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Josep

Percentage of time series over its SMA (Simple Moving Average) compared against a weighted index

Problem with weighted indexes

One problem with weighted indexes is that few components of the index can move its value when the value of few components is much bigger than the others. That could give misleading conclusions. For example, when small weighted components are not following the trend of the big ones. Some scenarios where . . .

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October 09, 2018

Print Markdown in the HTML widget using Markdown package

I've uploaded a Jupyter Notebook in Github explaining two ways to print Markdown in a Jypyter Notebook:

The first option is straightforward, but the second one is much more powerful because can be used with other widgets, . . .

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August 17, 2018

A Brief introduction to YAML in Powershell

Missing an official YAML powershell module

I made another post about Powershell and YAML some months ago with more code where I explain the different ways to write YAML and how it behaves in powershell, comparing PSYaml and powershell-yaml modules.
After the experience of being working in a module that's compatible with both modules to read YAML files, I decided to write this . . .

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July 06, 2018

Change SERIAL to IDENTITY in PostgreSQL

PostgreSQL 10 implements SQL standard's IDENTITY

In SQL Server is quite common to use IDENTITYs for non-natural primary keys. In PostgreSQL, until version 10, only SERIALs could be used for the same purpose. But that has changed.

Why INDENTITY and not SERIAL and SEQUENCES?

SERIAL is a friendly way to set a SEQUENCE, but at the end, it's a SEQUENCE: an object that . . .

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Posted in: postgresql

February 27, 2018

Export data from Oracle to MongoDB in Python

Introduction

I had to export some data from an Oracle database to a MongoDB. For this reason I created a python function called export_data_from_oracle_to_mongodb that can be found in my Github.

To make the function more generic, I've there's an optional parameter called transform,where a function can be specified to . . .

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February 09, 2018

YAML in powershell

powershell doesn't have native support for yaml. Solution: PSYAML and powershell-yaml

UPDATE on 2018-07-06

I recommend reading my second post A Brief introduction to YAML in Powershell: it's shorter and has less code. It's done after working in a module that's compatible with powershell-yaml and PSYaml modules to read YAML files in Powershell.
I only recommend to read this blog if you're new to . . .

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Posted in: powershell

December 27, 2017

DEFERRED CONSTRAINTS in PostgreSQL

How to check consistency at the end of a transaction

Introduction

DEFERRED CONSTRAINTS are useful when you know that in a transaction you'll have inconsistent data for a while, like foreign keys that don't match, but you know that at the end of a transaction it will be consistent.

It was a nice PostgreSQL surprise to discover DEFERRED CONSTRAINTS, because it's not . . .

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Posted in: postgresql

December 19, 2017

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