understanding tools for analyzing data
When I was trying to solve Challenge#4, I was trying to remember the variables that contains string of all the alphabets such as “ABCDEFGHIJKLMNOPQRSTUVWXYZ”. After some digging, I remembered that it was .Q.A. The only reason I knew about it was because I had used it earlier at my job. If you are new to …
Continue reading “Listing alphabets and numbers using predefined variables”
Some time back, when I was still getting familiar with qsql, I went for an interview at an investment bank. I was interviewed by 4 different people for a total of 2 hours. 3 of the interviewers asked theoretical architecture related questions but the last one was all about writing code. The last interviewer gave …
In one of my previous posts, I discussed functional form of select, update, exec and delete. If you remember, the general form of a functional select is ?[t;c;b;a] where t is the table, c is for constraints, b for by clause and a for aggregation. Most of the time, you will see only these 4 …
In one of my previous posts, I talked about functional forms of select, exec, update and delete. I also briefly touched on the importance of functional queries and why you should get used to them as much as possible if you are serious about q. In this post, I will talk about functional forms of …
I am going to assume that you all know what is a fibonacci sequence (FS). If you don’t, you can read up about it here. In my last post, I talked about using the adverb over. In this post, I will show you how over can be used to generate FS. Main thing about FS is that you …
One of the first things I was told by my ex boss was to never use for/while loops unless it’s a matter of life and death. And he was dead serious. I had just taken two c++ classes in college so wasn’t sure how I would be able to replace for/while loops. They are easy …
I used to hate functional queries. Part of me still does. They are hard to write, look like gibberish and not as simple to understand as qsql queries. I can’t believe I am saying this but as you get more familiar with q, you start seeing their advantages and point of their existence. q is …
If you have spent some time working with kdb+, there is no doubt that you have had to use some sort of join in your query. Joins are essential to data analyzing. kdb+ query language is called qsql which, as you probably guessed by name, is based on popular query language, SQL. I don’t have …
Real-time databases are easy to understand as everything is happening in memory. Historical databases are a different story. Recently, I have been getting much more involved with hdbs at work and just the way they work is incredible and fascinating to me. If you are serious about kdb+, you should make sure to know how …
Continue reading “How data is saved in a historical database”
I was planning on writing a blog post on how to save data to disk from a q process but then realized that I need to first cover the enumeration process because any data you wish to write to disk must be enumerated if it has a sym column. If you try to save a table …