// Executes the expression tree that is passed to it.
public object Execute(Expression expression, bool isEnumerable)
{
// The expression must represent a query over the data source.
if (!IsQueryOverDataSource(expression))
{
throw new InvalidProgramException("No query over the data source was specified.");
}
string whereClause = "";
// Find the call to Where() and get the lambda expression predicate.
var whereExpression = new InnermostWhereFinder().GetInnermostWhere(expression);
if (whereExpression != null)
{
var lambdaExpression = (LambdaExpression)((UnaryExpression)whereExpression.Arguments[1]).Operand;
// Send the lambda expression through the partial evaluator.
lambdaExpression = (LambdaExpression)Evaluator.PartialEval(lambdaExpression);
var builder = new FSWhereBuilder(lambdaExpression.Body);
whereClause = builder.WhereClause;
}
var queryableResult = _fsRep.Get(whereClause).AsQueryable();
return(isEnumerable
? queryableResult.Provider.CreateQuery(expression)
: queryableResult.Provider.Execute(expression));
}
/// <summary>
/// Executes the given <paramref name="queryModel" /> as a collection query, i.e. as a query returning objects of type
/// <typeparamref name="T" />.
/// The query does not end with a scalar result operator, but it can end with a single result operator, for example
/// <see cref="T:Remotion.Linq.Clauses.ResultOperators.SingleResultOperator" /> or
/// <see cref="T:Remotion.Linq.Clauses.ResultOperators.FirstResultOperator" />. In such a case, the returned enumerable
/// must yield exactly
/// one object (or none if the last result operator allows empty result sets).
/// </summary>
/// <typeparam name="T">The type of the items returned by the query.</typeparam>
/// <typeparam name="TFSEntity"></typeparam>
/// <param name="queryModel">
/// The <see cref="T:Remotion.Linq.QueryModel" /> representing the query to be executed. Analyze this via an
/// <see cref="T:Remotion.Linq.IQueryModelVisitor" />.
/// </param>
/// <returns>A scalar value of type <typeparamref name="TFSEntity" /> that represents the query's result.</returns>
public IEnumerable <T> ExecuteCollection <T>(QueryModel queryModel)
{
var command = FSQueryModelVisitor.GenerateFSQuery(queryModel);
if (_command != null)
{
var whereClause = command.WhereClause.HasValue() && _command.WhereClause.HasValue()
? command.WhereClause + " AND " + _command.WhereClause
: command.WhereClause.HasValue()
? command.WhereClause
: _command.WhereClause.HasValue()
? _command.WhereClause
: string.Empty;
var orderBy = _command.OrderByClause.HasValue()
? string.Join(",", _command.OrderByClause, command.OrderByClause).Trim(',')
: command.OrderByClause;
command = new FSCommand(
whereClause: whereClause,
orderByClause: orderBy,
offset: command.Offset ?? _command.Offset,
limit: command.Limit ?? _command.Limit
);
}
var fsQuery = _rep.Get(command.WhereClause, command.OrderByClause, command.Offset, command.Limit);
var projection = FSProjectionVisitor <TFSEntity, T> .BuildProjector(queryModel.SelectClause.Selector);
return(fsQuery.Select(projection));
}