Databend built in scalar function development guide

Original text: https://databend.rs/development/how-to-write-scalar-functions/What is a scalar function? ¶Scalar functions (sometimes referred to as user-defined functions / UDFs) return a single value for each record, rather than as a result SET, and can be used in most places in queries or SET statements, except for the FROM clause.One to ...

Posted by thankqwerty on Mon, 06 Dec 2021 15:53:24 -0800

Summary of error handling operators in Rust

1 Option and ResultOption < T > is used to indicate whether there is a value. When there is a value, it is Some(T); Otherwise, None.enum Option<T> { None, Some(T), }Result < T, E > is used to indicate whether an error has occurred. When no error has occurred, it is Ok(T); Otherwise, Err(E).enum Result<T, E> { ...

Posted by asolell on Sat, 04 Dec 2021 11:58:19 -0800

Using linked list to learn Rust: A Bad Stack

Books recommended by a good friend, take advantage of Thanksgiving holiday to learn! Original in here , you can find a lot of Chinese translations on the Internet. There are explanation videos on a certain station, but I haven't seen them very much, so it's hard to evaluate them. This note is some records and experience in my learning process. ...

Posted by mbrown on Wed, 24 Nov 2021 15:27:30 -0800

RUST learning diary lesson 21 - iterator

RUST learning diary lesson 21 - iterator 0x00 review and opening The study of functions is over for the time being. This lesson is about iterators. When explaining the for loop earlier, we used the index to traverse each element. If the index position is not required in the traversal process, it is recommended to use the iterator to trave ...

Posted by jigen7 on Sat, 20 Nov 2021 04:04:25 -0800

The Rust Programming Language - Chapter 10 generics, trait, and lifecycle - 10.1 generic data types

10 generics, trait, and lifecycle Every programming language has tools to deal with repetitive concepts efficiently, and Rust uses generics. Generics are alternatives to concrete types or other abstract types. We can express the properties of generics, such as how their behavior is associated with other types of generics, without knowing what ...

Posted by vh3r on Tue, 16 Nov 2021 17:02:13 -0800

[algorithm] sword finger Offer II 054. Sum of all values greater than or equal to nodes | 538 | 1038 (Multilingual Implementation)

Thank you very much for reading this article~ Welcome[ 👍 [like][ ⭐ Collection][ 📝 [comments]~ It's not hard to give up, but it must be cool to insist~ I hope all of us can make a little progress every day~ This paper consists of White hat of the second leader: https://le-yi.blog.csdn.net/ Blog originality~ Sword finger Offer II 054. ...

Posted by dthomas31uk on Sun, 07 Nov 2021 20:59:32 -0800

Use Rust to create the library and call it in exe.

Use Rust to create the library and call it in exe. When using cargo new to create a project, there are options for the project type: – bin: compile to executable– lib: compile to library file The default is – lib. In fact, the types of libraries that Rust can create are as follows: rlib: Rust library, which is the defa ...

Posted by Deserteye on Wed, 20 Oct 2021 22:36:28 -0700

coswasm - wasm contract learning

preface For reference projects, the following projects can be found in GitHub find cosmwasm: branch 0.13wasmd: branch v0.15.1cosmwasm-template: branch 0.13wasmvm: branch 0.13 Rust compilation Attention The win system deletes all unnecessary code for compilation, and the. cargo configuration file needs to be modified [build] rustflags = "- ...

Posted by newmember on Thu, 14 Oct 2021 20:19:34 -0700

Sparse and two-dimensional arrays

Two-dimensional arrays can store a lot of things, such as Go, Gobang, the whole board can be seen as a huge two-dimensional array, in which black and white chess can be represented by the number 1 or 2 in the array, blank space is generally represented by 0. But because the board is large, the corresponding two-dimensional array is also large, ...

Posted by RobM on Wed, 15 Sep 2021 13:21:12 -0700

java-fair lock-re-lockable-deadlock-interrupt (how to gracefully stop a thread)

1. Fair-Unfair 1.1 Ticket Selling Cases (Unfair) class Ticket { private int number = 50; private Lock lock = new ReentrantLock(); //The default is an unfair lock. If you want an average allocation, =--, to be fair, change the constructor parameter to true public void sale() { lock.lock(); try { ...

Posted by SuperCam on Mon, 13 Sep 2021 20:06:10 -0700