nvarchar(max) vs nvarchar(N)
MS SQL Server предоставляет нам на выбор несколько типов данных для хранения строк. Самый популярный - nvarchar(N) (где 1 ≤ N ≤ 4000) или nvarchar(max), который позволяет хранить строковые данные в кодировке Юникод. При этом, часто прикладные разработчики переносят опыт использования типа string из языка приложения (C# или Java, например) в базы данных и не задумываясь выбирают тип nvarchar(max), позволяющий хранить строки размером до 2ГБ. Но базы данных хранят и работают с данными совершенно другим способом. В этой статье я расскажу и покажу на практике, к чему может приводить неоправданное использование типа nvarchar(max).
List initializer
We all used to type new List<int> { 1, 2, 3, 4 } or new int[] { 1, 2, 3, 4} to initialize collections with some values. It looks similar in syntax but differs in behavior, and you should be careful if you are concerned about performance.
Harmful collection transformations. Part 3: collections
Starting with string in the first post we continue to study examples with collection transformations and how they affect our applications.
Harmful collection transformations. Part 2: automatic diagnostics
The previous post contains code examples that can be simplified by removing ToArray() or ToCharArray() calls. And an interesting example with List<char> constructor. But we need to be very attentive to find such places in our code. It would be much safer to do it automatically. This post shows us about automatic compiler diagnostics that can detect issues.
Harmful collection transformations. Part 1: string to array of chars
An array - the simplest collection. It's just a memory block with elements of one type. Arrays are often used when we need to iterate a collection, to search elements or transform them. C# and .net evolved, many new collections were introduced, interfaces allowed to create generalized algorithms, LINQ simplified the work of programmers, but we continue to use arrays in inappropriate places and perform excess and sometimes harmful transformations. This post begins a series about collections, their features, performance and design. All posts will contain benchmarks, code examples, my opinion and recommendations.
I want to start with a string, some specific collection of .net.