Voyager + C++ With DBI Part 1: Number Fields

This is part 1 of this subject.  Part 2, using C++ with DBI String Fields, will be in a few weeks, once I figure it out!

Extending the posts relating to using C++ with Cube Voyager, the next thing to look at is using C++ with the DBI input module that was added in Cube 5.1.

The key to making this happen is the Matrix FILEI help section that discusses that certain things are held in arrays. My last post on this subject got into arrays a little, but there are a few new tricks to use.

The code below (C++) is some simple source code that reads the input database (DBI.1) and reads the built-in array of field values.

typedef struct { int I,J,Zones,Iterations;
				double** MW;
				void* (*pfFindVar)(char*,...);
				void* (*pfPrnLine)(int,char*);
} Callstack;

int TableReader (Callstack* Stack){

	double* TableRecord;
	char message[100];

	TableRecord=(double*)Stack->pfFindVar("DBI.1.NFIELD",1,2,3,4,5,6,7,8,9,10,
		11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,
		31,32,33,34,35,36,37,38,39,40);

	for(int x=0;x<=40;x++){ 		if(&TableRecord[x]!=0){ 			sprintf(message,"Table %i=%f",x,TableRecord[x]); 			Stack->pfPrnLine(1,message);
		}
	}

	return 0;
}

This reads all the NUMERIC (note the emphasis!) fields and dumps them to the print file. There is a trick in here - I have a table with 39 fields, but I pull 40 fields. If you actually use that 40th field in the sprintf statement, it crashes. This is why I test to ensure that &TableRecord[x] (the pointer to the table record) does not equal 0.

Normally in Cube, one would read the database fields using DI.1.FIELDNAME. This is certainly possible in C++. Note the code below (where HHPERSONID is the field name):

int TableReader2 (Callstack* Stack){
	double HHPersonId;
	char message[100];

	HHPersonId=*(double*)Stack->pfFindVar("DI.1.HHPERSONID");
	sprintf(message,"%f",HHPersonId);
	Stack->pfPrnLine(1,message);

	return 0;
}

This is similar to the code example above.

Tune in next week when I get into more DBI with C++.

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