Tutorial by Examples: ed

The first to thing to have: a model that contains a has_many relation with another model. class Project < ApplicationRecord has_many :todos end class Todo < ApplicationRecord belongs_to :project end In ProjectsController: class ProjectsController < ApplicationController d...

It is a bad practice to block on async calls as it can cause deadlocks in environments that have a synchronization context. The best practice is to use async/await "all the way down." For example, the following Windows Forms code causes a deadlock: private async Task<bool> TryThis()...

//Using File.WriteAllBytes using (ExcelPackage excelPackage = new ExcelPackage()) { //create a new Worksheet ExcelWorksheet worksheet = excelPackage.Workbook.Worksheets.Add("Sheet 1"); //add some text to cell A1 worksheet.Cells["A1"].Value = "My fourt...

Ifconfig List all the interfaces available on the machine $ ifconfig -a List the details of a specific interface Syntax: $ ifconfig <interface> Example: $ ifconfig eth0 eth0 Link encap:Ethernet HWaddr xx:xx:xx:xx:xx:xx inet addr:x.x.x.x Bcast:x.x.x.x Mask:x.x.x.x ...

File: /etc/resolv.conf contains a list of DNS servers for domain name resolution Sample contents of the file: nameserver 8.8.8.8 # IP address of the primary name server nameserver 8.8.4.4 # IP address of the secondary name server In case internal DNS server you can validate if this server reso...

This should always be your initial fix. A good policy is to decompile the database before each release. Create a decompile shortcut. This loads the database with a "/decompile" switch. Right Click your Database File. Select Copy Right Click in the explorer window and select &quot...

This is a lot of work, so do this as a last resort after exhausting all other options. You only need to do this if the problem is occurring for different users, on different machines. If it isn't occurring for all users, then most likely it is not a corrupt database container. Similar to the steps...

Appearance: "Paamayim Nekudotayim" means "double colon" in Hebrew; thus this error refers to the inappropriate use of the double colon operator (::). The error is typically caused by an attempt to call a static method that is, in fact, not static. Possible Solution: $classname...

Detailed instructions on getting amazon-cloudformation set up or installed. Amazon cloud formation templates can be launched in three ways. AWS Console. AWS CLI. AWS SDK available in Java, Ruby etc.. AWS CLI is one of the most intuitive CLI available. The commands are simple to ...

This example illustrates a concept to perform reduction or gathering using std::vector and OpenMP. Supposed we have a scenario where we want multiple threads to help us generate a bunch of stuff, int is used here for simplicity and can be replaced with other data types. This is particularly useful...

//create a new ExcelPackage using (ExcelPackage excelPackage = new ExcelPackage()) { //the query or stored procedure name for the database string sqlQuery = "SELECT * FROM myTable"; //create a datatable DataTable dataTable = loadExternalDataSet(sqlQuery); //c...

Dim oDic Set oDic = CreateObject("Scripting.Dictionary") oDic.Add "US", "United States of America" oDic.Add "UK", "United Kingdom"

There are a lot of good video tutorials for the AngularJS framework on egghead.io https://egghead.io/courses/angularjs-app-from-scratch-getting-started https://egghead.io/courses/angularjs-application-architecture https://egghead.io/courses/angular-material-introduction https://egghead.io/co...

Create a sample table on a sample database CREATE TABLE [dbo].[Table_1]( [Id] [int] IDENTITY(1,1) NOT NULL, [title] [varchar](50) NULL, CONSTRAINT [PK_Table_1] PRIMARY KEY CLUSTERED ( [Id] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_...

set oDic = CreateObject("Scripting.Dictionary") oDic.add "USA", "United States of America" oDic.add "UK", "United Kingdom" oDic.add "CAN", "Canada" For Each obj in oDic.Items Msgbox obj Next Set oDic = Nothing *Out...

iOS 10 Now Requires User Permission to Access Media Library, Photos, Camera and other Hardware like these. The solution for this is to add their keys into info.plist with description for user that how we are using their data , iOS already required permissions to access microphone, camera, and m...

From Xcode menu open: Product > Scheme > Edit Scheme. On your Environment Variables set OS_ACTIVITY_MODE = disable

SELECT item.item_id, uses.category, /* nonstandard */ COUNT(*) number_of_uses FROM item JOIN uses ON item.item_id, uses.item_id GROUP BY item.item_id will show the rows in a table called item, and show the count of related rows in a table called uses. It will also show the va...

A very easy way to connect to an ORACLE database is by using oracledb module. This module handles the connection between your Node.js app and Oracle server. You can install it like any other module: npm install oracledb Now you have to create an ORACLE connection, which you can later query. co...

#import <Foundation/Foundation.h> int main() { NSLog(@"File :%s\n", __FILE__ ); NSLog(@"Date :%s\n", __DATE__ ); NSLog(@"Time :%s\n", __TIME__ ); NSLog(@"Line :%d\n", __LINE__ ); NSLog(@"ANSI :%d\n", __STDC__ ); ...