programming

Internet, Software Engineers and Problem Solving Ability

I have been doing programming and software engineering since 1998. And professionally since 2003. Over the last 20 years or so we the software engineers have become incredibly productive because of advances in techniques and tooling. What used to take 5 days now can be accomplished in a day or two. Better tools are available for free thanks to the open source movement. Thanks to the proliferation of the internet these tools are now just a click away.

Dockerfile for dotnet core worker process

In this article we will talk about creating a dotnet core worker process and we will run it in a docker container. This article is divided into two parts, in the first part we will create a simple worker process and in the second part we will write the Dockerfile to containerise it. If you already know about creating workers in dotnetcore feel free to skip the first part. Creating the dotnet core worker processs From your favourite shell, execute the following commands:

How to pass data between screens in Flutter

In this article we will talk about three methods by which data can be passed from one screen to another in flutter. 1. Using constructors This is a very well known technique that is used in other languages as well. What we do is we pass the needed data in the constructor when we instatiate the target class. Lets assume that we have a screen say ConstructorScreen. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 class ConstructorScreen extends StatelessWidget { String message; ConstructorScreen(String m){ this.

How to authenticate and login users in Flutter from a REST Api

Suggested laptop for programming Lenovo IdeaPad S145 AMD Ryzen 5 15.6" FHD Thin and Light Laptop (8GB/512GB SSD/Windows10/Office/Platinum Grey/1.85Kg) Buy on Amazon Introduction In this article we will discuss how to use a REST api backend to authenticate users from a Flutter app. We will build a very basic nodejs REST api backend. If you already have a backend then you can use that also. And then we will be building a basic Flutter app to connect to this backend and login to the app.

How to Use Textwatcher in Android

The Android framework provides the EditText interface element to allow the entry and editing of text. There are some use cases where one might need to detect text changes as they are typed in the EditText and react accordingly. One use case could be showing auto suggest values. The TextWatcher interface can be used for listening in for changes in text in an EditText. This interface has three abstract methods - afterTextChanged(Editable s) beforeTextChanged(CharSequence s, int start, int count, int after) onTextChanged(CharSequence s, int start, int before, int count) Wiring the TextWatcher to the EditText If you take a look at EditText’s documentation, you won’t see any obvious way to wire the TextWatcher to it.

How to Use Datepicker in Flutter

Its not too tough, really. We are going to create a very simple project to demonstrate the use of the datepicker, in particular the material datepicker. If you prefer the video version, you can watch it below. Suggested laptop for programming Lenovo IdeaPad S145 AMD Ryzen 5 15.6" FHD Thin and Light Laptop (8GB/512GB SSD/Windows10/Office/Platinum Grey/1.85Kg) Buy on Amazon Suggested readings Flutter for Beginners: An introductory guide to building cross-platform mobile applications with Flutter and Dart 2 Beginning App Development with Flutter: Create Cross-Platform Mobile Apps Lets see how its going to look.

Writing A On Update Trigger in Postgresql

The previous [article] ( /posts/writing-a-on-delete-trigger-in-postgresql/) was about deletion trigger. This article is about update triggers. I had two tables what_did_you_eat and what_was_the_type. On insertion into what_did_you_eat, the what_type column was populated with the food type. Now, if I update the value in what column of a row from what_did_you_eat, I would want the corresponding row in what_was_the_type table to be updated too. For example, if we have the following data:

Writing a On Delete Trigger in Postgresql

The previous [article] ( /posts/writing-a-on-insert-trigger-in-postgresql/) was about insertion trigger. I had two tables what_did_you_eat and what_was_the_type. On insertion into what_did_you_eat, the what_type column was populated with the food type. Now, if I delete a row from what_did_you_eat, I would not want a row to remain in what_was_the_type to refer to a non existing row in the what_did_you_eat table. To handle this, I will use the delete trigger. Like before we first write the trigger function.

Writing A On Insert Trigger In Postgresql

Here is a simple example of a on insert postgresql trigger. I have a table called what_did_you_eat. It has the following structure - what will contain what was eaten. I have another table called what_was_the_type with the following structure - I want to store the type of food that was eaten in what_type column. And I want to do this to happen on insert into the what_did_you_eat table. So, off we go to write a trigger.

How To Parse Json In A Stored Procedure In Postgresql

Say we have a table called person with the following structure --------------------------- column| datatype --------------------------- _id | autonumber name | text age | integer --------------------------- We want to insert multiple records into the table using a stored procedure. If we have a stored procedure with say two input variables name and age, then it will take multiple calls. We can do this using a single call if we use a json input and using the json_to_recordset function.