Tutorial by Examples: en

EXIT statement

PERFORM VARYING counter FROM 1 BY 1 UNTIL counter > 10 IF debug-override THEN EXIT PERFORM IF counter = 5 THEN EXIT PERFORM CYCLE PERFORM some-miracle END-PERFORM

cobol • EXIT statement

index.html <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <meta http-equiv="Content-Security-Policy" content="default-src *; script-src 'self' 'unsafe-inline' 'unsafe-eval' *; style-src 'self' 'unsafe-inline' *"/> ...

ionic-framework • Device camera and photo library access from Ionic application

Null Object Java using enum

Given an interface: public interface Logger { void log(String message); } Rather than usage: public void doJob(Logger logger) { if (logger != null) { logger.log("[doJob]:Step 1"); } // ... if (logger != null) { logger.log("[doJob]:Step 2&q...

Design patterns • Null Object pattern

Pre/Post Increment/Decrement operators

In C, there are two unary operators - '++' and '--' that are very common source of confusion. The operator ++ is called the increment operator and the operator -- is called the decrement operator. Both of them can be used used in either prefix form or postfix form. The syntax for prefix form for ++ ...

C Language • Side Effects

Encryption by certificate

CREATE CERTIFICATE My_New_Cert FROM FILE = 'D:\Temp\CertTest\certificateDER.cer' GO Create the certificate SELECT EncryptByCert(Cert_ID('My_New_Cert'), 'This text will get encrypted') encryption_test Usually, you would encrypt with a symmetric key, that key would get encrypted by the asym...

Microsoft SQL Server • Encryption

Encryption of database

USE TDE CREATE DATABASE ENCRYPTION KEY WITH ALGORITHM = AES_256 ENCRYPTION BY SERVER CERTIFICATE My_New_Cert GO ALTER DATABASE TDE SET ENCRYPTION ON GO This uses 'Transparent Data Encryption' (TDE)

Microsoft SQL Server • Encryption

Encryption by symmetric key

-- Create the key and protect it with the cert CREATE SYMMETRIC KEY My_Sym_Key WITH ALGORITHM = AES_256 ENCRYPTION BY CERTIFICATE My_New_Cert; GO -- open the key OPEN SYMMETRIC KEY My_Sym_Key DECRYPTION BY CERTIFICATE My_New_Cert; -- Encrypt SELECT EncryptByKey(Key_GUID('SSN_Key_01'),...

Microsoft SQL Server • Encryption

Write your own generator-backed iterator

A common pattern in other languages is having a function that produces a "stream" of objects, and being able to use loop-code to loop over it. We can model this in C++ as template<class T> struct generator_iterator { using difference_type=std::ptrdiff_t; using value_type=T; ...

C++ • Iterators

Sensible defaults

SASS gives you the ability to omit any parameter except the ones you want to overwrite of course. Let's take again the default-box example: @mixin default-box ($color: red, $borderColor: blue) { color: $color; border: 1px solid $borderColor; clear: both; display: block; mar...

sass • Mixins

Finding "out-of-sequence" records using the LAG() function

Given these sample data: IDSTATUSSTATUS_TIMESTATUS_BY1ONE2016-09-28-19.47.52.501398USER_13ONE2016-09-28-19.47.52.501511USER_21THREE2016-09-28-19.47.52.501517USER_33TWO2016-09-28-19.47.52.501521USER_23THREE2016-09-28-19.47.52.501524USER_4 Items identified by ID values must move from STATUS 'ONE' to...

SQL • Window Functions

Optional arguments

SASS's optional arguments let you use a parameter only if you specify its value; otherwise, it will be ignored. Let's take an example of the following mixin: @mixin galerie-thumbnail ($img-height:14em, $img-width: null) { width: $img-width; height: $img-height; outline: 1px solid li...

sass • Mixins

Benefits of deferred execution - building queries

Deferred execution enables combining different operations to build the final query, before evaluating the values: var list = new List<int>() {1,1,2,3,5,8}; var query = list.Select(x => x + 1); If we execute the query at this point: foreach (var x in query) { Console.Write($"...

linq • Method execution modes - immediate, deferred streaming, deferred non-streaming

Benefits of deferred execution - querying current data

With deferred execution, if the data to be queried is changed, the query object uses the data at the time of execution, not at the time of definition. var data = new List<int>() {2, 4, 6, 8}; var query = data.Select(x => x * x); If we execute the query at this point with an immediate m...

linq • Method execution modes - immediate, deferred streaming, deferred non-streaming

Defining an enumerated type

An enumerated type is a type that can hold one of a finite list of possible values. In Julia, enumerated types are typically called "enum types". For instance, one could use enum types to describe the seven days of the week, the twelve months of the year, the four suits of a standard 52-ca...

Julia Language • Enums

Using symbols as lightweight enums

Although the @enum macro is quite useful for most use cases, it can be excessive in some use cases. Disadvantages of @enum include: It creates a new type It is a little harder to extend It comes with functionality such as conversion, enumeration, and comparison, which may be superfluous in some...

Julia Language • Enums

Finding all instances of an entity class

All instances (objects) of an entity class can be loaded from the underlying database table as follows (akin to retrieving all rows from the table): Iterable<Foo> foos = fooRepository.findAll(); The findAll method is provided by the CrudRepository interface. It returns an Iterable instead ...

spring-data-jpa • Repositories

Finding a particular instance of an entity class by the identifier

A particular instance of an entity class can be loaded as follows: Foo foo = fooRepository.findOne(id); The findOne method is provided by the CrudRepository interface. It expects an identifier that uniquely identifies an entity instance (for instance, a primary key in a database table). The Java...

spring-data-jpa • Repositories

Finding all instances of an entity class with an attribute matching a specified value

All instances of an entity class with one of the class attributes matching a specified value can be retrieved as follows: public interface FooRepository extends CrudRepository<Foo, Long> { List<Foo> findAllByName(String name); } Invoking the findAllByName method results in the JP...

spring-data-jpa • Repositories

General points about error handling

Prolog features exceptions, which are part of the Prolog ISO standard. An exception can be thrown with throw/1, and caught with catch/3. The ISO standard defines many cases in which errors must or may be thrown. The standardized exceptions are all of the form error(E,_), where E indicates the erro...

Prolog Language • Error handling and exceptions

Enable CLR on database

CLR procedures are not enabled by default. You need to run the following queries to enable CLR: sp_configure 'show advanced options', 1; GO RECONFIGURE; GO sp_configure 'clr enabled', 1; GO RECONFIGURE; GO In addition, if some CLR module need external access, you should set TRUSTWORTHY pr...

Microsoft SQL Server • Common Language Runtime Integration