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Thread: Back to Oracle

  1. #1
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    Unanswered: Back to Oracle

    Hello,

    I've been working with SQL Server for the past 5 to 7 years. The last time I worked with Oracle is 10g during it's early stages. How much has changed in 11 and 12 since then? With an intermediate database administration and development background, would I have a steep learning curve to catch up to 11 and 12? I'm back in the job hunting market, and am curious what I would face in an Oracle oriented interview.

    Thank you in advance.

  2. #2
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    What do you consider to be some of the major differences between Oracle & SQL Server?
    You can lead some folks to knowledge, but you can not make them think.
    The average person thinks he's above average!
    For most folks, they don't know, what they don't know.
    Good judgement comes from experience. Experience comes from bad judgement.

  3. #3
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    Interface, Structure, Language

  4. #4
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    Consider to read the New Features manual for both V11 & V12 Oracle database
    You can lead some folks to knowledge, but you can not make them think.
    The average person thinks he's above average!
    For most folks, they don't know, what they don't know.
    Good judgement comes from experience. Experience comes from bad judgement.

  5. #5
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    Coming from SQL Server, I can attest that the transition to Oracle is not an easy one. Things that you take for granted in SQL Server you have to work
    at it in Oracle. If you were someone who started with Oracle or had significant training in Oracle, then you would just accept everything as normal
    and you wouldn't know any difference. Oracle has a lot of objects that SQL Server does not have such as Materialized Views (SQL Server has just Views),
    Identity columns counters are in different objects called sequences not embedded in the table like SQL Server, to do a simple SELECT with calculation not coming from table, you have to say FROM DUAL in Oracle (SQL Server you can just say SELECT 2+3 versus SELECT 2+3 FROM DUAL). There isn't a tool like SQL Server Profiler. There are monitoring tools but they just don't work like the Profiler. Setting up an Oracle instance is way more complex. Doing things like creating a new database instance is not straight forward. Google queries for Oracle issues is just a pain and you will be lucky to find a solution that fits you situation. Many people would say Oracle is just a way more mature or grown-up database hence the complexity of things. I just know I never went through the kind of pain with SQL Server that I have with Oracle. But my job demands that I work in both areas. So I am forcing myself to learn Oracle the best that I can.

    I know my response wasn't exactly about changes since 10g but just an overall experiece with Oracle. Good luck on your interviews.

  6. #6
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    Quote Originally Posted by VbMan View Post
    Things that you take for granted in SQL Server you have to work at it in Oracle
    I believe that vice versa is true as well.

    Identity columns counters are in different objects called sequences not embedded in the table like SQL Server
    Not really; not in 12c, that is. It introduced identity columns.

    ... you have to say FROM DUAL in Oracle
    Right; DUAL is really cool and can be used for many purposes.

    Setting up an Oracle instance is way more complex ...
    I like what John Watson says on OraFAQ forum:
    Quote Originally Posted by John
    I think that Oracle databases are more prone to the issue of incompetent people performing responsible jobs than many other environments, because the database is so rock-solid reliable and can be largely self-administrating. That is why people buy it (and why it is so expensive). I called myself a DBA for years when I was really just a hacker. You can get away with it. Many people claim to have administered a database for years with no problems, when all they have been doing is watching it administer itself.

  7. #7
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    Quote Originally Posted by VbMan View Post
    Things that you take for granted in SQL Server you have to work
    The opposite is true as well.

    It always strikes me as being extremely strange that in a default installation of SQL Server you can not read and write to the same table from two different transactions. The level of locking in SQL Server is simply ridiculous for a long time Oracle user. Granted this is better now that there is the "read committed" setting but concurrent reads and writes are still way less problematic in Oracle (Oracle has no lock escalation for example where all over sudden a table is locked just because I updated many rows).

    You should also not forget that Oracle already existed nearly 20 years when SQL Server arrived. Oracle was able to do recursive queries or window functions since the late 80s. SQL Server was very late to that party.

    I do admit there are some nice features in SQL Server that I'd like to see in Oracle (transactional DDL is one) - but the other is true as well. Regular expressions or deferred constraints are something I really miss in SQL Server. Or the ability to create an index on an expression (indexing a computed column is a workaround, but requires a table lock because of the ALTER TABLE). And it took them until 2014 to be able to format dates properly. And what's with that ridiculous rule that a WITH must be preceded with a semicolon - which is the statement termination character, not some kind of prefix.

    Oracle has a lot of objects that SQL Server does not have such as Materialized Views (SQL Server has just Views),
    SQL Server has indexed views which are essentially the same, but without the query rewrite magic.

    Identity columns counters are in different objects called sequences not embedded in the table like SQL Server
    And SQL Server has sequences as well. I have seen several statements that claim that they are faster than identity columns.

    Setting up an Oracle instance is way more complex
    When was the last time you installed Oracle? The graphical installer takes about 10 clicks or so and everything is up and running. Not mentioning the ability to install it on Linux. What I also like is that you can download and install even the Enterprise Edition to test it and use it for development (No time limited trials, you get the full thing). If you are developing software and have to pay the Microsoft Enterprise license just to be able to test the deployment scripts for your customer, this is getting expensive (granted: it's way cheaper than an Oracle Enterprise license).

    I just know I never went through the kind of pain with SQL Server that I have with Oracle
    For me it's just the opposite.

    The problem is, when you use ToolA with the mindset of ToolB - you are bound to get problems (I too am guilty of that way too often). I'm pretty sure an Oracle expert will write SQL code that will bring SQL to a screeching halt. And most usage pattern in SQL Server (e.g. the need to put everything in a temp table and go from there to avoid locks and concurrency) will leave you with a crawling Oracle.

    Both are mature and good products (SQL Server only after 2008 from my point of view) but if you use them incorrectly and don't try to understand how to work with the specifics of each product, both will disappoint you.
    I will not read nor answer questions where the SQL code is messy and not formatted properly using [code] tags: http://www.dbforums.com/misc.php?do=bbcode#code

    Tips for good questions:

    http://tkyte.blogspot.de/2005/06/how...questions.html
    http://wiki.postgresql.org/wiki/SlowQueryQuestions
    http://catb.org/esr/faqs/smart-questions.html

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