/// <summary>
/// Find and flatten the prefix set of queries into a single query by substituting their expressions.
/// </summary>
/// <returns>The query that has been flatten</returns>
public QueryUnderConstruction FlattenAsPossible()
{
// Flatten should be done when the current query can be translated without the need of using sub query
// The cases that need to use sub query are:
// 1. Select clause appears after Distinct
// 2. There are any operations after Take
// 3. There are nested Select, Where or OrderBy
QueryUnderConstruction parentQuery = null;
QueryUnderConstruction flattenQuery = null;
bool seenSelect = false;
bool seenAnyOp = false;
for (QueryUnderConstruction query = this; query != null; query = query.inputQuery)
{
foreach (Binding binding in query.fromParameters.GetBindings())
{
if ((binding.ParameterDefinition != null) && (binding.ParameterDefinition is SqlSubqueryCollection))
{
flattenQuery = this;
break;
}
}
if (flattenQuery != null)
{
break;
}
if ((query.topSpec != null && seenAnyOp) ||
(query.selectClause != null && query.selectClause.HasDistinct && seenSelect))
{
parentQuery.inputQuery = query.FlattenAsPossible();
flattenQuery = this;
break;
}
seenSelect = seenSelect || ((query.selectClause != null) && !(query.selectClause.HasDistinct));
seenAnyOp = true;
parentQuery = query;
}
if (flattenQuery == null)
{
flattenQuery = this.Flatten();
}
return(flattenQuery);
}
/// <summary>
/// Find and flatten the prefix set of queries into a single query by substituting their expressions.
/// </summary>
/// <returns>The query that has been flatten</returns>
public QueryUnderConstruction FlattenAsPossible()
{
// Flatten should be done when the current query can be translated without the need of using sub query
// The cases that need to use sub query are:
// 1. Select clause appears after Distinct
// 2. There are any operations after Take that is not a pure Select.
// 3. There are nested Select, Where or OrderBy
QueryUnderConstruction parentQuery = null;
QueryUnderConstruction flattenQuery = null;
bool seenSelect = false;
bool seenAnyNonSelectOp = false;
for (QueryUnderConstruction query = this; query != null; query = query.inputQuery)
{
foreach (Binding binding in query.fromParameters.GetBindings())
{
if ((binding.ParameterDefinition != null) && (binding.ParameterDefinition is SqlSubqueryCollection))
{
flattenQuery = this;
break;
}
}
// In Select -> SelectMany cases, fromParameter substitution is not yet supported .
// Therefore these are un-flattenable.
if (query.inputQuery != null &&
(query.fromParameters.GetBindings().First().Parameter.Name == query.inputQuery.Alias.Name) &&
query.fromParameters.GetBindings().Any(b => b.ParameterDefinition != null))
{
flattenQuery = this;
break;
}
if (flattenQuery != null)
{
break;
}
if (((query.topSpec != null || query.offsetSpec != null || query.limitSpec != null) && seenAnyNonSelectOp) ||
(query.selectClause != null && query.selectClause.HasDistinct && seenSelect))
{
parentQuery.inputQuery = query.FlattenAsPossible();
flattenQuery = this;
break;
}
seenSelect = seenSelect || ((query.selectClause != null) && !(query.selectClause.HasDistinct));
seenAnyNonSelectOp |=
(query.whereClause != null) ||
(query.orderByClause != null) ||
(query.topSpec != null) ||
(query.offsetSpec != null) ||
(query.fromParameters.GetBindings().Any(b => b.ParameterDefinition != null)) ||
((query.selectClause != null) && ((query.selectClause.HasDistinct) || (this.HasSelectAggregate())));
parentQuery = query;
}
if (flattenQuery == null)
{
flattenQuery = this.Flatten();
}
return(flattenQuery);
}
