indexedviewexample.cpp

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

// example illustrating the use of an IndexedDBView for Example objects

#include "IndexedViewExample.h"

const TIMESTAMP_STRUCT then = {2000, 12, 15, 0, 0, 0, 0};

// Example of using an IndexDBView to read, insert and update records in a container / database
void IndexedViewExample()
{
	typedef DBView<Example, ParamObjExample> DBV;

	DBV view("DB_EXAMPLE", DefaultBCA<Example>(), 
	  "WHERE INT_VALUE BETWEEN (?) AND (?) OR "
	  "STRING_VALUE = (?) OR EXAMPLE_DATE <= (?) ORDER BY EXAMPLE_LONG",
	  BPAExampleObj());

	// make the functor needed for SetParams out of SetParamsExample() by calling
	// cb_ptr_fun(SetParamsExample)
	IndexedDBView<DBV> indexed_view(view, "PrimaryIndex; STRING_VALUE; UNIQUE AlternateIndex; EXAMPLE_LONG, EXAMPLE_DATE", 
		BOUND, USE_ALL_FIELDS, 
		cb_ptr_fun(SetParamsExample));

	try
	{
	// Find the item where the STRING_VALUE matches the string "Foozle"
	IndexedDBView<DBV>::indexed_iterator idxview_it = indexed_view.find(string("Foozle"));
		

	// Update the item with the key of "Foozle", to read "Fizzle" instead
	if (idxview_it != indexed_view.end()) {
		Example replacement;
		replacement = *idxview_it;
		replacement.SetExampleStr("Fizzle");
		TIMESTAMP_STRUCT date = {2003, 3, 3, 0, 0, 0, 0};
		replacement.SetExampleDate(date);
		indexed_view.replace(idxview_it, replacement);
	}

	// Now find a second set of items using AlternateIndex
	// The STL convention for equal_range is to return a pair consisting of:  
	// 1. an iterator referring to the beginning of the list of found items
	// 2. an iterator pointing to the end of the list of found items. 
	// We will remove all items in this range.
	const TIMESTAMP_STRUCT ts_date_criteria = {2000, 1, 1, 0, 0, 0, 0};
	jtime_c date_criteria(ts_date_criteria);
	long long_criteria = 33;
	IndexedDBView<DBV>::indexed_pair pr = indexed_view.equal_range_AK ("AlternateIndex", long_criteria, date_criteria);

	idxview_it = pr.first;

	cout << "*** Size before erase calls: " << indexed_view.size() << " ***"
	<< endl;
		
	// Remove all items that match the criteria in our equal_range_AK lookup
	while (idxview_it != pr.second)
	{
		// As iterator is invalidated upon an erase(), use a
		// temporary iterator to point to DataObj to erase.
		// Increment idxview_it before we erase so it will still be valid
		// when we erase the DataObj.
		IndexedDBView<DBV>::indexed_iterator deleteMe = idxview_it;

		++idxview_it;

		indexed_view.erase(deleteMe);

	}

	cout << "*** Size after erase calls: " << indexed_view.size() << " ***"
		 << endl;


	// Insert a new item into the container
	pair<IndexedDBView<DBV>::iterator, bool> ins_pr;

  cout << "We will now try to insert three items.  Only the first item will succeed!" << endl;

	ins_pr = indexed_view.insert(Example(459, "Unique String #1", 3.4, 1, date_criteria));

	cout << "insertion succeded = " << (ins_pr.second == true ? "true": "false") << endl;

	ins_pr = indexed_view.insert(Example(311, "", 3.99, 91, then)); // should fail on InsValidate()
   
	cout << "insertion succeded = " << (ins_pr.second == true ? "true": "false") << endl;
	
	ins_pr = indexed_view.insert(Example(222, "Positron", -34.77, 29, then)); // should fail (ditto)
	
	cout << "insertion succeded = " << (ins_pr.second == true ? "true": "false") << endl;
	}
	
	catch (...)
	{
	typedef LoggingHandler<Example, ParamObjExample>::LoggedTriple LoggedTriple;
 
	// retrieve the LoggingHandler object from the IndexedDBView
	LoggingHandler<Example, ParamObjExample> log_handler = 
		indexed_view.get_io_handler((LoggingHandler<Example, ParamObjExample> *) NULL);

    // the log is a vector of (error message, DataObj, ParamObj) triples,
    // (error message, Example object, ParamObjExample object) in this case
    // the error itself along with the relevant DataObj and ParamObj that resulted with
    // the error
    vector<LoggedTriple> error_log = log_handler.GetLog();

    // nothing to do if no errors occurred
    if (error_log.empty())
	    return;

    cout << "*** Error Log in IndexedViewExample(): " << error_log.size() << " errors recorded! ***"
	     << endl;

    // print out the errors
    for (vector<LoggedTriple>::const_iterator log_it = error_log.begin(); 
		log_it != error_log.end(); log_it++)
	{
       cout << "*** Error Log Entry ***" << endl;
	   cout << "* error message *" << endl;
	   cout << (*log_it).errmsg << endl;
	   cout << "* relevant Example object *" << endl;
	   cout << (*log_it).dataObj << endl;
	}

	}	
}