Kx version 0.01 =============== This is Alpha code. It has had some reasonable testing but is really just experimental at the moment. I have run and tested this on Linux and MacOSX only. MacOSX is my major development platform (x86 only). INSTALLATION first get a copy of c.o from kx.com for your architecture make libkdb.a from c.o for easy linking ar -r libkdb.a c.o or libtool -static -o libkdb.a c.o perl Makefile.PL make make test # you must have a 'q' process running on port 2222 (q -p 2222) make install DEPENDENCIES This module requires these other modules and libraries: c.o from kx.com for your architecture q -p 2222 # for make test to actually do anything NAME Kx - Perl extension for Kdb+ http://kx.com SYNOPSIS use Kx; DESCRIPTION Create a wrapper around Kdb+ and Q in Perl using the C interface to Kdb+ EXPORT None by default. METHODS New $k = Kx->new(name=>'local22', host=>'localhost', port=>2222); Create a new K object. Set the connection paramaters to conect to 'host' and 'port' as specified. No connection is made to the server until you call $k->connect() $k = new K host=>'localhost', port=>2222; $k->connect(); # defaults to default; # picks up previous default connection to localhost port 2222 and # will use it as well. $k1 = new K; Environment There are a number of environment details you can glean from the Kdb+ server you are connected to. They are: my $arrayref = $k->tables; # The tables defined my $arrayref = $k->funcs; # The functions defined my $arrayref = $k->views; # The views defined my $arrayref = $k->variables; # The variables defined my $arrayref = $k->memory; # The memory details \w my $dir = $k->cwd; # The current working directory my $dir = $k->chdir($newdir); # Set the cwd my $num = $k->GMToffset; # Offset from GMT for times TABLES Create a new table in Kdb+ named mytab with 3 columns col1, col2 and col3. The keys will be on col1 and col3 This equates to the Q command # Q command q)mytab:([col1:;col3:] col2:) # The long winded Perl way $k->Tnew(name=>'mytab',keys=>['col1','col3'],cols=>['col2']); To add data use Tinsert(). Each row is added in the order defined above. This line adds 1 into col1, 2 into col3 and 3 into col2 as the keys are always defined before the other columns. $k->Tinsert('mytab',1,2,3); To do a select over a table use Tselect(). Tselect() takes a variable name as its first argument. The select will be executed and assigned to the variable you define. This way no data is passed from Kdb+ to the client until it is needed. $k->Tselect('a','select from mytab where col1>4'); To get the details of the stored selection my $numrows = $k->Tnumrows('a'); my $numcols = $k->Tnumcols('a'); You may have run a number of Tselects() and now wish to pull back the data. To do this use Tget() $k->Tget('table'); # table must be a table in the server To get access to random values in the returned table from Tget(). $val = $k->Tindex(row,col); To get the list of column names as Kdb+ knows them. my $header = $k->Theader(); print "@$header\n"; To get the meta data for a table as defined in KDB do this. my @meta = $k->Tmeta($table); foreach(@meta) { print "(name type) => (@$_)\n"; } To get a Perl reference to a column of data from the table (as K is column oriented) do the following: my $colref = $k->Tcol(0); # get the zeroth column print "Column 0 data is: @$colref\n"; Finally to delete or remove a table by name from the server: $k->Tdelete('table'); Here is a list of the complete table methods we have so far: $k->Tnew(name=>'thename',keys=>[],cols=>[]); $k->Tinsert('table',1,2,3); $k->Tbulkinsert('table',col1=>[],col2=>[],...); $k->Tget('select statement'); $scalar = $k->Tindex($row,$col); $arref = $k->Tcol(2); $arref = $k->Theader; $x = $k->Tnumrows; $y = $k->Tnumcols; $k->Tselect('table','select statement'); $k->Tsave('table','file'); $k->Tappend('table','file'); $k->Tload('table','file'); $k->Tdelete('table'); COMMANDS Execute the code on an already accessable Kdb+ server. The query is executed and the results are held in K structures in RAM. Example $return = $k->cmd('b:til 100'); The cmd() function will return a reference to an array if the Q command returns a list. It will return a simple scalar if the result is a scalar response from Q. It will return a hash reference if the return result from Q is either table/keyed table/dictionary. You need to know what you are doing so can know what the result is (or use Perl's ref()). If you have a Q script that you wish to run against the Kdb+ server you can use the do(file) method. Any error in your script that is caught will stop do(file) from proceeding. If you don't care when it is done then use dolater(file). Both do() and dolater() don't return anything useful. They just blindly execute each line of Q against the server. If you want to check each command and do stuff as a result then use cmd() and check the result. An example file name foo.txt holds the lines: t:([]a:();b:()) insert[`t](`a;10.70) insert[`t](`b;-5.6) insert[`t](`c;21.73) You can run that file by doing this: $k->do("foo.txt"); ATOMS and STRUCTURES To create Kdb+ atoms locally in RAM use the following calls. $k = new K; my $d; $d=$k->bool(0); # boolean $d=$k->byte(100); # char $d=$k->char(ord('a')); # char $d=$k->short(20); $d=$k->int(70); $d=$k->long(93939); $d=$k->real(20.44); # remember 20.44 may look close as a real $d=$k->float(20.44); # should look closer to 20.44 as a float $d=$k->sym('mysymbol'); # A Kdb+ symbol $d=$k->date(2007,4,22); # integer encoded date year, month, day $d=$k->dt(time()); # Kdb+ datetime from epoch $d=$k->tm(100); # Time type in milliseconds These allow for fine grained control over the 'type' of K object you want. If you don't mind particularly about the type conversions then you can use perl2K() like this. $d = $k->perl2K('mysymbol'); $d = $k->perl2K([qw/this will be a K list of symbols/]); $d = $k->perl2K({this => 1, that => 2, 'is a' => 'dict'}); To get a Perl value back from a Kdb+ atom try this; my $val = $d->val(); To get the internal value back from a Kdb+ atom try this; my $val = $k->kval; # used in $x->cmd('func',$val) As a further comment on the date() method. When you look at the value Example: # Simple create my $k = new K; my $bool = $k->bool(0); print "My boolean in K is ",$bool->val,"\n"; LISTS These list functions create in memory local lists outside of any 'q' running process. These will allow you to create very large simple lists without blowing out all your memory. To create a simple Kdb+ list of a single type use the listof() function. The type of the list is passed in as the second aregument and can be one of: Kx::KC() char Kx::KD() date yyyy mm dd Kx::KE() real Kx::KF() float Kx::KG() byte Kx::KH() short Kx::KI() integer Kx::KJ() long Kx::KM() month Kx::KS() symbol (internalised string) Kx::KT() time Kx::KU() minute Kx::KV() second Kx::KZ() datetime epoch seconds Example simple lists: my $k = new K; my $list = $k->listof(20,Kx::KS()); # List of 20 symbols for( my $i=0; $i < 20; $i++) { $list->at($i,"symbol$i"); } # To get at the 4th element my $sym = $list->at(3); # symbol3 my $perl_list = $list->list; print "Symbols are @$perl_list\n"; # dates $d = $k->listof(20,Kx::KD()); for( my $i=0; $i < 20; $i++) { $d->at($i,2007,4,$i+1); # 20070401 -> 20070421 } # Add an extra date to the end of the list my $day = $k->date(2007,4,30); $d->joinatom($day->kval); Kx::LIST You may wish to tie a Perl array to a Kdb+ variable. Well, you can do that as well. Try something like this: use K; my %config = ( host=>"localhost", port=>2222, type=>'symbol', list=>'d', create=>1 ); tie(@a, 'Kx::LIST', %config); # push lost of stuff on an array my @array = (qw/aaaa bbbbb ccccc ddddddddd e f j h i j k l/) x 30000 ; push(@a,@array); push(@a,@array); push(@a,@array); print "\@a has ", scalar(@a)," elements\n"; # Store $a[3] = "Help me"; print "Elementt 3 is ",$a[3],"\n"; All the functions defined in perltie for lists are included. Note: 'type' is a Kdb+ type as defined in Types below - it is the type for the array. Only simple types are allowed at the moment. Kx::HASH You may wish to tie a Perl hash to a Kdb+ variable. Well, you can do that as well. Try something like this: use K; my %config = ( host=>"localhost", port=>2222, ktype=>'symbol', vtype=>'int', dict=>'x', create=>1 ); tie(%x, 'Kx::HASH', %config); print "Size of hash x is :". scalar %x ."\n"; for(0..5) { $x{"a$_"} = $_; } %y = %x; for(0..5) { print $y{"a$_"}," " if exists $y{"a$_"}; } print "\n"; while(($k,$v) = each %x) { print "Key=>$k is $v\n"; } untie(%x); All the functions defined in perltie for hashs are included. Note: ktype is a Kdb+ type as defined in Types below - it is the 'key' type for the hash. vtype is also defined in Types - it is the value type. Only simple types are allowed at the moment. SEE ALSO http://kx.com http://code.kx.com See the test code under the 't' directory of this module for more details on how to call each method. AUTHOR Mark Pfeiffer, COPYRIGHT AND LICENSE Copyright (C) 2007 by Mark Pfeiffer This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.6 or, at your option, any later version of Perl 5 you may have available.