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Android App for Data Warehousing and Big Data at #oow15

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A number of people have asked if I could make a smartphone app version of my usual OpenWorld web app ( OpenWorld 2015 on your smartphone and tablet ) which does not require a data or wifi connection. For Android users there is some good news: here is my new Android app for OpenWorld that installs on your smartphone and runs without needing a wifi connection or a mobile data connection. This  DW and Big Data app  is nice and small so it is quick to download and install onto your phone. It contains everything you need to know about data warehousing and big activities at OpenWorld. The app has sections for: Key Oracle Speakers - arranged by category  Data warehouse and big data sessions by Oracle product managers, key partners and customers. Organized by category and day-by-day Hands on Labs. Organized by category and day-by-day Maps to help you find your way around Moscone and the surrounding area To download the Android app click here:  DWBDoow15...
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Exploring the interfaces for User Defined Aggregates

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  image courtesy of wikipedia Whilst I was working on the functional specification for the LISTAGG extensions that we implemented in 12c Release 2, I came across Tom Kyte’s stragg function  which uses the User Defined Aggregate API introduced in database 9i. Tom’s comprehensive answer covers the two important areas that need to considered when using the data cartridge API: 1) a UDA can run as serial process and 2) a UDA can run as a parallel process. Therefore, you need to code for both these eventualities. Dealing with both scenarios can be a little challenging - as I have discovered over the last few weeks. having looked at a number of posts there is a common theme for explaining how the various interfaces for user defined aggregate actually work. One the clearest examples is on Tim Hall’s blog:  String Aggregation Techniques . This got me thinking…would it be possible to take the new  extensions we made to LISTAGG and incorporate them into custom string manipulation func...
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Managing overflows in LISTAGG

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This is an interesting problem that has come up a few times in discussions (and I think it has been mentioned on the SQL forums as well).  When using LISTAGG  on very large data sets you can sometimes create a list that is too long and consequently get an ORA-01489: result of string concatenation is too long   error . Obviously, it is possible to determine in advance if the error is going to occur using some bespoke PL/SQL code and then take appropriate action within your application to manage the rows that contain stings that exceed the VARCHAR2 limit. Many customers have implemented workarounds to overcome the  ORA-01489  error, however, this has mostly involved the use of complex code which has impacted performance. Wouldn’t it be great if there was a simple yet elegant way to resolve this issue? Actually there is and we can use a few of the most recent analytical SQL functions. If you are using Database 12c you can make use of the  MATCH_RECOGNIZE  function to effecti...
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