SQL server vs ORACLE

[prodadmin]

Hi

I guess this question is out of this forums but please answer
if you can.

i am working on oracle for last 3 years and never ..never worked or saw SQL server ,could any one please let me know how many days it will take to learn sql server and how difficult it and any websites???

[venudba]

It takes very less time. Probably you could learn thoroughly with in a week.
Because everything you can manage by GUI. It's like a Plug and Play.

[pando]

you only have to learn how to use Enterprise Manager, took me 10 days and it is REALLY boring

God bless me I left the place where I had to to use sql server

[venudba]

It takes very less time. Probably you could learn thoroughly with in a week.
Because everything you can manage by GUI. It's like a Plug and Play.

[prodadmin]

Thanks guys for giving some positive thoughts!!!

[gee]

I have been working with SQL Server since the first version ported from Sybase (4.5).

As indicated above, basic adminstration using Enterprise Manager won't take someone familar with rdms long to learn.

Creating databases, tables, view, indexes can all be done using a drag and drop approach within Enterprise manager.

Writting db triggers requires a bit of digging into the documentation and understanding T-SQL, but again it shouldn'
t take you more than a few hours to figure this area out.

If you need to write some stored procedures you will need to put more effort into learning T-SQL as it is different the PL/SQL. All the concepts are the same (i.e. Open a cursor, loop through, etc), but the syntax and function names are different (i.e. to_char() vs convert() is different.

[padmam]

Dear Friend, 26th sep 2001 17:46 hrs Mumbai

Welcome to DBAsupport.com as a New Member.

This is to inform that "How to Forum" is Not to Raise
DBA Problems instead it is for posting Solutions for COMMONLY occuring Problem
in Oracle Data Base.

You can Post your problems in future in "Oracle Database Administration" Forum
where you can find lot of friends to solve the same.

I am also moving the this thread to Oracle Database Administration Forum.

Cheers

Padmam.

[tamilselvan]

SQL Server Vs Oracle

As a Tech Guy I am pointing out the differences between SQL Server and Oracle. They are:
Dirty Reads
SQL Server supports dirty reads. It means data changed by first transaction can be seen in the 2nd transaction even though the first transaction has not committed or rolled back the entire transaction. Example in SQL server:
In the Query Analyzer, enter the first transaction:
Begin transaction
Update EMP set deptno = 60 where deptno = 10
Now open another Query Analyzer for the 2nd transaction:
Select * from EMP
If you try to run 2nd SQL statement, then it won’t be executed because the previous transaction has not yet committed or rolled back. SQL server will wait till the completion of 1st transaction because of the isolation level is set to read committed.

Now, add (NOLOCK) to the Select statement.
Select * from EMP (NOLOCK)
This statement is immediately executed and the result set would display the updated rows from the first transaction. This is called dirty read in SQL Server.
Where as Oracle did not support dirty reads. For the 2nd transaction Oracle uses pre-images of the data being modified by first transaction from the rollback segments.
Bank transaction needs dirty reads that are possible in SQL Server but not in Oracle.
One more caution:
SELECT * FROM EMP WHERE SALARY = NULL ; is allowed in SQL Server 7, where as "= NULL " is not allowed in Oracle Select statement.

Isolation Level
SQL Server is designed for higher isolation level.
The level at which a transaction is prepared to accept inconsistent data is termed the isolation level. A lower isolation level increases concurrency but at the expense of data correctness. Conversely, a higher isolation level ensures that data is correct, but can negatively affect concurrency. Oracle is just opposite of SQL Server.


Partitioning Table.
Table level Partition is not supported in SQL Server 7. If you have a big table (say 1 B rows), then you have to manually create small tables (say 10 tables with 10M rows), and use a view that has UNION of all small tables to access the full table. This is not the case in Oracle. Oracle supports Range, Hash and composite partitioning.
Image data (BLOB, CLOB etc )
Maximum size is SQL Server 2 GB
Maximum size is Oracle 4 GB
Columns per Index
In SQL Server 16
In Oracle 32

Outer Join
SQL server supports full outer joins (left and right) where as Oracle supports one way outer join only. More over it works just opposite in both RDBMS. For example, in SQL Server the left outer joins statement looks like:
Select * from emp a, dept b where a.deptno *= b.deptno
If you want the same result set in Oracle, you need to write as given below:
Select * from emp a, dept b where a.deptno = b.deptno (+)

Set Operator DIVIDEBY (DIVISION)
Both RDBMS do not support DIVISION set operator. I have been waiting for this facility since 1985. I do not know why it is not supported in Oracle as well as in SQL Server.

Platform availability
SQL Server is available only on NT / W2K OS where as Oracle is available in almost all platforms.

Administration
It is easy to administer SQL server because of its size and its GUI tool. Oracle needs experienced DBA to administer a very large database.

HOT BACKUP
Both RDBMS support hot backup.

Replication
It is supported in both RDBMS.

SEQUENCE
Sequence is defined at the table level in SQL Server, where as it is a separate object in Oracle.

24x7 Availability
Both RDBMS can be run 24x7 as long as the hardware is good. I had seen many big Oracle databases crashed because of the poor hardware setup. At the same time I had seen medium sized SQL Server databases running continuously (24 x 7) on a very good Compaq and IBM servers.
Rollback Segment
No more Snapshot too old error message. Oracle finally is going to get rid of this concept in 9i. Has any one tested? In 9I, only a tablespace would be designated for rollback area. No need of creating Rollback segments. There is NO Rollback Segment concept in SQL Server. It uses LOG file for its roll back activity.

I have pointed out the tech details of both RDBMS. Okay. Which one is superior? I leave the answer to DBAs. If your database is going to be small, and only few concurrent users use the database, and you do not want to spend more money, then go with SQL Server. On the other hand, if your database is going to be big, and you have a large user population, then choose Oracle. If you want to build a Data Warehouse of size over 3 TB, then go with Teradata.

[elaine3839]

Hi tamilselvan,

Since I can't find a way to e-mail you directly, I'd like to just add another post to this thread.

I work for a software company which supports both Oracle and SQL server. Since my Oracle background is stroner than SQL, I've been looking for a way to improve my SQL Server knowledge for a while.

So do you happen to know a good SQL admin forum which could serve as a counterpart of dbasupport.com for sql? I searched the web a couple of times, but haven't found anything that is comparable to this.

Any idea?

Thanks a lot,
Elaine

[Sureshy]

Hi Elaine..

Try sqlmag.com

May take a little longer to get reply than this site, is a bit slow in performance and is subject to downtime, never the less you will get an answer to most questions eventually.