Category Archives: SQL

Benefits and consequences of the NOLOGGING option

I still find confusion out there about the LOGGING and NOLOGGING clauses when performing DML and DDL operations, the reality is that the NOLOGGING clause will work only on particular conditions, but all regular inserts,updates and deletes will still log … Continue reading

Posted in Backup & Recovery, Oracle Server, SQL | Tagged , , , , , , , | 9 Comments

UNDO management, Cannot shrink the UNDO tablespace.

One common question we can  find in the internet is how to shrink the undo tablespace, because even if we see it empty we can get an ORA 3297 error (see here how to deal with ORA 3297 error), therefore, … Continue reading

Posted in Oracle Server, SQL | Tagged , , , , | 2 Comments

ORA 3297 when resizing a datafile

ORA 3297 when resizing a datafile December 2, 2009 · Leave a Comment · Edit This Sometimes we want to shrink a datafile and we get the ORA-3297 error, what? but if there is enough space!! Well , there is … Continue reading

Posted in Oracle Server, SQL | Tagged , , , , , , , | 1 Comment

NVL Tips: Is it possible to run a query if the result of a first one is null?

How to run a query when the result of the first one is null, powerful examples with NVL Continue reading

Posted in SQL | Tagged , , , , , | 2 Comments

Multi table Inserts

Since Oracle 9 we can perform multitable inserts, allowing us to distribute the data from one source in one or more tables. For the first example we have a sales table (can be external or remote) like this: SELECT * … Continue reading

Posted in Oracle Server, Schema, SQL | Tagged , , , , , | 1 Comment