SQL2GMS - GAMS

6
SQL2GMS
new york 100
los angeles 120
san francisco 105
washington dc 102
This means we have to map ‘new york' to ‘NY' etc. This mapping can be done in two places: either in
GAMS or in the database.
When we export the table directly (with the option ‘Quote Blanks' turned on), we get:
* -----------------------------------------------------
* SQL2GMS Version 3.0, November 2006
* Erwin Kalvelagen, GAMS Development Corp
* -----------------------------------------------------
* ADO version: 2.8
* Connection string: Driver={Microsoft Access Driver (*.mdb)}; Dbq=d:
\sql2gms\sample.mdb
* Provider: MSDASQL
* Query: SELECT city, value
* FROM [example table]
* -----------------------------------------------------
'new york' 100
'los angeles' 120
'san francisco' 105
'washington dc' 102
* -----------------------------------------------------
As the index elements contain blanks, the option Quote Blanks was used. To import this file and
convert it to a different index space we can use the following GAMS code:
set i /NY,DC,LA,SF/;
set idb 'from database' /
'new york',
'washington dc',
'los angeles',
'san francisco'
/;
parameter dbdata(idb) /
$include data.inc
/;
set mapindx(i,idb) /
NY.'new york'
DC.'washington dc'
LA.'los angeles'
SF.'san francisco'
/;
parameter data(i);
data(i) = sum(mapindx(i,idb), dbdata(idb));
display data;
The second approach is to handle the mapping inside the database. We can introduce a mapping table
that looks like:
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