Datafeed Toolbox™

kx.fetch - Request data from Kx Systems^®, Inc. kdb+ databases

Syntax

D = fetch(K,KSQL)
D = fetch(K,KSQL,P1)
D = fetch(K,KSQL,P1,P2)
D = fetch(K,KSQL,P1,P2,P3)

Arguments

Description

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 kdb+ command. KSQL can be any valid kdb+ command. The output of this method is any data resulting from the command specified in KSQL.

D = fetch(K,KSQL,P1,P2,P3) executes the command specified in KSQL with one or more input parameters, and returns the data from this command.

Examples

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 select from trade:

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.

See Also

kx.exec, kx.insert, kx

kx.close

kx.get