/// <summary>
/// Visists Join clause in case of join with local collection
/// </summary>
private void VisitJoinWithLocalCollectionClause(JoinClause joinClause)
{
var type = joinClause.InnerSequence.Type;
var itemType = EnumerableHelper.GetIEnumerableItemType(type);
var sqlTypeName = SqlTypes.GetSqlTypeName(itemType);
if (string.IsNullOrWhiteSpace(sqlTypeName))
{
throw new NotSupportedException("Not supported item type for Join with local collection: " + type.Name);
}
var isOuter = false;
var sequenceExpression = joinClause.InnerSequence;
object values;
var subQuery = sequenceExpression as SubQueryExpression;
if (subQuery != null)
{
isOuter = subQuery.QueryModel.ResultOperators.OfType <DefaultIfEmptyResultOperator>().Any();
sequenceExpression = subQuery.QueryModel.MainFromClause.FromExpression;
}
switch (sequenceExpression.NodeType)
{
case ExpressionType.Constant:
var constantValueType = ((ConstantExpression)sequenceExpression).Value.GetType();
if (constantValueType.IsGenericType)
{
isOuter = DefaultIfEmptyEnumeratorType == constantValueType.GetGenericTypeDefinition();
}
values = ExpressionWalker.EvaluateEnumerableValues(sequenceExpression);
break;
case ExpressionType.Parameter:
values = ExpressionWalker.EvaluateExpression <object>(sequenceExpression);
break;
default:
throw new NotSupportedException("Expression not supported for Join with local collection: "
+ sequenceExpression);
}
var tableAlias = _aliases.GetTableAlias(joinClause);
var fieldAlias = _aliases.GetFieldAlias(joinClause.InnerKeySelector);
_builder.AppendFormat("{0} join table ({1} {2} = ?) {3} on (",
isOuter ? "left outer" : "inner",
fieldAlias,
sqlTypeName,
tableAlias);
Parameters.Add(values);
}
protected override Expression VisitConditional(ConditionalExpression expression)
{
ResultBuilder.Append("casewhen(");
Visit(expression.Test);
// Explicit type specification is required when all arguments of CASEWHEN are parameters
ResultBuilder.Append(", cast(");
Visit(expression.IfTrue);
ResultBuilder.AppendFormat(" as {0}), ", SqlTypes.GetSqlTypeName(expression.Type) ?? "other");
Visit(expression.IfFalse);
ResultBuilder.Append(')');
return(expression);
}
