/// <summary>
/// Returns true if query returns any document. This method does not deserialize any document. Needs indexes on query expression
/// </summary>
public bool Exists(Query query)
{
if (query == null)
{
throw new ArgumentNullException("query");
}
var nodes = query.Run <T>(this);
// if query execute with index, just returns nodes
if (query.ExecuteMode == QueryExecuteMode.IndexSeek)
{
return(nodes.FirstOrDefault() != null);
}
// execute full scan
foreach (var node in nodes)
{
var dataBlock = this.Database.Data.Read(node.DataBlock, true);
var doc = BsonSerializer.Deserialize(dataBlock.Buffer).AsDocument;
if (query.ExecuteFullScan(doc, new IndexOptions()))
{
return(true);
}
}
return(false);
}
/// <summary>
/// Count documnets with a query. This method does not deserialize any document. Needs indexes on query expression
/// </summary>
public int Count(Query query)
{
if (query == null)
{
throw new ArgumentNullException("query");
}
var nodes = query.Run <T>(this);
// if query execute with index, just returns nodes
if (query.ExecuteMode == QueryExecuteMode.IndexSeek)
{
return(nodes.Count());
}
var count = 0;
// execute full scan
foreach (var node in nodes)
{
var dataBlock = this.Database.Data.Read(node.DataBlock, true);
var doc = BsonSerializer.Deserialize(dataBlock.Buffer).AsDocument;
if (query.ExecuteFullScan(doc))
{
count++;
}
}
return(count);
}
internal override bool ExecuteFullScan(BsonDocument doc, IndexOptions options)
{
return(_left.ExecuteFullScan(doc, options) && _right.ExecuteFullScan(doc, options));
}
/// <summary>
/// Find documents inside a collection using Query object. Must have indexes in query expression
/// </summary>
public IEnumerable <T> Find(Query query, int skip = 0, int limit = int.MaxValue)
{
if (query == null)
{
throw new ArgumentNullException("query");
}
var nodes = query.Run <T>(this);
// if query run on index, lets skip/take with linq-to-object
if (query.ExecuteMode == QueryExecuteMode.IndexSeek)
{
if (skip > 0)
{
nodes = nodes.Skip(skip);
}
if (limit != int.MaxValue)
{
nodes = nodes.Take(limit);
}
}
foreach (var node in nodes)
{
var dataBlock = this.Database.Data.Read(node.DataBlock, true);
var doc = BsonSerializer.Deserialize(dataBlock.Buffer).AsDocument;
// if need run in full scan, execute full scan and test return
if (query.ExecuteMode == QueryExecuteMode.FullScan)
{
// execute query condition here - if false, do not add on final results
if (query.ExecuteFullScan(doc, new IndexOptions()) == false)
{
continue;
}
// implement skip/limit before on full search - no linq
if (--skip >= 0)
{
continue;
}
if (--limit <= -1)
{
yield break;
}
}
// get object from BsonDocument
var obj = this.Database.Mapper.ToObject <T>(doc);
foreach (var action in _includes)
{
action(obj);
}
yield return(obj);
}
}
internal override bool ExecuteFullScan(BsonDocument doc)
{
return(_left.ExecuteFullScan(doc) && _right.ExecuteFullScan(doc));
}
