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Tuesday, 3 October 2017

Drop Column in Oracle Table


Used to remove column from existing table
 
Syntax:
        Alter table <table_name> drop <col  datatype>;
Example:
ALTER TABLE student DROP COLUMN srno;
ALTER TABLE student DROP (phone,email);
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3 comments:

  1. Hi There,


    Great info! I recently came across your blog and have been reading along.
    I thought I would leave my first comment. I don’t know what to say except that I have

    We have a linked server "LinkSQL" defined on SQLServerA against the same server, ie, SQLServerA and the server has Named Pipes disabled. Isn't communication among'st applications within one server happens primarily through Named Pipes. If so, would it be better if we have Named Pipes enabled on this SQLServer box?
    We are seeing intermittent TCP/Semaphore errors and I was wondering if enabling this option would help.
    But nice Article Mate! Great Information! Keep up the good work!


    Thank you,
    Danny

    ReplyDelete
  2. Hi There,


    So bloody thorough! Ah! So happy and blessed out! I feel redeemed by reading out Drop Column in Oracle Table Keep up the good work!

    I got a list of the INDEXES from DBA Team which are non value added to the Database with the following conditions
    Quote:
    1:Low selectivity indexes.
    2:The number of distinct key values is less than 10 and the number of rows in table in greater than 100000.
    3:All these normal(Balances -Tree )indexes.
    They are asking the App Team to review these and to drop those indexes.
    But when I analyzed those indexes some of the columns are using in the where conditions of the so many queries.
    After applying the HINT of those indexes also the cost of query was decreasing.
    Here my confusion was, if we really drop those indexes, will it increase the performance?
    or
    Do we need to convert those as BITMAP as they have low cardinality ?

    Please help me to understand the concept behind this .

    Thank you very much and will look for more postings from you.


    Thanks and Regards,
    Cavin

    ReplyDelete
  3. Hi There,

    In debt to you for making my learning on the Drop Column in Oracle Table area so hassle-free! I lay my faith on your writings.
    I am facing one ora-error while executing the procedure.
    ORA-06512: at "Lax.CLOSE_DUP"
    ORA-06502: PL/SQL: numeric or value error: character string buffer too small

    i am suspecting it could be length issue with some of variables i have declared inside procedure
    l_effectreqcount number;----> This is tracking no of records being fetched.
    l_postdata varchar2(999); ---> This is the variable for which i believe the error has come.
    The reason is that in this variable l_postdata I am concatenating all the data being fetched from cursor.it is something like this.

    THANK YOU!! This saved my butt today, I’m immensely grateful.

    Cheers,
    Preethi

    ReplyDelete