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7

For single node Oracle RDBMS installations, an SCN is never duplicated. With older versions of Oracle RAC, Oracle 9i for example, it was possible that two transactions, running on separate RAC nodes, could end up with the same SCN. Duplicates happened only in rare situations where high transaction rates on the RAC nodes was coupled with a large value for ...


5

In Oracle all set operators currently have equal precedence and are evaluated from top to bottom. SELECT 1 FROM DUAL UNION ALL SELECT 1 FROM DUAL; Returns two rows with both columns containing 1. But minus operates similarly to union (as opposed to union all) and removes duplicates so distinct-ifying the result. One way of getting the result you ...


2

I'm sure this has already been asked before, but .. from the Oracle documentation Further down the page, when you look for what each constraint state is: VALIDATE | NOVALIDATE The behavior of VALIDATE and NOVALIDATE always depends on whether the constraint is enabled or disabled, either explicitly or by default. Therefore they are described in the ...


1

It only allows access to data dictionary views, so the only security implication is that the users(s) would be able to see which objects existed in the other schemas. They would not, however, be able to actually view the data in the other schemas. I said there was only one security implication, but another is that they would be able to view the source of ...


1

JOIN is not that effective, because you need to access the table 4 times. With PIVOT you can do it with 1 table access. create table list_of_stuff ( list_id number(5,0), item varchar2(40 char) ); insert all into list_of_stuff values (47, 'Baseball') into list_of_stuff values (47, 'Hat') into list_of_stuff values (47, 'Gloves') into ...


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Martin Smith addressed a possible solution if you don't need to union before you minus (which I'm not sure will work for what you intend).. If you need to UNION first before you MINUS, while still preserving duplicate rows, then I think you'll have to do something along these lines: SELECT * FROM ( SELECT 1 as col1 FROM DUAL UNION ALL SELECT 1 as ...



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