SEARCH KEYWORD -- Data type


  JSON in JavaScript

When sending an AJAX request to the server, the response can have two formats : XMLHttpRequest.responseXML to access data with XML format and XMLHttpRequest.responseText to access data with string format. XML is the standard data transfer format, but one weakness is it's troublesome to parse and retrieve the data. JSON(JavaScript Object Notation) is a light weight data interchange format, we call it the JavaScript object representation. The advantage of using JSON as the data format is itself is...

   JSON,JavaScript     2013-05-04 23:25:57

  Go channel explained

In Go, a channel is a type of concurrent data structure that allows two or more goroutines (Go's term for lightweight threads) to communicate with each other. Channels provide a way for goroutines to send and receive values, and they are an essential part of Go's concurrency model. Here's a simple example that demonstrates how to use channels in Go: package main import ( "fmt" ) func main() { // Create a new channel with the `make` function ch := make(chan int) // Start a new ...

   GOLANG,CHANNEL     2022-12-10 22:24:26

  Create wireless hotspot on your smartphone

It's now very common that you may not get Internet connection in first few days when you move to a new place. And you may have some important things to handle or you may just want to connect to Internet and share with others your new place. If you have a smartphone which has enough mobile data package, then you are on the way to enjoy Internet. Today we will introduce how to create a wireless hotspot on your smartphone with Samsung Galaxy S3 i9300. Step 1 Go to Settings -> More Settings ->...

   Wireless hotspot, Smartphone, Samsung     2013-01-12 23:08:39

  Different ways to pass query parameters in EmberJS

In EmberJS, one could pass query parameters when retrieving resources with store.query() method. But what if there is a requirement that one wants to pass query parameters when calling store.findRecord()? Or there is a requirement that one wants to pass query parameters to a relationship when calling model.get('hasManyAttribute') in a RESTful style? In this post, we will explain how these can be achieved. In the store.query() case, one could easily pass the query parameters by passing ...

   RELATIONSHIP,EMBERJS,QUERY PARAMETERS     2018-05-18 10:47:56

  CASSANDRA data model

Cassandra is an open source distributed database, it combines dynamic key/value and column oriented feature of Bigtable. Features of Cassandra are: Flexible schema, no need to design schema first, it's very convenient to add or delete strings Support range search on keys High usability, extensible. The single node error will not affect the cluster. We can think Cassandra's data model as a 4 or 5 dimensional Hash. COLUMN Columns is the smallest data unit in Cassandra, it is a 3 dimensional data...

   Cassandra,database,sort     2013-06-08 22:07:40

  Why should we keep column as NOT NULL instead of NULL in MySQL?

Keep table column as NOT NULL instead of NULL except in some special cases. This statement is cited by many articles of MySQL optimization, but they don't say why we should do this. Here we discuss about this. First why are there many people using NULL when defining table? The reasons may be: NULL the the default when defining table, the rookies or people who don't want to have much troubles will keep this default setting Many people think NOT NULL will require more space Many people don't want...

   MySQL,NULL,reason     2012-10-27 03:21:27

  The Go Pointer Magic

Go is a language with the pointer type, by which we can Pass pointer into a function and update value in-place. Add methods to a struct as (* T) A, which is different from (T) A(). However, the pointer is type-safe in Go, meaning that there are such restrictions of the pointer. Different types of pointers are unconvertible. Pointer type cannot be used for calculation. Pointer types cannot be compared, either == nor !=. No mutual assignment between different pointer-...

   GOLANG,POINTER,UNSAFE     2021-10-03 02:18:57

  /dev/null and /dev/tty in Linux

In Linux, there are two special files /dev/null and /dev/tty. /dev/null will drop all the data written to it, i.e, when program writes data to this file, it means the program has completed the data write operation. But in  fact it does nothing, if you just want the status of a command but not the output of a command, this feature will be very useful. See below shell codes:     /> vi test_dev_null.sh        #!/bin/bash    if grep...

   Linux,/dev/null,/dev/tty     2013-03-04 02:23:23

  Jack Ma's interviews during Alibaba's IPO at NYSE

Alibaba has been listed on NYSE on 19 September. It becomes the largest IPO ever in the history of US stock exchange, larger than Facebook then the largest one. And after the trading closed on Friday, its share price closed at $93.89 per share, this makes it the second largest Internet company in the world following Google. Jack Ma, the founder of Alibaba, also becomes the richest person in China with a total wealth of $18.1 billion. He accepted interviews from different media during the IPO. Le...

   Alibaba,Interview,Jack Ma,IPO,Video     2014-09-20 20:09:27

  Which program is using USB device?

Sometimes when we want to plug out our USB device, but the operating system tells us we cannot plug it out since some other processes are using the USB device. How do we know which process is using our USB device. Here is a simple solution.First, go to Start->All programs->Accessories->System Tools->Resource Monitor. (as in Windows 7, for other Windows systems, you may similar program called Resource Monitor but may not in the same location as in Windows 7).Then, open Resource Monito...

   Windows.ISB device,Plugout problem,Solut     2011-07-22 09:20:13

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