private static Expression BuildSqlCompatibleExpression(Expression expression, out IQueryable source)
{
bool pullIntoMemory = ShouldBePulledIntoMemory(expression);
var handleInProviderVisitor = new DataFacadeQueryableExpressionVisitor(pullIntoMemory);
var newExpression = handleInProviderVisitor.Visit(expression);
// Checking if the source contains queries both from SQL and Composite.Data.Caching.CachingQueryable in-memory queries.
// In this case, we can replace CachingQueryable instances with sql queries which allows building correct sql statements.
var analyzer = new QueryableAnalyzerVisitor();
analyzer.Visit(newExpression);
if (analyzer.CachedSqlQueries > 1 ||
(analyzer.SqlQueries > 0 && analyzer.CachedSqlQueries > 0))
{
newExpression = new CachedQueryExtractorVisitor().Visit(newExpression);
newExpression = handleInProviderVisitor.Visit(newExpression);
}
source = handleInProviderVisitor.Queryable;
return(newExpression);
}
public S Execute <S>(Expression expression)
{
bool pullIntoMemory = ShouldBePulledIntoMemory(expression);
var handleInProviderVisitor = new DataFacadeQueryableExpressionVisitor(pullIntoMemory);
Expression newExpression = handleInProviderVisitor.Visit(expression);
IQueryable source = handleInProviderVisitor.Queryable;
return((S)source.Provider.Execute(newExpression));
}
public IEnumerator <T> GetEnumerator()
{
if (object.Equals(_currentExpression, _initialExpression))
{
if (_sources.Count == 1 && _sources[0] is IEnumerable <T> )
{
return((_sources[0] as IEnumerable <T>).GetEnumerator());
}
if (_sources.Count == 0)
{
return(new List <T>().GetEnumerator());
}
}
bool pullIntoMemory = ShouldBePulledIntoMemory(_currentExpression);
var handleInProviderVisitor = new DataFacadeQueryableExpressionVisitor(pullIntoMemory);
Expression newExpression = handleInProviderVisitor.Visit(_currentExpression);
// Checking if the source contains queries both from SQL and Composite.Data.Caching.CachingQueryable in-memory queries.
// In this case, we can replace CachingQueryable instances with sql queries which allows building correct sql statements.
var analyzer = new QueryableAnalyzerVisitor();
analyzer.Visit(newExpression);
if (analyzer.CachedSqlQueries > 1 ||
(analyzer.SqlQueries > 0 && analyzer.CachedSqlQueries > 0))
{
newExpression = new CachedQueryExtractorVisitor().Visit(newExpression);
newExpression = handleInProviderVisitor.Visit(newExpression);
}
// Executing the query
IQueryable source = handleInProviderVisitor.Queryable;
IQueryable <T> queryable = (IQueryable <T>)source.Provider.CreateQuery(newExpression);
return(queryable.GetEnumerator());
}