Tutorial by Examples: table

MySQL's DELETE statement can use the JOIN construct, allowing also to specify which tables to delete from. This is useful to avoid nested queries. Given the schema: create table people ( id int primary key, name varchar(100) not null, gender char(1) not null ); insert people (id,na...

Sometimes a column should show different content than just the toString value of the cell item. In this case the TableCells created by the cellFactory of the TableColumn is customized to change the layout based on the item. Important Note: TableView only creates the TableCells that are shown in the...

By default, the implicit operator() of a lambda is const. This disallows performing non-const operations on the lambda. In order to allow modifying members, a lambda may be marked mutable, which makes the implicit operator() non-const: int a = 0; auto bad_counter = [a] { return a++; // er...

If you are looking to run a file, such as an executable, use child_process.execFile. Instead of spawning a shell like child_process.exec would, it will directly create a new process, which is slightly more efficient than running a command. The function can be used like so: const execFile = require(...

A section containing data arranged in rows and columns. The table role is intended for tabular containers which are not interactive. <table role="table"> <thead> <!-- etc --> </thead> <tbody> <!-- etc --> </tbody> </table...

If you want to see the schema information of your table, you can use one of the following: SHOW CREATE TABLE child; -- Option 1 CREATE TABLE `child` ( `id` int(11) NOT NULL AUTO_INCREMENT, `fullName` varchar(100) NOT NULL, `myParent` int(11) NOT NULL, PRIMARY KEY (`id`), KEY `momm...

// You need a writable database to update a row final SQLiteDatabase database = openHelper.getWritableDatabase(); // Create a ContentValues instance which contains the up to date data for each column // Unlike when inserting data you need to specify the value for the PRIMARY KEY column as well ...

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 immutable object is an object whose state cannot be changed. An immutable class is a class whose instances are immutable by design, and implementation. The Java class which is most commonly presented as an example of immutability is java.lang.String. The following is a stereotypical example: ...

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...

// RawRepresentable has an associatedType RawValue. // For this struct, we will make the compiler infer the type // by implementing the rawValue variable with a type of String // // Compiler infers RawValue = String without needing typealias // struct NotificationName: RawRepresentable { ...

This example uses a search controller to filter the cells in a table view controller. The search bar is placed inside the header view of the table view. The table view content is offset with the same height as the search bar so that the search bar is hidden at first. Upon scrolling up past the top e...

CREATE DATABASE stackoverflow; USE stackoverflow; Create table stack( id_user int NOT NULL, username varchar(30) NOT NULL, password varchar(30) NOT NULL ); ALTER TABLE stack ADD COLUMN submit date NOT NULL; -- add new column ALTER TABLE stack DROP COLUMN submit; -- drop col...

data.table extends reshape2's melt & dcast functions (Reference: Efficient reshaping using data.tables) library(data.table) ## generate some data dt <- data.table( name = rep(c("firstName", "secondName"), each=4), numbers = rep(1:4, 2), value = rnorm(8) ) ...

DESCRIBE and EXPLAIN are synonyms. DESCRIBE on a tablename returns the definition of the columns. DESCRIBE tablename; Exmple Result: COLUMN_NAME COLUMN_TYPE IS_NULLABLE COLUMN_KEY COLUMN_DEFAULT EXTRA id int(11) NO PRI 0 ...

In this example, we have a Countries table. A table for countries has many uses, especially in Financial applications involving currencies and exchange rates. Live example: SQL fiddle Some Market data software applications like Bloomberg and Reuters require you to give their API either a 2 or 3 ch...

CREATE TABLE table_name ( id INT NOT NULL AUTO_INCREMENT, json_col JSON, PRIMARY KEY(id) );

This is useful to see if there are any non-printable characters, or non-ASCII characters. e.g. If you have copy-pasted the code from web, you may have quotes like ” instead of standard ". $ cat -v file.txt $ cat -vE file.txt # Useful in detecting trailing spaces. e.g. $ echo '” ' | c...

+ dictionaryWithCapacity: Creates and returns a mutable dictionary, initially giving it enough allocated memory to hold a given number of entries. NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithCapacity:1]; NSLog(@"%@",dict); - init Initializes a newly allocated mut...

- removeObjectForKey: Removes a given key and its associated value from the dictionary. NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithDictionary:@{@"key1":@"Easy",@"key2": @"Tutorials"}]; [dict removeObjectForKey:@"key1"]; NSLog...