joinexample.cpp

The goal of this library is to make ODBC recordsets look just like an STL container. As a user, you

// join example data class ... note the class declaration is now free of any of these DB
// abstractions
// Initial: 9/5/2000 - MG
// Reviewed: 11/12/2000 - CJ
// Edited: 12/20/2000 - MG - added namespace support

#include "JoinExample.h"
using namespace dtl;

void SetParamsJoinExample(JoinParamObj &params)
{
	// assign paramteter values
	params.intValue = 3;
	params.strValue = "Join Example";
	params.sampleInt = 1;
	params.sampleStr = "Joined Tables";
}

// let's read some JoinExample objects from the database and return a vector of
// the results
vector<JoinExample> ReadJoinedData()
{
	vector<JoinExample> results;

	// assume connection has been declared somewhere as:
	// DBConnection conn("UID=txupz;PWD=txupz;DSN=posp;");

	// construct view
	// note here that we use a custom parameter object class for JoinExample
	// rather than DefaultParamObj<JoinExample>
	// we also use a custom SelValidate function here: IntValuePosSelValidate
	DBView<JoinExample, JoinParamObj> view("DB_EXAMPLE, DB_SAMPLE", 
		DefaultBCA<JoinExample>(),
		"WHERE (INT_VALUE = (?) AND STRING_VALUE = (?)) AND "
		"(SAMPLE_INT = (?) OR SAMPLE_STR = (?)) ORDER BY SAMPLE_LONG",
		BPAJoinParamObj(), IntValuePosSelValidate());

	// loop through query results and add them to our vector
	// read_it.GetLastCount() records read in this loop

	DBView<JoinExample, JoinParamObj>::select_iterator
		read_it = view.begin();

	// assign paramteter values
	read_it.Params().intValue = 3;
	read_it.Params().strValue = "Join Example";
	read_it.Params().sampleInt = 1;
	read_it.Params().sampleStr = "Joined Tables";

	for ( ;  read_it != view.end();  read_it++)
    {
		
		// note that the read_iterator::GetLastCount()  is incremented in operator++()
		// remember that the record is fetched and thus the count incremented
		// before operator*() is applied to the read_iterator
		
		cout << "Reading element #" << read_it.GetLastCount() << endl;
		results.push_back(*read_it);

		cout << *read_it << endl;
	}

	return results;
}

// read JoinExamples from indexed view to make sure data gets in IndexedDBView's
// internal list<DataObj> properly
vector<JoinExample> ReadJoinedDataFromIndexedView()
{
	DBView<JoinExample, JoinParamObj>
		view("DB_EXAMPLE, DB_SAMPLE", 
		DefaultBCA<JoinExample>(),
		"WHERE (INT_VALUE = (?) AND STRING_VALUE = (?)) AND "
		"(SAMPLE_INT = (?) OR SAMPLE_STR = (?)) ORDER BY SAMPLE_LONG",
		BPAJoinParamObj(), IntValuePosSelValidate());

	// here, we are not too concerned about the indices themselves
	// we're just testing to see if the DataObj's are stored properly in the
	// indexed view's internal list
    IndexedDBView<DBView<JoinExample, JoinParamObj> > 
		indexed_view(view, "IndexLong; SAMPLE_LONG", 
		UNBOUND, USE_ALL_FIELDS, cb_ptr_fun(SetParamsJoinExample));

	vector<JoinExample> results_from_indexed_view;

	// populate results vector with the data from the indexed view
	for (IndexedDBView<DBView<JoinExample, JoinParamObj> >::iterator 
		    data_it = indexed_view.begin(); data_it != indexed_view.end(); data_it++)
	{
		results_from_indexed_view.push_back(*data_it);
	}

	cout << "*** IndexedDBView size is: " << results_from_indexed_view.size() << " ***" << endl; 

	return results_from_indexed_view;
}
// read Examples from indexed view that have the given DataObj as (primary) key
vector<JoinExample> ReadJoinedFilteredDataPK(JoinExample &key)
{
   	DBView<JoinExample, JoinParamObj>
		view("DB_EXAMPLE, DB_SAMPLE", 
		BCAJoinExampleObj(),
		"WHERE (INT_VALUE = (?) AND STRING_VALUE = (?)) AND "
		"(SAMPLE_INT = (?) OR SAMPLE_STR = (?)) ORDER BY SAMPLE_LONG",
		BPAJoinParamObj(), IntValuePosSelValidate());

	// here, we are not too concerned about the indices themselves
	// we're just testing to see if the DataObj's are stored properly in the
	// indexed view's internal list
    IndexedDBView<DBView<JoinExample, JoinParamObj> > 
		indexed_view(view, "IndexLong; SAMPLE_LONG",
		UNBOUND, USE_ALL_FIELDS, cb_ptr_fun(SetParamsJoinExample));

	vector<JoinExample> filtered_results;

	// the return value consists of a pair: 1. an iterator referring to the found items
	// and 2. an iterator pointing to the end of the list of found items 
	IndexedDBView<DBView<JoinExample, JoinParamObj> >::indexed_pair 
		    pr = indexed_view.equal_range(key);

	IndexedDBView<DBView<JoinExample, JoinParamObj> >::indexed_iterator
		    idx_data_it = pr.first;

	IndexedDBView<DBView<JoinExample, JoinParamObj> >::indexed_iterator
			end_it = pr.second;

	IndexedDBView<DBView<JoinExample, JoinParamObj> >::indexed_iterator
			find_it = indexed_view.find(key);

	if (idx_data_it == find_it)
		cout << "Iterator integrity satisfied!" << endl;

	// need to be able to iterate through found results
	for ( ; idx_data_it != end_it; idx_data_it++)
	{
		// first * dereferences the iterator, returning a DataObj *
		// second * dereferences the DataObj *, yielding a DataObj
		JoinExample &idx_data = *idx_data_it;
		filtered_results.push_back(idx_data);
	}

	cout << filtered_results.size() << " results found!" << endl;
	return filtered_results;

}