public static ReadOnlyCollection <NamedValueExpression> Gather(Expression expr)
{
var gatherer = new NamedValueGatherer();
gatherer.Visit(expr);
return(gatherer.namedValues.ToList().AsReadOnly());
}
private Expression ExecuteProjection(ProjectionExpression projection, bool okayToDefer)
{
// parameterize query
projection = (ProjectionExpression)Parameterize(projection);
if (scope != null)
{
// also convert references to outer alias to named values! these become SQL parameters too
projection = (ProjectionExpression)OuterParameterizer.Parameterize(scope.Alias, projection);
}
string commandText = linguist.Format(projection.Select);
ReadOnlyCollection <NamedValueExpression> namedValues = NamedValueGatherer.Gather(projection.Select);
var command = new QueryCommand(commandText, namedValues.Select(v => new QueryParameter(v.Name, v.Type, v.QueryType)));
Expression[] values = namedValues.Select(v => Expression.Convert(Visit(v.Value), typeof(object))).ToArray();
return(ExecuteProjection(projection, okayToDefer, command, values));
}
protected virtual Expression BuildExecuteCommand(CommandExpression command)
{
// parameterize query
Expression expression = Parameterize(command);
string commandText = linguist.Format(expression);
ReadOnlyCollection <NamedValueExpression> namedValues = NamedValueGatherer.Gather(expression);
var qc = new QueryCommand(commandText, namedValues.Select(v => new QueryParameter(v.Name, v.Type, v.QueryType)));
Expression[] values = namedValues.Select(v => Expression.Convert(Visit(v.Value), typeof(object))).ToArray();
ProjectionExpression projection = ProjectionFinder.FindProjection(expression);
if (projection != null)
{
return(ExecuteProjection(projection, false, qc, values));
}
Expression plan = Expression.Call(executor, "ExecuteCommand", null, Expression.Constant(qc), Expression.NewArrayInit(typeof(object), values));
return(plan);
}
protected virtual Expression BuildExecuteBatch(BatchExpression batch)
{
// parameterize query
Expression operation = Parameterize(batch.Operation.Body);
string commandText = linguist.Format(operation);
ReadOnlyCollection <NamedValueExpression> namedValues = NamedValueGatherer.Gather(operation);
var command = new QueryCommand(commandText, namedValues.Select(v => new QueryParameter(v.Name, v.Type, v.QueryType)));
Expression[] values = namedValues.Select(v => Expression.Convert(Visit(v.Value), typeof(object))).ToArray();
Expression paramSets = Expression.Call(typeof(Enumerable), "Select", new[] { batch.Operation.Parameters[1].Type, typeof(object[]) }, batch.Input,
Expression.Lambda(Expression.NewArrayInit(typeof(object), values), new[] { batch.Operation.Parameters[1] }));
Expression plan = null;
ProjectionExpression projection = ProjectionFinder.FindProjection(operation);
if (projection != null)
{
Scope saveScope = scope;
ParameterExpression reader = Expression.Parameter(typeof(FieldReader), "r" + nReaders++);
scope = new Scope(scope, reader, projection.Select.Alias, projection.Select.Columns);
LambdaExpression projector = Expression.Lambda(Visit(projection.Projector), reader);
scope = saveScope;
EntryMapping entity = EntityFinder.Find(projection.Projector);
command = new QueryCommand(command.CommandText, command.Parameters);
plan = Expression.Call(executor, "ExecuteBatch", new[] { projector.Body.Type }, Expression.Constant(command), paramSets, projector, Expression.Constant(entity, typeof(EntryMapping)),
batch.BatchSize, batch.Stream);
}
else
{
plan = Expression.Call(executor, "ExecuteBatch", null, Expression.Constant(command), paramSets, batch.BatchSize, batch.Stream);
}
return(plan);
}
