mongoq

About

A C shared lib along with associated q functions to allow push/pull access to mongoDB from within kdb+

Installation

• Install the mongo c driver libraries | repo | instructions
• Clone the mongoq git repo
• Compile shared object using platform specific instructions below

Linux (64 bit)

gcc -o mongoq.so mongoq.c $(pkg-config --cflags --libs libmongoc-1.0) -I./ -shared -fPIC

Windows

CL /DWIN32 /I C:\usr\include\libbson-1.0 /I C:\usr\include\libmongoc-1.0 /LIBPATH C:\usr\lib\bson-1.0.lib /LIBPATH C:\usr\lib\mongoc-1.0.lib /LD mongoq.c q.lib /DEF mongoq.def

• copy the shared library file from the bin folder to the location of your q executable - e.g. $QHOME/l32
• copy mongo.q to $QHOME

Usage

Load and initialise library

This assumes there is a MongoDB server running on the local machine on the standard port - amend the connection details as required for your MongoDB setup

\l mongo.q
.mg.init[`localhost;27017;`kdb]

Insert data to MongoDB

q).mg.add[`test] `a`b`c!(1;`xyz;12t) / single record
00000000-54ef-b9bd-dfa8-32369e099741
q)r:.mg.add[`test] ([]time:3 4t;sym:`IBM`MSFT;price:23.4 56.7) / table

Query data from MongoDB

The '.mg.add' function returns a 16 byte UID type, which maps to the MongoDB ObjectID key of the inserted record. We can use these ids to retrieve data:

q).mg.find[`test;;()] r / all fields for id(s) r in table 'test'
time           sym    price
---------------------------
"03:00:00.000" "IBM"  23.4
"04:00:00.000" "MSFT" 56.7
q).mg.find[`test;;`sym`price] r / only sym & price fields
sym    price
------------
"IBM"  23.4
"MSFT" 56.7

Examples

• Comments database