Kontext Column
local_offer windows10 local_offer hadoop local_offer yarn
This detailed step-by-step guide shows you how to install the latest Hadoop (v3.2.1) on Windows 10. It also provides a temporary fix for bug HDFS-14084 (java.lang.UnsupportedOperationException INFO).
local_offer hadoop local_offer hive
In this article, I’m going to demo how to install Hive 3.0.0 on Windows 10. Prerequisites Before installation of Apache Hive, please ensure you have Hadoop available on your Windows environment. We cannot run Hive without Hadoop. ...
local_offer python local_offer spark local_offer pyspark
Data partitioning is critical to data processing performance especially for large volume of data processing in Spark. Partitions in Spark won’t span across nodes though one node can contains more than one partitions. When processing, Spark assigns one task for each partition and each worker threa...
local_offer sqlite local_offer .net core local_offer entity-framework
SQLite is a self-contained and embedded SQL database engine. In .NET Core, Entity Framework Core provides APIs to work with SQLite. This page provides sample code to create a SQLite database using package Microsoft.EntityFrameworkCore.Sqlite . Create sample project ...
local_offer linux local_offer WSL local_offer ubuntu
This page shows how to install Windows Subsystem for Linux (WSL) system on a non-system drive manually. Enable Windows Subsystem for Linux system feature Open PowerShell as Administrator and run the following command to enable WSL feature: Enable-WindowsOptionalFea...
Save DataFrame as CSV File in Spark
local_offer pyspark local_offer spark local_offer spark-2-x
Spark provides rich APIs to save data frames to many different formats of files such as CSV, Parquet, Orc, Avro, etc. CSV is commonly used in data application though nowadays binary formats are getting momentum. In this article, I am going to show you how to save Spark data frame as CSV file in b...
local_offer hadoop local_offer yarn local_offer hdfs
This page summarizes the steps to install Hadoop 3.0.0 on your Windows environment. Reference page: https://wiki.apache.org/hadoop/Hadoop2OnWindows ...
local_offer python local_offer spark local_offer pyspark
In Spark, SparkContext.parallelize function can be used to convert Python list to RDD and then RDD can be converted to DataFrame object. The following sample code is based on Spark 2.x. In this page, I am going to show you how to convert the following list to a data frame: data = [(...
local_offer asp.net core local_offer identity core 2
The identity system in ASP.NET has evolved over time. If you are using ASP.NET Core, you probably found User property is an instance of ClaimsPrincipal in Controller or Razor views. Thus to retrieve the information, you need to utilize the claims.
Spark - Save DataFrame to Hive Table
local_offer python local_offer spark local_offer pyspark local_offer hive
From Spark 2.0, you can easily read data from Hive data warehouse and also write/append new data to Hive tables. This page shows how to operate with Hive in Spark including: Create DataFrame from existing Hive table Save DataFrame to a new Hive table Append data ...
Connect to SQL Server in Spark (PySpark)
local_offer SQL Server local_offer python local_offer spark local_offer pyspark
Spark is an analytics engine for big data processing. There are various ways to connect to a database in Spark. This page summarizes some of common approaches to connect to SQL Server using Python as programming language. ...
local_offer python local_offer spark
This post shows how to derive new column in a Spark data frame from a JSON array string column. I am running the code in Spark 2.2.1 though it is compatible with Spark 1.6.0 (with less JSON SQL functions). Prerequisites Refer to the following post to install Spark in Windows. ...
Problem When you follow Angular CLI installation guide in Windows, you may encounter the following error: ng is not recognized as an internal or external command The resolutions are available in the following link: ...
local_offer hadoop local_offer linux local_offer WSL
In my previous post , I showed how to configure a single node Hadoop instance on Windows 10. The steps are not too difficult to follow if you have Java programming backgr...
local_offer pyspark local_offer spark-2-x local_offer teradata local_offer SQL Server
In my previous article about Connect to SQL Server in Spark (PySpark) , I mentioned the ways t...
local_offer entity-framework local_offer asp.net core local_offer Azure local_offer C#
In SQL Server or some other relational databases, it is a very common requirement to create covering index with columns included in index pages beside the index key columns. With Entity Framework Core, you can also easily generate covering indexes using purely C# code. Scenario For ...
"Welcome to Kontext" Email Notifications
From 2020-06-27, Kontext will send out one "Welcome to Kontext!" email notifications to users for the following scenarios: when users register as a local user successfully and email is activated. when the first time users log in with Google and Microsoft accounts to register as...
local_offer oauth local_offer kontext
From release 0.7.4, Kontext users can now easily log in/sign up with Google or Microsoft accounts. Log in with Google or Microsoft accounts To log in using your Google or Microsoft accounts, simply click Log in button on the top navigation bar. ...
Sign-in with Google Error - {"error": "invalid_client", "error_description": "Unauthorized" }
local_offer asp.net core local_offer asp.net core 3
Sign-in with social accounts like Google, Microsoft, Twitter and Facebook accounts are very commonly used in websites to allow website users to logon easily without registering an separate account. Issue summary During the implementation of Kontext Google sign-in function, I encoun...
local_offer HTML local_offer Javascript local_offer bootstrap
On Kontext, a full width mega dropdown menu is implemented using Bootstrap 4. If you'd like to implement similar menus, please follow these steps. Environment The following code snippets work with Bootstrap 4.4.1. It should also work with other 4.x versions but I didn't test i...
local_offer teradata local_offer python
Pandas is commonly used by Python users to perform data operations. In many scenarios, the results need to be saved to a storage like Teradata. This article shows you how to do that easily using JayDeBeApi or ...
Python: Load / Read Multiline CSV File
CSV is a common data format used in many applications. It's also a common task for data workers to read and parse CSV and then save it into another storage such as RDBMS (Teradata, SQL Server, MySQL). In my previous article ...
Truncate table in Teradata
local_offer teradata local_offer SQL
In SQL Server, we can use TRUNCATE statement to clear all the records in a table and it usually performs better compared with DELETE statements as no transaction log for each individual row deletion. The syntax looks like the following: TRUNCATE TABLE { database_name.schema_name.tab...
local_offer teradata local_offer python local_offer Java
Python JayDeBeApi module allows you to connect from Python to Teradata databases using Java JDBC drivers. In article Connect to Teradata database through Python , I showed ho...
local_offer hadoop local_offer hive local_offer Java
When I was configuring Hive 3.0.0 in Hadoop 3.2.1 environment, I encountered the following error: Exception in thread "main" java.lang.NoSuchMethodError: com.google.common.base.Preconditions.checkArgument(ZLjava/lang/String;Ljava/lang/Object;)V Ro...
Pandas Read from SQLite Database
local_offer pandas local_offer sqlite
In my previous posts, I showed how to use jaydebeapi or sqlite3 pack...
Azure DNS is now in Use on Kontext
local_offer Azure local_offer kontext
In the past few months, Kontext's DNS server was not very stable as it went offline several times accidentally. When the DNS server is down, our domain (kontext.tech) cannot be parsed successfully to the IP address of Azure App Service (the service that hosts this website); thus it became unreach...
local_offer Azure local_offer asp.net core local_offer dotnetcore
With cloud platforms like Azure, we can totally separate user content storage from web application storage to decouple components from each other and to make the application easy to scale and deploy. This article provides detailed information with code snippets about how to use Azure server-less product Blob Storage and App Service to enable horizontally scalable web application for users to upload files (BLOBs).
local_offer Azure local_offer SQL Server
When designing the architecture of Kontext platform, Azure SQL Database is chosen as the storage for relational data. TDE and other advanced security features are always enabled to protect the database. Backup plans are also employed to ensure I can always restore the database for as point of tim...
Python: Read Data from SQLite via JDBC
local_offer sqlite local_offer python local_offer Java
To read data from SQLite database in Python, you can use the built-in sqlite3 package . Another approach is to use SQLite JDBC driver via ...
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ML.NET is an open source and cross-platform machine learning framework. With ML.NET, you can create custom ML models using C# or F# without having to leave the .NET ecosystem. This column publish articles about ML.NET.
AspNetCore.XmlRpc - a XML Remote Procedure Call library for ASP.NET Core.
For more details about Docu, please visit:
