Request data from Kx Systems, Inc. kdb+ databases
d = fetch(k,ksql)
d = fetch(k,ksql,p1)
d = fetch(k,ksql,p1,p2)
d = fetch(k,ksql,p1,p2,p3)
k |
Kx
Systems®, Inc. kdb+ connection object created with |
ksql |
The Kx Systems, Inc. kdb+ command. |
p1,p2,p3 |
Input parameters for the |
d = fetch(k,ksql) returns data from a Kx
Systems, Inc. kdb+ database in a MATLAB® structure where k is the Kx
Systems, Inc. kdb+ object and ksql is the Kx
Systems, Inc. kdb+ command. ksql can be any valid kdb+ command. The
output of the fetch function is any data resulting from the command
specified in ksql.
d = fetch(k,ksql,p1) executes the command specified in
ksql with one input parameter, and returns the data from this
command.
d = fetch(k,ksql,p1,p2) executes the command with two input
parameters.
d = fetch(k,ksql,p1,p2,p3) executes the command with three input
parameters.
Run the following command from a DOS prompt to specify the port number
5001:
q tradedata.q -p 5001
Connect to a Kx
Systems, Inc. server using IP address 'localhost' and port number
5001:
k = kx('localhost',5001);
Retrieve data using the command 'select from trade':
d = fetch(k,'select from trade');
d =
sec: {5000x1 cell}
price: [5000x1 double]
volume: [5000x1 int32]
exchange: [5000x1 double]
date: [5000x1 double]
Retrieve data, passing an input parameter 'ACME' to the command
'totalvolume':
d = fetch(k,'totalvolume','ACME');
d =
volume: [1253x1 int32] This is the total trading volume for the security ACME in the table
trade. The function totalvolume is defined in the
sample Kx
Systems, Inc. kdb+ file, tradedata.q.