iskm/learnxinyminutes-docs
1
0
Fork 0
mirror of https://github.com/adambard/learnxinyminutes-docs.git synced 2024-12-23 17:41:41 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

[kdb+/en] highlight and update links

Browse Source
This commit is contained in:
Boris Verkhovskiy 2024-04-19 02:19:54 -07:00
parent fbd84cf623
commit ecd16aedf9
1 changed files with 16 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
kdb+.html.markdown
View File

@ -11,24 +11,22 @@ and released by Kx systems in 2003. q is a descendant of APL and as such is
very terse and a little strange looking for anyone from a "C heritage" language
background. Its expressiveness and vector oriented nature make it well suited
to performing complex calculations on large amounts of data (while also
encouraging some amount of [code
golf](https://en.wikipedia.org/wiki/Code_golf)). The fundamental structure in
the language is not the object but instead the list, and tables are built as
collections of lists. This means - unlike most traditional RDBMS systems -
tables are column oriented. The language has both an in-memory and on-disk
database built in, giving a large amount of flexibility. kdb+ is most widely
used in the world of finance to store, analyze, process and retrieve large
encouraging some amount of [code golf](https://en.wikipedia.org/wiki/Code_golf)).
The fundamental structure in the language is not the object but instead the list,
and tables are built as collections of lists. This means - unlike most traditional
RDBMS systems - tables are column oriented. The language has both an in-memory
and on-disk database built in, giving a large amount of flexibility. kdb+ is most
widely used in the world of finance to store, analyze, process and retrieve large
time-series data sets.
The terms *q* and *kdb+* are usually used interchangeably, as the two are not
separable so this distinction is not really useful.
All Feedback welcome! You can reach me at matt.doherty@aquaq.co.uk, or Jonny
at jonny.press@aquaq.co.uk
To learn more about kdb+ you can join the
[KX Community forums](https://learninghub.kx.com/forums/) or
the [TorQ kdb+](https://groups.google.com/forum/#!forum/kdbtorq) group.
To learn more about kdb+ you can join the [Personal kdb+](https://groups.google.com/forum/#!forum/personal-kdbplus) or [TorQ kdb+](https://groups.google.com/forum/#!forum/kdbtorq) group.
```
```q
/ Single line comments start with a forward-slash
/ These can also be used in-line, so long as at least one whitespace character
/ separates it from text to the left
@ -47,7 +45,7 @@ To learn more about kdb+ you can join the [Personal kdb+](https://groups.google.
/ We have integers, which are 8 byte by default
3 / => 3
/ And floats, also 8 byte as standard. Trailing f distinguishes from int
/ And floats, also 8 byte as standard. Trailing f distinguishes from int
3.0 / => 3f
/ 4 byte numerical types can also be specified with trailing chars
@ -656,7 +654,7 @@ t lj le
/ => Polly 52 160 f 85
/ => John 25 178 m 78
/ aj is an asof join. This is not a standard SQL join, and can be very powerful
/ aj is an asof join. This is not a standard SQL join, and can be very powerful
/ The canonical example of this is joining financial trades and quotes tables
trades:([]time:10:01:01 10:01:03 10:01:04;sym:`msft`ibm`ge;qty:100 200 150)
quotes:([]time:10:01:00 10:01:01 10:01:01 10:01:03;
@ -700,7 +698,7 @@ first each (1 2 3;4 5 6;7 8 9)
/ The true alternatives to loops in q are the adverbs scan (\) and over (/)
/ their behaviour differs based on the number of arguments the function they
/ are modifying receives. Here I'll summarise some of the most useful cases
/ are modifying receives. Here I'll summarise some of the most useful cases
/ a single argument function modified by scan given 2 args behaves like "do"
{x * 2}\[5;1] / => 1 2 4 8 16 32 (i.e. multiply by 2, 5 times)
{x * 2}/[5;1] / => 32 (using over only the final result is shown)
@ -761,10 +759,10 @@ select from splayed / (the columns are read from disk on request)
////// Frameworks //////
/ kdb+ is typically used for data capture and analysis.
/ This involves using an architecture with multiple processes
/ working together. kdb+ frameworks are available to streamline the setup
/ working together. kdb+ frameworks are available to streamline the setup
/ and configuration of this architecture and add additional functionality
/ such as disaster recovery, logging, access, load balancing etc.
/ https://github.com/AquaQAnalytics/TorQ
/ https://github.com/DataIntellectTech/TorQ
```
## Want to know more?
@ -772,5 +770,4 @@ select from splayed / (the columns are read from disk on request)
* [*q for mortals* q language tutorial](http://code.kx.com/q4m3/)
* [*Introduction to Kdb+* on disk data tutorial](http://code.kx.com/q4m3/14_Introduction_to_Kdb+/)
* [q language reference](https://code.kx.com/q/ref/)
* [Online training courses](http://training.aquaq.co.uk/)
* [TorQ production framework](https://github.com/AquaQAnalytics/TorQ)
* [TorQ production framework](https://github.com/DataIntellectTech/TorQ)