public EmbeddedQueryContext(ITable backedTable, SystemTransaction transaction, object syncObject)
{
this.syncObject = syncObject;
isClosed = false;
this.backedTable = backedTable;
// Determine the updatability of the result set
notNotUpdatableReason = null;
// If the result set is a mutable table data source object,
if (backedTable is IMutableTable) {
updatableView = new UpdatableResultSetView(transaction, (IMutableTable) backedTable, null, backedTable.GetRowCursor());
} else {
// Can we map this to a native table?
TableName nativeTableName = QueryProcessor.GetNativeTableName(backedTable);
// If we can,
if (nativeTableName != null) {
// The top table must be an operation table and must have all
// FETCHVAR operations,
if (backedTable is ExpressionTable) {
ExpressionTable expressionTable = (ExpressionTable)backedTable;
Expression[] projectionExps = expressionTable.Expressions;
foreach (Expression op in projectionExps) {
if (QueryProcessor.GetAsVariableRef(op) == null) {
notNotUpdatableReason = "Not updatable, result set contains functional " +
"projections. Please simplify the select terms.";
break;
}
}
// Otherwise, if it all looks ok, set the updatable table
if (notNotUpdatableReason == null) {
SystemTable nativeTableSource = transaction.GetTable(nativeTableName);
updatableView = new UpdatableResultSetView(transaction, nativeTableSource, projectionExps, backedTable.GetRowCursor());
}
} else {
notNotUpdatableReason = "This result set is not updatable.";
}
} else {
notNotUpdatableReason = "Not updatable, result set does not source " +
"to a native table.";
}
// If we didn't create an updatable view, we create one with null values
// and use if for iterator caching only
if (updatableView == null) {
updatableView = new UpdatableResultSetView(null, null, null, backedTable.GetRowCursor());
}
}
}
public void Close()
{
lock (syncObject) {
updatableView = null;
isClosed = true;
}
}
public RowIdResolver(UpdatableResultSetView resultView)
{
this.resultView = resultView;
}