#shell and #sqlThe #shell script directive may be used to invoke a shell command and capture the results.
The #sql script directive invokes an SQL command and captures the results. The #sql directive is currently available only for builds related to the QUISP/SHSQL package. Interfaces to other databases (MySQL, Oracle, etc.) not yet available but should be possible by coding in dbinterface.c.
Note that both of these are of limited value in ploticus... proc getdata already
has a command attribute for getting data from shell command results, and it
also has a sql attribute for running an SQL command. They should be viewed
as providing an alternative approach.
STREAMING DATAHere is an example of how #sql is to be used with proc getdata :
#proc getdata delim: tab data: #sql #dumptab select * from trialresults where trialnum = @TRIALNUM
For longer SQL commands a multi-line construct is available:
#proc getdata delim: tab data: #sql #dumptab select trialnum, age, sex, weight, time1, time2 from trialresults where trialnum = @TRIALNUM and trialdate = @TDATE #endsqlThe #shell directive can be used similary, but this is redundant since proc getdata already has a command attribute.
SETTING VARIABLESThese directives may be used to set variables for plot labels, etc. For example:
#sql #load select fullname from tsyms where tickersym = @TSYM #proc annotate location: min max-0.2 text: @fullname
Here is an example where the results of a shell command may be used to set variables:
// submit the command.. #shell #processrows cat mydata | grep "^Jan" // get one result rows and parse out fields.. #call $shellrow( A, B, C ) #proc annotate location: min max-0.2 text: @A @B
DRIVING LOOPSThese directives may be used to drive loops that iterate once per row of results. For example:
// get a list of cases #sql #processrows select caseid from cases #while $sqlrow() = 0 // get data for a case #proc getdata delim: tab data: #sql2 #dumptab select * from casedata where caseid = @caseid ... plot the case #endloop
may be used similary.
data display engine
Copyright Steve Grubb
|Ploticus is hosted at http://ploticus.sourceforge.net|