// "Example" class to hold rows from our database table
class Example
{
public: // tablename.columnname:
int exampleInt; // DB_EXAMPLE.INT_VALUE
string exampleStr; // DB_EXAMPLE.STRING_VALUE
double exampleDouble; // DB_EXAMPLE.DOUBLE_VALUE
long exampleLong; // DB_EXAMPLE.EXAMPLE_LONG
TIMESTAMP_STRUCT exampleDate; // DB_EXAMPLE.EXAMPLE_DATE
Example(int exInt, const string &exStr, double exDouble, long exLong,
const TIMESTAMP_STRUCT &exDate) :
exampleInt(exInt), exampleStr(exStr), exampleDouble(exDouble), exampleLong(exLong),
exampleDate(exDate)
{ }
};
// Parameter object to hold parameters for dynamic SQL query below
class ParamObjExample
{
public:
int lowIntValue;
int highIntValue;
string strValue;
TIMESTAMP_STRUCT dateValue;
};
// Create an association between table columns and fields in our object
class BCAExampleObj
{
public:
void operator()(BoundIOs &boundIOs, Example &rowbuf)
{
boundIOs["INT_VALUE"] == rowbuf.exampleInt;
boundIOs["STRING_VALUE"] == rowbuf.exampleStr;
boundIOs["DOUBLE_VALUE"] == rowbuf.exampleDouble;
boundIOs["EXAMPLE_LONG"] == rowbuf.exampleLong;
boundIOs["EXAMPLE_DATE"] == rowbuf.exampleDate;
}
};
// Create an association between query parameters and fields in our parameters object
class BPAExampleObj
{
public:
void operator()(BoundIOs &boundIOs, ParamObjExample ¶mObj)
{
boundIOs[0] == paramObj.lowIntValue;
boundIOs[1] == paramObj.highIntValue;
boundIOs[2] == paramObj.strValue;
boundIOs[3] == paramObj.dateValue;
}
};
// Set parameters function for Example ... used by IndexedDBView<Example> to set dynamic query parameters
// Dynamic query parameters are indicated by (?) in our query string for the IndexedDBView
void SetParamsExample(ParamObjExample ¶ms)
{
// set parameter values
params.lowIntValue = 2;
params.highIntValue = 8;
params.strValue = "Example";
TIMESTAMP_STRUCT paramDate = {2000, 1, 1, 0, 0, 0, 0};
params.dateValue = paramDate;
}
// 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", BCAExampleObj(),
"WHERE INT_VALUE BETWEEN (?) AND (?) OR "
"STRING_VALUE = (?) OR EXAMPLE_DATE <= (?) ORDER BY EXAMPLE_LONG",
BPAExampleObj());
IndexedDBView<DBV> indexed_view(view, "UNIQUE PrimaryIndex; STRING_VALUE; AlternateIndex; EXAMPLE_LONG, EXAMPLE_DATE",
BOUND, USE_ALL_FIELDS, cb_ptr_fun(SetParamsExample));
// Find the item where the STRING_VALUE matches the string "Foozle"
IndexedDBView<DBV>::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.exampleStr = "Fizzle";
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 date_criteria = {2000, 1, 1, 0, 0, 0, 0};
long long_criteria = 33;
pair<IndexedDBView<DBV>::iterator, IndexedDBView<DBV>::iterator> 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>::iterator deleteMe = idxview_it;
idxview_it++;
indexed_view.erase(deleteMe);
}
cout << "*** Size after erase calls: " << indexed_view.size() << " ***"
<< endl;
// Finally, insert a new item into the container
pair<IndexedDBView<DBV>::iterator, bool> ins_pr;
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;
}