diff options
Diffstat (limited to 'kdb+.html.markdown')
| -rw-r--r-- | kdb+.html.markdown | 35 |
1 files changed, 16 insertions, 19 deletions
diff --git a/kdb+.html.markdown b/kdb+.html.markdown index db842726..0573067d 100644 --- a/kdb+.html.markdown +++ b/kdb+.html.markdown @@ -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) |