static internal ProjectedColumns ProjectColumns(Expression projector, Alias newAlias, bool isGroupKey = false, bool selectTrivialColumns = false)
{
var candidates = DbExpressionNominator.Nominate(projector, out Expression newProj, isGroupKey: isGroupKey);
ColumnProjector cp = new ColumnProjector(candidates, newAlias, selectTrivialColumns);
Expression e = cp.Visit(newProj);
return(new ProjectedColumns(e, cp.generator.Columns.NotNull().ToReadOnly()));
}
static internal ProjectedColumns ProjectColumns(Expression projector, Alias newAlias, bool isGroupKey = false, bool selectTrivialColumns = false)
{
Expression newProj;
var candidates = DbExpressionNominator.Nominate(projector, out newProj, isGroupKey: isGroupKey);
ColumnProjector cp = new ColumnProjector
{
newAlias = newAlias,
candidates = candidates,
projectTrivialColumns = selectTrivialColumns
};
Expression e = cp.Visit(newProj);
return new ProjectedColumns(e, cp.generator.Columns.ToReadOnly());
}
protected internal override Expression VisitProjection(ProjectionExpression proj)
{
Expression projector;
SelectExpression select = proj.Select;
using (binder.SetCurrentSource(proj.Select))
projector = this.Visit(proj.Projector);
Alias alias = binder.aliasGenerator.NextSelectAlias();
ProjectedColumns pc = ColumnProjector.ProjectColumns(projector, alias);
projector = pc.Projector;
select = new SelectExpression(alias, false, null, pc.Columns, select, null, null, null, 0);
if (projector != proj.Projector)
{
return(new ProjectionExpression(select, projector, proj.UniqueFunction, proj.Type));
}
return(proj);
}