Masking in Oracle
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Oracle has recently introduced masking as one of the facilities. Masking allows data to be hidden from users / or only display part of the content. Other users can still…
Variables in Oracle
The question is simple: we have an Oracle query and we want to use one search criterium as a parameter. Let us take a simple example. We want to use…
a view with security
One may implement security by creating a view. This view then only contains the columns that you would like to show. If one adds a filter, one may also limit…
drop Oracle table
Oracle knows the command “drop table”. One may include this in a script where a table is first deleted (using “drop table”) and subsequently rebuilt with additional SQL statement. But…
External tables in Oracle
External tables allow someone to store data in a file while these files are shown as tables within Oracle. So, we have a two sided object – on one hand…
Analysing JSON and database tables in Spark
In a previous note, I showed how CSV files can be analysed. One may use the same technique to analyse JSON files or tables in a database. First, analysing JSON…
Processing CSV files in Spark
It is possible to process CSV files in Spark as if these files are tables. That looks very promising: reading a file, translating the file into something that can be…
Install Spark on windows
I found a beautiful YouTube movie that showed how Spark can be installed on windows. I found this on https://www.youtube.com/watch?v=WlE7RNdtfwE . The movie provided a clear guide how to this…
Useful Scala Programme
I saw a small Scala programme that allows you to calculate subtotals. The idea is that a flat file is provided with a name and a subtotal. A given namen…
The tango between Hive and Impala
An interesting tango exists between Hive and Impala. The situation is as follows. Hive acts as an layer upon map reduce. It provides an interface whereby table definitions can be…