Tutorial by Examples: co

CREATE TABLE menagerie.bird ( bird_id INT NOT NULL AUTO_INCREMENT, species VARCHAR(300) DEFAULT NULL COMMENT 'You can include genus, but never subspecies.', INDEX idx_species (species) COMMENT 'We must search on species often.', PRIMARY KEY (bird_id) ) ENGINE=InnoDB COMMENT 'Thi...

The Java programming language (and its runtime) has undergone numerous changes since its release since its initial public release. These changes include: Changes in the Java programming language syntax and semantics Changes in the APIs provided by the Java standard class libraries. Changes in ...

Every Python statement in Vim should be prefixed with the :python command, to instruct Vim that the next command is not Vimscript but Python. To avoid typing this command on each line, when executing multi-line Python code, it is possible to instruct Vim to interpret the code between two marker exp...

You can organize the execution of your instrumented unit tests defining a Suite. /** * Runs all unit tests. */ @RunWith(Suite.class) @Suite.SuiteClasses({MyTest1.class , MyTest2.class, MyTest3.class}) public class AndroidTestSuite {} Then in AndroidStudio you can run...

The NSTimeInterval value of this property indicates the seconds from which the date picker in countdown-timer mode counts down. If the mode of the date picker is not CountDownTimer, this value is ignored. Maximum value is 86,399 seconds (23:59) let datePicker = UIDatePicker(frame: CGRect(x: 0, y: 0...

Cassandra will not require users to login using the default configuration. Instead password-less, anonymous logins are permitted for anyone able to connect to the native_transport_port. This behaviour can be changed by editing the cassandra.yaml config to use a different authenticator: # Allow anon...

By default each user will be able to access all data in Cassandra. You'll have to configuring a different authorizer in your cassandra.yaml to grant individual object permissions to your users. # Grant all permissions to all users # authorizer: AllowAllAuthorizer # Use object permissions manage...

Private Sub Get_Last_Used_Row_Index() Dim wS As Worksheet Set wS = ThisWorkbook.Sheets("Sheet1") Debug.Print LastCol_1(wS) Debug.Print LastCol_0(wS) End Sub You can choose between 2 options, regarding if you want to know if there is no data in the worksheet :...

appendToFile: Append single src, or multiple srcs from local file system to the destination file system. Also reads input from stdin and appends to destination file system. Keep the as - hdfs dfs -appendToFile [localfile1 localfile2 ..] [/HDFS/FILE/PATH..] cat: Copies source paths to stdout. ...

The command pattern encapsulates parameters to a method, current object state, and which method to call. It is useful to compartmentalize everything needed to call a method at a later time. It can be used to issue a "command" and decide later which piece of code to use to execute the comma...

The TextInputLayout has a character counter for an EditText defined within it. The counter will be rendered below the EditText. Just use the setCounterEnabled() and setCounterMaxLength methods: TextInputLayout til = (TextInputLayout) findViewById(R.id.username); til.setCounterEnabled(true); til...

The Java Collections Framework provides two related methods for all Collection objects: size() returns the number of entries in a Collection, and isEmpty() method returns true if (and only if) the Collection is empty. Both methods can be used to test for collection emptiness. For example: C...

Let's say you have a library that returns callbacks, for example the fs module in NodeJS: const fs = require("fs"); fs.readFile("/foo.txt", (err, data) => { if(err) throw err; console.log(data); }); We want to convert it to a promise returning API, with bluebird - ...

You can convert a single function with a callback argument to a Promise-returning version with Promise.promisify, so this: const fs = require("fs"); fs.readFile("foo.txt", (err, data) => { if(err) throw err; console.log(data); }); becomes: const promisify = requ...

In order to convert any callback API to promises assuming the promisify and promisifyAll version doesn't fit - you can use the promise constructor. Creating promises generally means specifying when they settle - that means when they move to the fulfilled (completed) or rejected (errored) phase to i...

On a 8 cores Linux machine using GCC version 4.4, the C codes can be compiled and run the following way: $ gcc -std=c99 -O3 -fopenmp loop.c -o loopc -lm $ OMP_NUM_THREADS=1 ./loopc Computing 1000000 cosines and summing them with 1 threads took 0.095832s $ OMP_NUM_THREADS=2 ./loopc Computing 100...

Let f(n) and g(n) be two functions defined on the set of the positive real numbers, c, c1, c2, n0 are positive real constants. Notationf(n) = O(g(n))f(n) = Ω(g(n))f(n) = Θ(g(n))f(n) = o(g(n))f(n) = ω(g(n))Formal definition∃ c > 0, ∃ n0 > 0 : ∀ n ≥ n0, 0 ≤ f(n) ≤ c g(n)∃ c > 0, ∃ n0 > 0 ...

One of the primary uses for this cv-qualifiers is const correctness. This is the practice of guaranteeing that only accesses that need to modify an object are able to modify the object, and that any (member or non-member) function that doesn't need to modify an object doesn't have write access to t...

Apart from primitives, the Explicit Layout structs (Unions) in C#, can also contain other Structs. As long as a field is a Value type and not a Reference, it can be contained in a Union: using System; using System.Runtime.InteropServices; // The struct needs to be annotated as "Explici...

When signing personal scripts or when testing code signing it can be useful to create a self-signed code signing certificate. 5.0 Beginning with PowerShell 5.0 you can generate a self-signed code signing certificate by using the New-SelfSignedCertificate-cmdlet: New-SelfSignedCertificate -Friendl...