private FilterItem copyFilterItem(FilterItem item, Object[] values, NAtomicInteger parameterIndex)
{
if (item.isCompoundFilter())
{
FilterItem[] childItems = item.getChildItems();
FilterItem[] newChildItems = new FilterItem[childItems.Length];
for (int i = 0; i < childItems.Length; i++)
{
FilterItem childItem = childItems[i];
FilterItem newChildItem = copyFilterItem(childItem, values, parameterIndex);
newChildItems[i] = newChildItem;
}
NList <FilterItem> elements = new NList <FilterItem>();
foreach (FilterItem element in newChildItems)
{
elements.Add(element);
}
FilterItem newFilter = new FilterItem(item.getLogicalOperator(), elements);
return(newFilter);
}
else
{
if (item.getOperand() is QueryParameter)
{
Object newOperand = values[parameterIndex.getAndIncrement()];
FilterItem newFilter = new FilterItem(item.getSelectItem(), item.getOperator(), newOperand);
return(newFilter);
}
else
{
return(item);
}
}
} // copyFilterItem()
private void buildParameterFromFilterItem(List <QueryParameter> parameters, FilterItem item)
{
if (item.isCompoundFilter())
{
FilterItem[] childItems = item.getChildItems();
foreach (FilterItem childItem in childItems)
{
buildParameterFromFilterItem(parameters, childItem);
}
}
else
{
if (item.getOperand() is QueryParameter)
{
parameters.Add((QueryParameter)item.getOperand());
}
}
}
} // constructor
public DataSet executeQuery(Query query)
{
List <SelectItem> selectItems = query.getSelectClause().getItems();
List <FromItem> fromItems = query.getFromClause().getItems();
List <FilterItem> whereItems = query.getWhereClause().getItems();
List <SelectItem> whereSelectItems = query.getWhereClause().getEvaluatedSelectItems();
List <GroupByItem> groupByItems = query.getGroupByClause().getItems();
List <SelectItem> groupBySelectItems = query.getGroupByClause().getEvaluatedSelectItems();
List <SelectItem> havingSelectItems = query.getHavingClause().getEvaluatedSelectItems();
List <SelectItem> orderBySelectItems = query.getOrderByClause().getEvaluatedSelectItems();
List <FilterItem> havingItems = query.getHavingClause().getItems();
List <OrderByItem> orderByItems = query.getOrderByClause().getItems();
int firstRow = (query.getFirstRow() == null ? 1 : query.getFirstRow());
int maxRows = (query.getMaxRows() == null ? -1 : query.getMaxRows());
if (maxRows == 0)
{
// no rows requested - no reason to do anything
return(new EmptyDataSet(selectItems));
}
// check certain common query types that can often be optimized by
// subclasses
bool singleFromItem = fromItems.Count == 1;
bool noGrouping = groupByItems.IsEmpty() && havingItems.IsEmpty();
if (singleFromItem && noGrouping)
{
FromItem fromItem = query.getFromClause().getItem(0);
Table table = fromItem.getTable();
if (table != null)
{
// check for SELECT COUNT(*) queries
if (selectItems.Count == 1)
{
SelectItem selectItem = query.getSelectClause().getItem(0);
if (SelectItem.isCountAllItem(selectItem))
{
bool functionApproximationAllowed = selectItem.isFunctionApproximationAllowed();
if (isMainSchemaTable(table))
{
logger.debug("Query is a COUNT query with {} where items. Trying executeCountQuery(...)",
whereItems.Count);
NNumber count = executeCountQuery(table, whereItems, functionApproximationAllowed);
if (count == null)
{
logger.debug(
"DataContext did not return any count query results. Proceeding with manual counting.");
}
else
{
List <Row> data = new List <Row>(1);
DataSetHeader header = new SimpleDataSetHeader(new SelectItem[] { selectItem });
data.Add(new DefaultRow(header, new Object[] { count }));
return(new InMemoryDataSet(header, data));
}
}
}
}
bool is_simple_select = isSimpleSelect(query.getSelectClause());
if (is_simple_select)
{
// check for lookup query by primary key
if (whereItems.Count == 1)
{
FilterItem whereItem = whereItems[0];
SelectItem selectItem = whereItem.getSelectItem();
if (!whereItem.isCompoundFilter() && selectItem != null && selectItem.getColumn() != null)
{
Column column = selectItem.getColumn();
if (column.isPrimaryKey() && OperatorType.EQUALS_TO.Equals(whereItem.getOperator()))
{
logger.debug(
"Query is a primary key lookup query. Trying executePrimaryKeyLookupQuery(...)");
if (table != null)
{
if (isMainSchemaTable(table))
{
Object operand = whereItem.getOperand();
Row row = executePrimaryKeyLookupQuery(table, selectItems, column, operand);
if (row == null)
{
logger.debug(
"DataContext did not return any GET query results. Proceeding with manual lookup.");
}
else
{
DataSetHeader header = new SimpleDataSetHeader(selectItems);
return(new InMemoryDataSet(header, row));
}
}
}
}
}
}
// check for simple queries with or without simple criteria
if (orderByItems.IsEmpty())
{
DataSet ds = null;
// no WHERE criteria set
if (whereItems.IsEmpty())
{
ds = materializeTable(table, selectItems, firstRow, maxRows);
return(ds);
}
ds = materializeTable(table, selectItems, whereItems, firstRow, maxRows);
return(ds);
}
}
}
}
// Creates a list for all select items that are needed to execute query
// (some may only be used as part of a filter, but not shown in result)
List <SelectItem> workSelectItems = CollectionUtils.concat(true, selectItems, whereSelectItems,
groupBySelectItems, havingSelectItems, orderBySelectItems);
// Materialize the tables in the from clause
DataSet[] fromDataSets = new DataSet[fromItems.Count];
for (int i = 0; i < fromDataSets.Length; i++)
{
FromItem fromItem = fromItems[i];
fromDataSets[i] = materializeFromItem(fromItem, workSelectItems);
}
// Execute the query using the raw data
DataSet dataSet = null; // MetaModelHelper.getCarthesianProduct(fromDataSets, whereItems);
// we can now exclude the select items imposed by the WHERE clause (and
// should, to make the aggregation process faster)
workSelectItems = CollectionUtils.concat(true, selectItems, groupBySelectItems, havingSelectItems,
orderBySelectItems);
if (groupByItems.Count > 0)
{
dataSet = MetaModelHelper.getGrouped(workSelectItems, dataSet, groupByItems);
}
else
{
dataSet = MetaModelHelper.getAggregated(workSelectItems, dataSet);
}
dataSet = MetaModelHelper.getFiltered(dataSet, havingItems);
if (query.getSelectClause().isDistinct())
{
dataSet = MetaModelHelper.getSelection(selectItems, dataSet);
dataSet = MetaModelHelper.getDistinct(dataSet);
dataSet = MetaModelHelper.getOrdered(dataSet, orderByItems);
}
else
{
dataSet = MetaModelHelper.getOrdered(dataSet, orderByItems);
dataSet = MetaModelHelper.getSelection(selectItems, dataSet);
}
dataSet = MetaModelHelper.getPaged(dataSet, firstRow, maxRows);
return(dataSet);
} // executeQuery()