OOFile Manual

OOFTST 38 - no-nulls indices

This sample tests the use of indices that ignore nulls it also shows a trick to use a compound index to get effectively multiple indexes on the same field

#include "oofile.h"	// the general oofile library

We start by declaring a class. Note that we have declared a dbCompoundField for more on compound fields, see ooftst12. Note that we have declared the index for F2 as being no nulls and no duplicates.

DECLARE_CLASS(dbTest38)
	dbChar			name;
	dbUlong			f2;
	dbReal			f3; 
	dbCompoundField	secondName;

	dbTest38() : 
		name(20, "name", kIndexCompress),
		f2("F2", kIndexNoDupsNoNulls),
		f3("F3"),
		secondName("second name", kIndexCompressNoNulls)
{

This is not really a compound index, just a different kind of index.

	secondName << name;	
};
	};

This shows a common technique, using our own class to contain all the database

class test38DB : public dbConnect_ctree
{
public:
	void	addTestData(unsigned long startNum, unsigned long endNum);
	void	displaySorted(dbField& sortField);

Here we have our table.

	dbTest38     	 mTable;

};

This procedure add the test data to our database table.

void
test38DB::addTestData(unsigned long startNum, unsigned long endNum)
{

Here we declare an array of strings to use for intialising the name fields of the database. The null entries will not be indexed by secondName.

	const char* names[] = {
		"Andy",
		"Fred",
		"Sally",
		"Zach",
		"" 
	};
	const unsigned short kNumNames =  sizeof(names)/sizeof(const char*);
	for (unsigned long i=startNum; i<endNum; i++) {
		mTable.newRecord();
		const unsigned short iName = i%kNumNames;
		mTable.name = names[iName];	// one of 5 names
		mTable.f2 = i;
		mTable.f3 = i+0.5;
		mTable.saveRecord();
	}
}

This procedure is passed a field by reference and displays it. It also demonstrates the function fieldName() that can be used to find the name of a field passed by pointer.

Testing: function fieldName()

void
test38DB::displaySorted(dbField& sortField)
{
	mTable.setSortOrder(sortField);
	cout 
		<< "Sorted by " 
		<< sortField.fieldName() 
		<< " has " << mTable.count() << " records\n"
		<< mTable
		<< endl << endl;
}

int main()
{
	cout << "OOFILE Validation Suite - Test 38\n"
		 << "This tests the effect of adding indices to a database\n\n";

We declare our global variables then open the database.

	test38DB  theDB;

	const char* kDatabaseName = "ooftst38.db";
	if (dbConnect::fileExists(kDatabaseName)) {
		theDB.openConnection(kDatabaseName);
		theDB.deleteAll();
	}
	else {
		cout << "Creating a new database\n";
		theDB.newConnection(kDatabaseName);
	}

We add 5 records to the database (this should include at least one instance of the null field).

	cout << "Adding 5 test records\n";
	theDB.addTestData(0, 5);

Now we will display each of the fields in turn, showing which ones have and have not been added.

	theDB.displaySorted(aDB.mTable.name);
	theDB.displaySorted(aDB.mTable.secondName);
	theDB.displaySorted(aDB.mTable.f2);
	theDB.displaySorted(aDB.mTable.f3);

	cout << endl <<"Test Completed" << endl;

	return EXIT_SUCCESS;
}

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