Tutorial by Examples: ase

Use ORDER BY with TOP to return the top x rows based on a column's value

In this example, we can use GROUP BY not only determined the sort of the rows returned, but also what rows are returned, since we're using TOP to limit the result set. Let's say we want to return the top 5 highest reputation users from an unnamed popular Q&A site. Without ORDER BY This query ...

SQL • ORDER BY

Comparsion: strcmp(), strncmp(), strcasecmp(), strncasecmp()

The strcase*-functions are not Standard C, but a POSIX extension. The strcmp function lexicographically compare two null-terminated character arrays. The functions return a negative value if the first argument appears before the second in lexicographical order, zero if they compare equal, or positi...

C Language • Strings

Modifying the case of alphabetic characters

4.0 To uppercase $ v="hello" # Just the first character $ printf '%s\n' "${v^}" Hello # All characters $ printf '%s\n' "${v^^}" HELLO # Alternative $ v="hello world" $ declare -u string="$v" $ echo "$string" HELLO WORLD To l...

Bash • Bash Parameter Expansion

Create a database snapshot

A database snapshot is a read-only, static view of a SQL Server database (the source database). It is similar to backup, but it is available as any other database so client can query snapshot database. CREATE DATABASE MyDatabase_morning -- name of the snapshot ON ( NAME=MyDatabase_data, -- l...

Microsoft SQL Server • Database Snapshots

Restore a database snapshot

If data in a source database becomes damaged or some wrong data is written into database, in some cases, reverting the database to a database snapshot that predates the damage might be an appropriate alternative to restoring the database from a backup. RESTORE DATABASE MYDATABASE FROM DATABASE_SNAP...

Microsoft SQL Server • Database Snapshots

Count the Number of Tables in a Database

This query will return the number of tables in the specified database. USE YourDatabaseName SELECT COUNT(*) from INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE = 'BASE TABLE' Following is another way this can be done for all user tables with SQL Server 2008+. The reference is here. SELECT COUNT(...

Microsoft SQL Server • Retrieve information about the database

How streams work - filter, upper case, then sort a list

// Java: List<String> myList = Arrays.asList("a1", "a2", "b1", "c2", "c1"); myList.stream() .filter(s -> s.startsWith("c")) .map(String::toUpperCase) .sorted() .forEach(System.out::println); // C1 ...

Kotlin • Java 8 Stream Equivalents

Templating in Class Based Views

You can pass data to a template in a custom variable. In your views.py: from django.views.generic import TemplateView from MyProject.myapp.models import Item class ItemView(TemplateView): template_name = "item.html" def items(self): """ Get all Ite...

Django • Templating

Advanced Aliases

Git lets you use non-git commands and full sh shell syntax in your aliases if you prefix them with !. In your ~/.gitconfig file: [alias] temp = !git add -A && git commit -m "Temp" The fact that full shell syntax is available in these prefixed aliases also means you can us...

Git • Aliases

Running Scollector as a service

On Windows you can install Scollector as a service using the -winsvc="install" flag. On Mac and Linux you must manually create a service or init script. For example here is a basic systemd unit file: #Scollector unit file saved to /etc/systemd/system/scollector.service [Unit] Descriptio...

Bosun • Scollector: Overview

Base Document Language

It’s a good practice to declare the primary language of the document in the html element: <html lang="en"> If no other lang attribute is specified in the document, it means that everything (i.e., element content and attribute text values) is in that language. If the document con...

HTML • Content Languages

Templating in Function Based Views

You can use a template in a function based view as follows: from django.shortcuts import render def view(request): return render(request, "template.html") If you want to use template variables, you can do so as follows: from django.shortcuts import render def view(request):...

Django • Templating

Linear regression on the mtcars dataset

The built-in mtcars data frame contains information about 32 cars, including their weight, fuel efficiency (in miles-per-gallon), speed, etc. (To find out more about the dataset, use help(mtcars)). If we are interested in the relationship between fuel efficiency (mpg) and weight (wt) we may start p...

R Language • Linear Models (Regression)

Get the list of all databases on a server

Method 1: Below query will be applicable for SQL Server 2000+ version (Contains 12 columns) SELECT * FROM dbo.sysdatabases Method 2: Below query extract information about databases with more informations (ex: State, Isolation, recovery model etc.) Note: This is a catalog view and will be availa...

Microsoft SQL Server • Retrieve information about the database

Generic selection based on multiple arguments

If a selection on multiple arguments for a type generic expression is wanted, and all types in question are arithmetic types, an easy way to avoid nested _Generic expressions is to use addition of the parameters in the controlling expression: int max_int(int, int); unsigned max_unsigned(unsigned, ...

C Language • Generic selection

Validate unique value from database in Yii2

Few people have issue regarding error message not displaying if existing value is being entered in textbox. So, For Example I'm not allowing user to enter existing email. signup.php (Page where you wanted to sign up new user without existing email id) Remove use yii\bootstrap\ActiveForm; (if p...

yii2 • Validation

Validating Unique Value From Database : Unique Validation

Some people have issues regarding error messages not being displayed if an existing value is being entered. For example I'm not allowing a user signup with an existing email. View <?php ...................... <?= $form->field($modelUser, 'email')->textInput(['class'=&gt...

yii2 • Validation

Extension methods dispatch based on static type

The static (compile-time) type is used rather than the dynamic (run-time type) to match parameters. public class Base { public virtual string GetName() { return "Base"; } } public class Derived : Base { public override string GetName() { ...

C# Language • Extension Methods

Create a new Rails app with your choice of database and including the RSpec Testing Tool

Rails uses sqlite3 as the default database, but you can generate a new rails application with a database of your choice. Just add the -d option followed by the name of the database. $ rails new MyApp -T -d postgresql This is a (non-exhaustive) list of available database options: mysql oracle...

Ruby on Rails • Getting started with Ruby on Rails

Case manipulation

"string".upcase # => "STRING" "STRING".downcase # => "string" "String".swapcase # => "sTRING" "string".capitalize # => "String" These four methods do not modify the original receiver. For exampl...

Ruby Language • Strings