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Dense vs. sparse data format


The example 'indexeg' shows how to read data tables with different formats from a spreadsheet:

  • a dense 3x2 table
  • a dense 2x3 table
  • a sparse 2x3 table

A spreadsheet may be accessed from Mosel through an ODBC connection (using the odbc driver, indexeg.mos, or with SQL statements, indexeg2.mos), with the software-specific driver excel (indexeg3.mos), or with the portable mmsheet module that can be used to read and write xls, xlsx (indexeg5.mos) and csv (indexeg6.mos) files.

The first two methods (odbc driver and SQL statements) apply to spreadsheets and databases. In addition, for Oracle databases we show how to use the software-specific connection provided by the module mmoci (indexeg4.mos).

Further explanation of this example: Xpress Whitepaper 'Using ODBC and other database interfaces with Mosel', Section Examples - Dense vs. sparse data format.

Source Files

Data Files


   Mosel Example Problems 

   file indexeg2.mos
   Using ODBC with dense and sparse format data tables.
   - Using SQL statements -
   (c) 2008 Fair Isaac Corporation
       author: Y. Colombani, 2002, rev. Sep. 2018

model ODBCImpEx2
 uses "mmodbc"

  A: array(1..3, 1..2) of real
  B: array(1..2, 1..3) of real
  C: array(1..2, 1..3) of real
  D: array(R:range, 1..3) of real
  CSTR: string

! CSTR:= 'DSN=Excel Files;DBQ=C:/xpress/examples/mosel/WhitePapers/MoselData/indexeg.xls'
! CSTR:= 'indexeg.xls'

! CSTR:= 'DSN=sqlite;DATABASE=indexeg.sqlite'
 CSTR:= 'indexeg.sqlite'


 ! Data must be dense - there are not enough columns to serve as index!
 SQLexecute("select * from Range3by2 ", A)
 writeln("\n ===A=== ")
 forall(i in 1..3)
  writeln("Row(",i,"): ", A(i,1), " ", A(i,2))
 setparam("SQLndxcol", false)      ! Dense data
 SQLexecute("select * from Range2by3 ", B)
 writeln("\n ===B=== ")
 forall(i in 1..2)
  writeln("Row(",i,"): ", B(i,1), " ", B(i,2), " ", B(i,3))
 setparam("SQLndxcol", true)       ! Indexed data
 SQLexecute("select * from Range2by3i ", C)
 writeln("\n ===C=== ")
 forall(i in 1..2)
  writeln("Row(",i,"): ", C(i,1), " ", C(i,2), " ", C(i,3))

 setparam("SQLndxcol", false)      ! Partially indexed data
 SQLexecute("select * from RectRange ", D)
 writeln("\n ===D=== ")
 forall(i in R)
  writeln("Row(",i,"): ", D(i,1), " ", D(i,2), " ", D(i,3))



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