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Using the Story Board: Select the tab bar item from the corresponding view controller and go to the attributes inspector If you want a built-in icon and title, set the 'System Item' to the corresponding value. For a custom icon, add the required images to the assets folder and set the 'System It...

See this Q&A question if you don't know what race conditions are. The following code may be subject to race conditions : article = Article.objects.get(pk=69) article.views_count += 1 article.save() If views_count is equal to 1337, this will result in such query: UPDATE app_article SET vi...

Transactions can be used to make multiple changes to the database atomically. Any normal transaction follows this pattern: // You need a writable database to perform transactions final SQLiteDatabase database = openHelper.getWritableDatabase(); // This call starts a transaction database.beginT...

Orders Table CustomerIdProductIdQuantityPrice12510013220014150021450356700 To check for customers who have ordered both - ProductID 2 and 3, HAVING can be used select customerId from orders where productID in (2,3) group by customerId having count(distinct productID) = 2 Return value:...

You need to create a new local copy of the repository with the command git svn clone SVN_REPO_ROOT_URL [DEST_FOLDER_PATH] -T TRUNK_REPO_PATH -t TAGS_REPO_PATH -b BRANCHES_REPO_PATH If your SVN repository follows the standard layout (trunk, branches, tags folders) you can save some typing: git svn...

Go to File -> Settings -> Editor -> Colors & Fonts -> Android Logcat Change the colors as you need: Choose the appropriate color:

Some basic types and classes in Java are fundamentally mutable. For example, all array types are mutable, and so are classes like java.util.Data. This can be awkward in situations where an immutable type is mandated. One way to deal with this is to create an immutable wrapper for the mutable type...

An anonymous method can be assigned wherever a delegate is expected: Func<int, int> square = delegate (int x) { return x * x; } Lambda expressions can be used to express the same thing: Func<int, int> square = x => x * x; In either case, we can now invoke the method stored ins...

Func also supports Covariant & Contravariant // Simple hierarchy of classes. public class Person { } public class Employee : Person { } class Program { static Employee FindByTitle(String title) { // This is a stub for a method that returns // an employee that h...

This example demonstrates how to fetch the URI's of system ringtones (RingtoneManager.TYPE_RINGTONE): private List<Uri> loadLocalRingtonesUris() { List<Uri> alarms = new ArrayList<>(); try { RingtoneManager ringtoneMgr = new RingtoneManager(getActivi...

You can let I18n handle pluralization for you, just use count argument. You need to set up your locale file like this: # config/locales/en.yml en: online_users: one: "1 user is online" other: "%{count} users are online" And then use the key you just created by ...

Anonymous methods provide a technique to pass a code block as a delegate parameter. They are methods with a body, but no name. delegate int IntOp(int lhs, int rhs); class Program { static void Main(string[] args) { // C# 2.0 definition IntOp add = delegate(int lhs,...

Array.join(separator) can be used to output an array as a string, with a configurable separator. Default (separator = ","): ["a", "b", "c"].join() === "a,b,c" With a string separator: [1, 2, 3, 4].join(" + ") === "1 + 2 + 3 + 4&q...

import 'dart:convert'; void main() { var jsonString = """ { "cats": { "abysinnian": { "origin": "Burma", "behavior": &qu...

Add one common horizontal line for all categorical variables # sample data df <- data.frame(x=('A', 'B'), y = c(3, 4)) p1 <- ggplot(df, aes(x=x, y=y)) + geom_bar(position = "dodge", stat = 'identity') + theme_bw() p1 + geom_hline(aes(yintercept=5), colour=...

To convert decimal number to binary format use base 2 Int32 Number = 15; Console.WriteLine(Convert.ToString(Number, 2)); //OUTPUT : 1111 To convert decimal number to octal format use base 8 int Number = 15; Console.WriteLine(Convert.ToString(Number, 8)); //OUTPUT : 17 To conv...

Specially useful for has_and_belongs_to_many relation, you can manually create a join table using the create_table method. Suppose you have two models Tags and Proyects, and you'd like to associate them using a has_and_belongs_to_many relation. You need a join table to associate instances of both c...

Position configuration for the credits label. Supported properties are align, verticalAlign, x and y. Defaults to: credits: { position: { align: 'right', x: -10, verticalAlign: 'bottom', y: -5 } },

GetLastError returns a numerical error code. To obtain a descriptive error message (e.g., to display to a user), you can call FormatMessage: // This functions fills a caller-defined character buffer (pBuffer) // of max length (cchBufferLength) with the human-readable error message // for a Win32 ...

Object oriented style Connect to Server $conn = new mysqli("localhost","my_user","my_password"); Set the default database: $conn->select_db("my_db"); Connect to Database $conn = new mysqli("localhost","my_user","my_password&q...