public virtual ProjectionExpression AddOuterJoinTest(ProjectionExpression proj)
{
var test = this.GetOuterJoinTest(proj.Select);
var select = proj.Select;
FieldExpression testCol = null;
// look to see if test expression exists in fields already
foreach (var col in select.Fields)
{
if (test.Equals(col.Expression))
{
var colType = this.TypeSystem.GetStorageType(test.Type);
testCol = new FieldExpression(test.Type, colType, select.Alias, col.Name);
break;
}
}
if (testCol == null)
{
// add expression to projection
testCol = test as FieldExpression;
string colName = (testCol != null) ? testCol.Name : "Test";
colName = proj.Select.Fields.GetAvailableFieldName(colName);
var colType = this.TypeSystem.GetStorageType(test.Type);
select = select.AddField(new FieldDeclaration(colName, test, colType));
testCol = new FieldExpression(test.Type, colType, select.Alias, colName);
}
var newProjector = new OuterJoinedExpression(testCol, proj.Projector);
return new ProjectionExpression(select, newProjector, proj.Aggregator);
}
public static ProjectionExpression AddOuterJoinTest(this ProjectionExpression proj, QueryLanguage language, Expression expression)
{
string colName = proj.Select.Fields.GetAvailableFieldName("Test");
var colType = language.TypeSystem.GetStorageType(expression.Type);
SelectExpression newSource = proj.Select.AddField(new FieldDeclaration(colName, expression, colType));
Expression newProjector =
new OuterJoinedExpression(
new FieldExpression(expression.Type, colType, newSource.Alias, colName),
proj.Projector
);
return new ProjectionExpression(newSource, newProjector, proj.Aggregator);
}
protected virtual Expression VisitOuterJoined(OuterJoinedExpression outer)
{
var test = this.Visit(outer.Test);
var expression = this.Visit(outer.Expression);
return this.UpdateOuterJoined(outer, test, expression);
}
protected OuterJoinedExpression UpdateOuterJoined(OuterJoinedExpression outer, Expression test, Expression expression)
{
if (test != outer.Test || expression != outer.Expression)
{
return new OuterJoinedExpression(test, expression);
}
return outer;
}
protected virtual Expression VisitOuterJoined(OuterJoinedExpression outer)
{
this.Write("Outer(");
this.WriteLine(Indentation.Inner);
this.Visit(outer.Test);
this.Write(", ");
this.WriteLine(Indentation.Same);
this.Visit(outer.Expression);
this.WriteLine(Indentation.Outer);
this.Write(")");
return outer;
}
