Problems with import of data from a database

Hello,

i try to import data from a database to my model. I do this every day in the simulation and use the following program code:

int day = (time() / 1440 + 1);
string ODBCname = "Flexsim Database";
string query = concat("SELECT Ma_BrukteMonster.* FROM Ma_Brukte WHERE Ma_Brukte.Dag =",numtostring(day));
dbopen(ODBCname,query,0);
dbviewtable();
dbclose();

The problem is that it doesn't run stabile. Sometimes I get the table with the data and sometimes not. I think the problem is that there are no data for some days and that results in an empty table in Flexsim and that is something Flexsim doesn't like. But actually I have no real idea what causes this failure.

Does someone knows a possible cause for it? Thanks in advance,

Matthias

Mattias,

The problem is in the dbopen() command. It doesn't work correctly when the query returns an empty table. This is something we'll need to look into. What I've done in the past to get around that is to make sure that the initial query always retrieves something, even if it's not data that you actually plan to use. I typically use a simple SELECT statement on a small table in the database.

Then, once the dbopen() command has succeeded, you can use the dbsqlquery() command to call the query that you really want to use. This command does not have the same problem with empty sets that dbopen() does.