Category Archives: Uncategorized

Partitioned Table in Hive

It is possible to partition the tables in Hive. Remember the data are stored in files. So we expect the files to be partitioned. This is accomplished by a split of the files over different directories. One directory serves one partition, a second another partition etc. Let us take the example of 7 records that… Read More »

Manipulating Avro

Avro files are binary files that contain data and the description of the files. Thereby it is a very interesting file format. One may send this file to any application that is able to read Avro files. Just as an example: one may write the file is (say) PHP and send it to (say) Java.… Read More »

Parquet format

As we know, we may store table definitions in the metastore. These table definitions then refer to a location where the data are stored. The format of the data might be an ordinary text file or it might be an avro file. Another possibility is a parquet file. This parquet format is an example of… Read More »

Avro format

In Hive, we see a situation where a table definition is stored in a metastore. This table definition is linked to a directory where the data are stored. It is possible to use different formats here. One may think of a text format. But other formats are possible too. One example is the avro format.… Read More »

Create a Hive table – 3 ways

In this little note, I want to show three different ways to create a table on Hive. The first one starts with a file on HDFS that is available and we create a table upon this file. This table is defined as an external file that is exposed as a table. The code to be executed… Read More »

Oracle ODI

The successor to OWB is the Oracle Data Integrator. This tool has more functionalities than OWB. Next to that, it has an interface that more or less steers the user through a series of steps. The idea is that one starts with a technical view where the file locations, databases and schemes are declared. Once… Read More »

Docker container

Only this weekend I downloaded a Docker package from This package allows you to run very small light weight containers on your server than act as components to perform a certain task. In a way, it looks like a virtual machine. It has no direct connect connection to the host machine and it runs… Read More »

Putting a file on HDFS

Putting a file on HDFS is relatively easy. There are a few steps to take. Let us assume the file is on a linux system. The first step is to copy the file to an area where it can be stored with the hdfs user as its owner. On my system, I have /tmp that… Read More »

Estimating with Python

It is relatively easy to do an estimate with a Python script. This is due to the fact that Python works with matrices and such matrices can be used as an input in a estimation procedure. I created an example where a dataset is retrieve from Oracle. Then the dataset is translated into a matrix.… Read More »

Read and write by Python

Python seems to be a very convenient way to transfer data to and fro Oracle. It has capabilities to set up a connection and it seems quite capable to transfer a matrix into a table and vice versa. Next code shows this. It first retrieves the content of a table. In a second step some… Read More »