Learn Oracle http://www.kods.net/ Learn Oracle Wed, 10 Mar 2010 15:24:13+0000 http://www.kods.net/ en --- Training to learn Oracle DB10g of experience http://www.kods.netwww.kods.net/training-to-learn-oracle-db10g-of-experience/ http://www.kods.netwww.kods.net/training-to-learn-oracle-db10g-of-experience/#comments Sat, 02 Jan 2010 16:00:05+0000 kods.net http://www.kods.netwww.kods.net/training-to-learn-oracle-db10g-of-experience/ rn

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Here are some of the interview may be asked to:
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1, the database of the five kinds of common basic object
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Tables, sequences, synonyms, indexes, views
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2, truncate, and drop the distinction between
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truncate in fact there is no effect of the conditions of delete statements as the result is to delete all the data in the table, but truncate after the implementation of the release of a certain space, delete will not be released; and truncate, and drop the difference is that, truncate table delete table data not damage the table structure, but the drop table structure will be destroyed. Therefore, the caution drop table; unless you're sure this table abandoned. Speed of execution are: drop> truncate> delete.
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3, four basic characteristics of transaction (ACID)
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Atomicity, isolation, consistency, permanent
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4, Oracle in the transaction isolation level
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read uncommited, read commited, repead read, serializable
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5, sql in the set operator
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UNION combination of each query to return all the rows, and delete the duplicate rows.
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eg. select * from emp where deptno = 10 UNION select * from emp where sal> 500
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UNION ALL combinations for each query returns all rows, and includes duplicate rows.
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eg. select * from emp where deptno = 10 UNION ALL select * from emp where sal> 500
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MINUS query returns with the first row, minus the second query return the same rows, and return the remaining rows
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eg. select * from emp MINUS select * from emp where sal> 500
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INTERSECT returns only rows returned by two queries together
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eg. select * from emp where deptno = 10 INTERSECT select * from emp where sal> 500

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