Dataframe formats

This example demonstrates dataframe-style representation of data. This functionality is provided for CSV format files via the 'diskdata' I/O driver and subroutine of module mmetc and for databases accessed through an ODBC connection via SQL commands.

• dataframecsv.mos: reading and writing dataframes for CSV format data
• dataframedb.mos: dataframe-style reading of database tables via 'SQLdataframe'

(!******************************************************
   Mosel Example Problems
   ======================

   file dataframecsv.mos
   `````````````````````
   Dataframe functionality for reading and writing CSV files
   via 'diskdata' (I/O driver and subroutine)
   
  (c) 2021 Fair Isaac Corporation
      author: S.Heipcke, Oct 2021
*******************************************************!) 
model 'dataframecsv'
 uses 'mmsystem', 'mmetc'

 public declarations
   data=`
C_e,C_d,C_c,C_b,C_a,C_s
1,,"3",4,5.5,"r1"
6,7,"8",,10.5,"r2"
`
   datanh=`
1,,"3",4,5.5,"r1"
6,7,"8",,10.5,"r2"
`
 end-declarations

 CSVFILE:="text:data"
 CSVFILENH:="text:datanh"

!*** I/O driver version populating row counter and column (field names) indices
 declarations
   dfd: dynamic array(r:range, s:set of string) of text
   dff: array(rf:range, sf:set of string) of text
   dfa: dynamic array(ra:range, sa:set of string) of any
 end-declarations
 initialisations from 'mmetc.diskdata:'
   dfd as "dataframe;skiph;"+CSVFILE
   dff as "dataframe;skiph;"+CSVFILE
   dfa as "dataframe;skiph;"+CSVFILE
 end-initialisations
 writeln("dyn:", dfd.size, " dns:", dff.size) ! Output displayed: dyn:10 dns:12
 writeln(dfa)
 initialisations to 'mmetc.diskdata:'
   dfd as "dataframe;skiph;res.csv"           ! Output CSV file with header line
   dfd as "dataframe;resnh.csv"               ! Output CSV file without header
 end-initialisations

!*** Subroutine version populating row counter and column (field names) indices
 declarations
   dfd1: dynamic array(r1:range, s1:set of string) of text
   dff1: array(r1f:range, s1f:set of string) of text
   dfa1: dynamic array(ra1:range, sa1:set of string) of any
 end-declarations
 diskdata(ETC_DATAFRAME+ETC_SKIPH, CSVFILE, dfd1)
 diskdata(ETC_DATAFRAME+ETC_SKIPH, CSVFILE, dff1)
 diskdata(ETC_DATAFRAME+ETC_SKIPH, CSVFILE, dfa1)
 writeln("dyn:", dfd.size, " dns:", dff.size) ! Output displayed: dyn:10 dns:12
 writeln(dfa1)
! Output CSV file with and without header line
 diskdata(ETC_SKIPH+ETC_OUT+ETC_CSV+ETC_DATAFRAME, "res1.csv", dfd1)
 diskdata(ETC_OUT+ETC_CSV+ETC_DATAFRAME, "resnh1.csv", dfd1)

!*** No header line
 declarations
   dfd2: dynamic array(r21:range, r2:range) of text
 end-declarations
 initialisations from 'mmetc.diskdata:'
   dfd2 as "dataframe;"+CSVFILENH
 end-initialisations
! Same as:
! diskdata(ETC_DATAFRAME, CSVFILENH, dfd2)
 writeln("size df2=", dfd2.size)            ! Output displayed: size df2=10
 writeln("r1=", r21, " r2=", r2)            ! Output displayed: r1=1..2 r2=1..6

!*** Selection of fields
 declarations
   dfd3: dynamic array(r3:range,s3:set of string) of any
 end-declarations
 initialisations from 'mmetc.diskdata:'
   dfd3 as "dataframe;skiph;csv(C_d,C_b);"+CSVFILE
 end-initialisations
 writeln("size df3=", dfd3.size)            ! Output displayed: size df3=2

!*** Fixed number of rows
 declarations
   dfd4: dynamic array(1..1,s4:set of string) of text
 end-declarations
 initialisations from 'mmetc.diskdata:'
   dfd4 as "dataframe;skiph;"+CSVFILE
 end-initialisations
! Same as:
! diskdata(ETC_DATAFRAME+ETC_SKIPH, CSVFILE, df4)
 writeln("size df4=", dfd4.size)           ! Output displayed: size df4=5

!*** Typed (integer) array
 declarations
   dfi: dynamic array(ri:range,si:set of string) of integer
 end-declarations
! Reading data of other types into an integer array will result in an
! I/O error: instead of stopping we continue to display what has been read
 setparam("ioctrl",true)
  initialisations from 'mmetc.diskdata:'
   dfi as "dataframe;skiph;"+CSVFILE
 end-initialisations
! Same as:
! diskdata(ETC_DATAFRAME+ETC_SKIPH, CSVFILE, dfi)
 setparam("ioctrl",false)
 if getparam("iostatus")<>0 then
   writeln("Error reading input file, interrupted in line ", ri.size)
 end-if
! Display what we have managed to read
 writeln(dfi, " size dfi=", dfi.size)      ! Ouput displayed: size dfi=4
end-model

(!******************************************************
   Mosel Example Problems
   ======================

   file dataframedb.mos
   ````````````````````
   Working with SQL dataframe functionality
   
  (c) 2021 Fair Isaac Corporation
      author: S.Heipcke, Oct 2021
*******************************************************!) 
model 'dataframedb'
options keepassert
uses 'mmodbc','mmsystem'

! **** Database creation ****
procedure createDB(cstr:string)
 declarations
  REC=1..7
  article,owner: array(REC) of integer
  dealer,style,color: array(REC) of string
  price: array(REC) of real
 end-declarations
 
 article::[1,1,2,3,3,3,4]
 dealer::['A','B','A','B','C','D','D']
 price::[3.45,3.99,10.99,1.45,1.69,1.25,19.95]
 style::['polo','dress','t-shirt','dress', 'polo','dress','t-shirt']
 color::['blue','white','blue',   'orange','red', 'blue', 'white']
 owner::[1,1,1,2,2,2,2]

 writeln("Creating tables for `sdkdatafrm'")
 SQLconnect(cstr)

 SQLexecute("drop table if exists shop")
 SQLexecute("create table shop (article integer, owner varchar(10))")
 assert(getparam("SQLsuccess"))
 forall(i in REC) do
   SQLexecute("insert into shop (article,owner) values (?,?)",
       [article(i),dealer(i)] )
   assert(getparam("SQLsuccess"))
 end-do

 SQLexecute("drop table if exists shirts")
 SQLexecute("create table shirts (id integer, style varchar(10),"+
       "price float, color varchar(10), owner integer)")
 assert(getparam("SQLsuccess"))

 SQLexecute("insert into shirts (id,style,price,color,owner) values (?,?,?,?,?)",
       [style,price,color,owner])
 assert(getparam("SQLsuccess"))

 SQLdisconnect
end-procedure

! ************ Reading all or selected fields from database tables ************
procedure readtests
 declarations
  dfa:array(ra:range,csa:set of string) of any
  dft:array(rt:range,cst:set of string) of text
  dfi:array(ri:range,csi:set of string) of integer
  dfa2:array(ra2:range,csa2:set of string) of any
 end-declarations

 writeln("+ All columns (any)")
 SQLdataframe("select * from shirts", dfa)
 writeln("csa: ", csa," ra: ", ra)
 writeln("dfa: ", dfa)          ! Typed data
 writeln(sum(i in ra) dfa(i,"owner").integer)
 writeln

! Select some columns and specify new name for one of them
 writeln("+ Index set initialised and column selection (text)")
 SQLdataframe("select id as prod,color as couleur,style from shirts", dft)
 writeln("cst: ", cst," rt: ", rt)
 writeln("dft: ", dft)          ! All data as text
 writeln

! A typed array is accepted, but only fields with matching types are read
 writeln("+ As integer")
 SQLdataframe("select * from shirts", dfi)
 writeln("csi: ", csi," ri: ", ri)
 writeln("dfi: ", dfi)          ! Typed data
 writeln(sum(i in ri,j in csi) dfi(i,j))
 writeln

! Can handle data from multiple tables, in the case of multiple occurrences
! of field names unique names are generated
 writeln("+ Duplicate names in columns")
 SQLdataframe("select * from shirts inner join shop on id=article", dfa2)
 writeln("csa2: ", csa2," ra2: ", ra2)
 writeln("dfa2: ", dfa2) 
 writeln
end-procedure

! ************ Using SQLupdate with a dataframe structure ************

procedure testupdate
 declarations
  dfa:array(ra:range,csa:set of string) of text or any
  dft:array(rt:range,cst:set of string) of text
  Idx: text
 end-declarations

! Reading union type dataframe structure
 SQLdataframe("select * from shirts", dfa)
 writeln("Original df: ", dfa)
 writeln
 forall(i in ra) dfa(i,"price"):=dfa(i,"price").real+10
 forall(i in ra) dfa(i,"style"):=dfa(i,"style").text+"_xyz"
 writeln("Modified df: ", dfa)

 k:=0
 forall(j in csa-{'id'}, k as counter) Idx+=(if(k>1, ", "+j, j)+"=?"+(k+1))
 query:="update shirts set "+Idx+" where id=?1"
 writeln(query)

 finalise(csa)                    ! Required for 'SQLndxcol=false'
 setparam("SQLndxcol", false)     ! Partially indexed data
 SQLexecute(query, dfa)

! Dislay new table contents
 SQLdataframe("select * from shirts",dft)
 writeln("dft: ", dft)
end-procedure

!**********************************************************

! Create the database
 createDB("dbtest.sqlite")
 setparam("SQLdebug",true)
 setparam("SQLverbose",true)
 SQLconnect("dbtest.sqlite")
 assert(getparam("SQLsuccess"))

! Run data reading and writing procedures
 readtests
 testupdate

 SQLdisconnect

end-model