protected override Statement Prepare(IQueryContext context)
{
var selectStatement = new SelectStatement {
SelectExpression = SelectExpression,
OrderBy = OrderBy
};
// check to see if the construct is the special one for
// selecting the latest IDENTITY value from a table
if (IsIdentitySelect(selectStatement.SelectExpression))
{
selectStatement.SelectExpression.Columns.RemoveAt(0);
FromTable fromTable = ((IList <FromTable>)selectStatement.SelectExpression.From.AllTables)[0];
var idExp = Expression.FunctionCall("identity", Expression.Constant(DataObject.String(fromTable.Name.ToString())));
selectStatement.SelectExpression.Columns.Add(new SelectColumn(idExp));
}
if (selectStatement.SelectExpression.Into != null)
{
selectStatement.intoClause = selectStatement.SelectExpression.Into;
}
// Generate the TableExpressionFromSet hierarchy for the expression,
TableExpressionFromSet fromSet = Planner.GenerateFromSet(selectStatement.SelectExpression, context.Connection);
// Form the plan
selectStatement.Plan = Planner.FormQueryPlan(context.Connection, selectStatement.SelectExpression, fromSet, selectStatement.OrderBy);
return(selectStatement);
}
protected override DataObject OnEvaluate(IExpressionEvaluator evaluator)
{
// Generate the TableExpressionFromSet hierarchy for the expression,
TableExpressionFromSet fromSet = Planner.GenerateFromSet(SelectExpression, evaluator.Context.QueryContext.Connection);
// Form the plan
IQueryPlanNode plan = Planner.FormQueryPlan(evaluator.Context.QueryContext.Connection, SelectExpression, fromSet, new List <ByColumn>());
return(new DataObject(PrimitiveTypes.Query(), plan));
}