is highly unlikely that there will be one to one match to ur requirements. One has to look at the things which will be more beneficial than the ones that are less. Then again there will be issues which Oracle will handle very smoothly than Informix and vice versa. But in any case, I'll try to reply to ur queries as far as my knowledge goes --

> A rough draft of things our shop floor control system uses and must
> have. Not only because they currently exists. But, because they are
> Beneficial to our operation.
>
> * On occasions we need to recreate a table on the fly Quickly. These
> are situations where seconds and minutes are critical and can mean large
> dollar losses. Does oracle offer a tool to create a SQL statement of
> the table or entire entire database schema from the command line as
> easily as just typing "dbschema -d databasename" ?

ANS- Yes Oracle does offer tools like Designer/2000, Database Designer which can keep the database schema. And u can create the scripts for creation of database/tables.

>
> * Can database and tables be renamed using simple SQL ? "rename
> database abc to efg;"

ANS-Database can not be renamed easily but tables can be. This is because one Oracle instance opens only one database. But one database can be opened by different instances. - Oracle Parallel Server.

>
> * Sometimes we need to unload filtered data from a table to a flat file.
> we do this in simple SQL by simply executing commands such as "unload
> to filename select * from customer" Can I do this as easily in Oracle
> as I can now ?

ANS-Oracle has a very good tool for interactive sql which will allow u to do this.You can spool the results of a query to a flat file.

>
> * Also, we can unload databases or tables to ASCII or binary using tools
> such as dbexport, unload, onunload and a high performance loader which.
> We have been able to unload 8 million rows, drop the table, recreate it,
> apply 5 indices and reload the data in less than 30 minutes. Can Oracle
> do the same

ANS-Oracle's sql loader will allow u to do the loading as fast as u want with its direct path. I am not sure about the database download in ascii files. But the export of the database/tables can be done very easily and very fast.

>
> * We currently have several options for achieving data replication. from
> one server to another or from one to many. We currently use high
> availability replication which sends logical logs from one server to the
> other thus maintaining a real-time redundant server without having to
> setup any special database actions such as triggers or procedure to
> replicate for us. ( low maintenance ). Does oracle offer similar
> replication.

ANS-Oracle has one of the best replication engines. And it can be set up and maintained very easily by Oracle Replication Manager. All the above that u are doing can be done easily and above all there can be many master sites also. Which will open up many oppurtunities for u.

>
> * Is oracle 8 currently compatible with sql-92 ?
>

 ANS-I am not sure about this.
> * Does Oracle offer the ability to fragment a table by expression or
> round robin over multiple database spaces ? We have bench marked
> parallel processing in our labs with our current product which has been
> using the feature for several years now and have noticed performance
> gains of queries which took 3 minutes plus to 1 (one) second.
>

 ANS-U can do this easily in Oracle8.
> * I understand that when a database instance in oracle is set up, a
> fixed amount of memory is preallocated to the instance. What would
> happen when the system becomes saturated and more memory is needed ?
> Does it allocate memory dynamically ? Do I have to Bring down
> production, to allocate more memory and then restart ? Can I free up
> memory as easily as adding more ?

ANS-Yes u r right. U can not free up or add memory while database is runnning.

>
> * On the subject of bringing down the server, is it true that when a
> change to a parameter of the database is needed one must bring down the
> server and restart it ?

ANS-As u understand whatever changes u want in an instance, u have to shutdown and start up again to be in effect.

>
> * We put out software release on a regular basis. These release involve
> changes to tables. Currently if I alter a table and add a new column I
> can insert it before or after a specifics existing column. Can I do the
> same with Oracle using basic SQL. "alter table cust add ( state char (2)
> before zip );"

ANS-U can not add the column in between but there are 3rd party tools available to do this.

>
> * We use RAW disk partitioning for our database. This increases the
> performance of the IO. Does Oracle offer and SUPPORT RAW disk
> partioninig with oracle 7 or 8 ?

 ANS-Oracle supports the raw filesystem. (Not on all platforms.)
>
> * Does oracle offer automatic seamless char to numeric conversion and
> vice versa without the use of additional functions ?
 ANS-YES.
>
> * On our shop floor system everything is real time. Being so, we must
> capture dates and times down to a fraction of a second. these are
> regular data types which we use now. does oracle offer this data type ?
> or the interval type for differences between two time stamps ?
 ANS-It is DD-MON-YY HH:MI:SS but u can always create ur own datatypes.
>
> * Cursors allow a user to compile a Data Management Statement thus
> improving performance. Does Oracle support Dynamic cursors, meaning a
> user may fetch the last, previous, or an absolute element within a
> cursor ?
> *

ANS-There are cursors, but there are no previous, absolute, last fetch available.

I can go on adding the advantages but hey, there is not enogh time. It's almost 5 and I've to go home.

Ketan Shah
Sr. Consultant,
Mellon Bond Associates. Pittsburgh.

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