private Expression ExecuteProjection(ProjectionExpression projection, bool okayToDefer, QueryCommand command, Expression[] values)
{
okayToDefer &= (this.receivingMember != null && this.policy.IsDeferLoaded(this.receivingMember));
var saveScope = this.scope;
ParameterExpression reader = Expression.Parameter(typeof(FieldReader), "r" + nReaders++);
this.scope = new Scope(this.scope, reader, projection.Select.Alias, projection.Select.Columns);
LambdaExpression projector = Expression.Lambda(this.Visit(projection.Projector), reader);
this.scope = saveScope;
var entity = EntityFinder.Find(projection.Projector);
string methExecute = okayToDefer
? "ExecuteDeferred"
: "Execute";
// call low-level execute directly on supplied DbQueryProvider
Expression result = Expression.Call(this.executor, methExecute, new Type[] { projector.Body.Type },
Expression.Constant(command),
projector,
Expression.Constant(entity, typeof(MappingEntity)),
Expression.NewArrayInit(typeof(object), values)
);
if (projection.Aggregator != null)
{
// apply aggregator
result = DbExpressionReplacer.Replace(projection.Aggregator.Body, projection.Aggregator.Parameters[0], result);
}
return(result);
}
public abstract int ExecuteCommand(QueryCommand query, object[] paramValues);
public abstract IEnumerable <T> ExecuteBatch <T>(QueryCommand query, IEnumerable <object[]> paramSets, Func <FieldReader, T> fnProjector, MappingEntity entity, int batchSize, bool stream);
public abstract IEnumerable <T> ExecuteDeferred <T>(QueryCommand query, Func <FieldReader, T> fnProjector, MappingEntity entity, object[] paramValues);
public abstract IEnumerable <int> ExecuteBatch(QueryCommand query, IEnumerable <object[]> paramSets, int batchSize, bool stream);