internal static IEnumerable <ColumnExpression> Gather(Expression expression)
{
var gatherer = new ColumnGatherer();
gatherer.Visit(expression);
return(gatherer.columns.Values);
}
protected virtual Expression BuildExecuteBatch(BatchExpression batch)
{
// parameterize query
Expression operation = this.Parameterize(batch.Operation.Body);
string commandText = this.mapping.Language.Format(operation);
var namedValues = NamedValueGatherer.Gather(operation);
QueryCommand command = new QueryCommand(commandText, namedValues.Select(v => new QueryParameter(v.Name, v.Type, v.DbType)), null);
Expression[] values = namedValues.Select(v => Expression.Convert(this.Visit(v.Value), typeof(object))).ToArray();
Expression paramSets = Expression.Call(typeof(Enumerable), "Select", new Type[] { batch.Operation.Parameters[1].Type, typeof(object[]) },
batch.Input,
Expression.Lambda(Expression.NewArrayInit(typeof(object), values), new[] { batch.Operation.Parameters[1] })
);
Expression plan = null;
DbProjectionExpression projection = ProjectionFinder.FindProjection(operation);
if (projection != null)
{
var saveScope = this.scope;
ParameterExpression reader = Expression.Parameter(typeof(IDataReader), "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 columns = ColumnGatherer.Gather(projection.Projector);
command = new QueryCommand(command.CommandText, command.Parameters, columns);
plan = Expression.Call(this.provider, "ExecuteBatch", new Type[] { projector.Body.Type },
Expression.Constant(command),
paramSets,
projector,
batch.Size,
batch.Stream
);
}
else
{
plan = Expression.Call(this.provider, "ExecuteBatch", null,
Expression.Constant(command),
paramSets,
batch.Size,
batch.Stream
);
}
return(plan);
}
protected override Expression VisitMarker(MarkerExpression expression)
{
var target = expression.Target;
var processedTarget = Visit(target);
if (expression.MarkerType != MarkerType.None && (expression.MarkerType & MarkerType.Default) == MarkerType.None)
{
if (itemMaterializationContextParameter == null)
{
return(processedTarget);
}
var columns = ColumnGatherer.GetColumns(target, ColumnExtractionModes.Distinct | ColumnExtractionModes.Ordered).ToArray();
var sequenceCheck = Expression.Call(MaterializationHelper.IsNullMethodInfo, tupleParameter, Expression.Constant(columns));
var throwException = Expression.Convert(Expression.Call(MaterializationHelper.ThrowEmptySequenceExceptionMethodInfo), target.Type);
return(Expression.Condition(sequenceCheck, throwException, processedTarget));
}
return(processedTarget);
}
public List <Pair <int, Expression> > GetColumnsAndExpressions(ColumnExtractionModes columnExtractionModes)
{
return(ColumnGatherer.GetColumnsAndExpressions(Item, columnExtractionModes));
}
public List <int> GetColumns(ColumnExtractionModes columnExtractionModes)
{
return(ColumnGatherer.GetColumns(Item, columnExtractionModes));
}
public List <int> GetColumns(ColumnExtractionModes columnExtractionModes) => ColumnGatherer.GetColumns(Item, columnExtractionModes);
internal static IEnumerable<ColumnExpression> Gather(Expression expression)
{
var gatherer = new ColumnGatherer();
gatherer.Visit(expression);
return gatherer.columns.Values;
}
