private List <List <string> > SelectWithIndexWhere(string indexName, string tableName)
{
try
{
var records = new List <List <string> >();
// only returns the names of the columns in the index, discarding the other parts of the index name (INDEX_<TableName>_....)
var columnsIndex = indexName.Split('_').Where(elem => elem != "Index" && !tableName.Contains(elem)).ToList();
if (columnsIndex.Count == 1)
{
FilterDefinition <BsonDocument> filter = Builders <BsonDocument> .Filter.Empty;
foreach (var condition in WhereConditionsList.Find(elem => elem.Key == tableName).Value)
{
var conditionSplit = condition.Item2.Split(' ');
switch (conditionSplit[0])
{
case "=":
{
filter &= Builders <BsonDocument> .Filter.Eq("_id", conditionSplit[1]);
}
break;
case "<":
{
filter &= Builders <BsonDocument> .Filter.Lt("_id", conditionSplit[1]);
}
break;
case ">":
{
filter &= Builders <BsonDocument> .Filter.Gt("_id", conditionSplit[1]);
}
break;
case "<=":
{
filter &= Builders <BsonDocument> .Filter.Lte("_id", conditionSplit[1]);
}
break;
case ">=":
{
filter &= Builders <BsonDocument> .Filter.Gte("_id", conditionSplit[1]);
}
break;
case "<>":
{
filter &= Builders <BsonDocument> .Filter.Ne("_id", conditionSplit[1]);
}
break;
case "!=":
{
filter &= Builders <BsonDocument> .Filter.Ne("_id", conditionSplit[1]);
}
break;
}
}
var keyValuePairs = MongoDB.GetCollectionFilteredByKey(indexName, filter);
foreach (var keyValue in keyValuePairs)
{
// if we use an index file for reading data, only the value needs to be kept, for key-lookup
var keys = keyValue.GetElement("value").Value.ToString().Split('#').ToList();
records.AddRange(PerformKeyLookup(keys, tableName));
}
}
return(records);
}
catch (Exception ex)
{
throw ex;
}
}
private List <string> SelectWithIndexWhere(string indexName, bool pkFlag)
{
try
{
var records = new List <string>();
// only returns the names of the columns in the index, discarding the other parts of the index name (INDEX_<TableName>_....)
var columnsIndex = indexName.Split('_').Where(elem => elem != "Index" && !TableName.Contains(elem)).ToList();
if (columnsIndex.Count == 1 || pkFlag == true)
{
// single-attribute index or selecting using a primary key condition
FilterDefinition <BsonDocument> filter = Builders <BsonDocument> .Filter.Empty;
foreach (var condition in WhereConditionsList)
{
var conditionSplit = condition.Item2.Split(' ');
switch (conditionSplit[0])
{
case "=":
{
filter &= Builders <BsonDocument> .Filter.Eq("_id", conditionSplit[1]);
}
break;
case "<":
{
filter &= Builders <BsonDocument> .Filter.Lt("_id", conditionSplit[1]);
}
break;
case ">":
{
filter &= Builders <BsonDocument> .Filter.Gt("_id", conditionSplit[1]);
}
break;
case "<=":
{
filter &= Builders <BsonDocument> .Filter.Lte("_id", conditionSplit[1]);
}
break;
case ">=":
{
filter &= Builders <BsonDocument> .Filter.Gte("_id", conditionSplit[1]);
}
break;
case "<>":
{
filter &= Builders <BsonDocument> .Filter.Ne("_id", conditionSplit[1]);
}
break;
case "!=":
{
filter &= Builders <BsonDocument> .Filter.Ne("_id", conditionSplit[1]);
}
break;
}
}
var keyValuePairs = MongoDB.GetCollectionFilteredByKey(indexName, filter);
foreach (var keyValue in keyValuePairs)
{
if (pkFlag == true)
{
records.Add(keyValue.GetElement("_id").Value + "#" + keyValue.GetElement("value").Value);
}
else
{
// if we use an index file for reading data, only the value needs to be kept, for key-lookup
records.Add(keyValue.GetElement("value").Value.ToString());
}
}
}
else
{
// multi-attribute index => needs separate filtering
var unfilteredRecords = MongoDB.GetEntireCollection(indexName);
var groupedConditions = new List <KeyValuePair <string, List <string> > >();
foreach (var condition in WhereConditionsList)
{
if (groupedConditions.Find(elem => elem.Key == condition.Item1.Item2).Value == null)
{
groupedConditions.Add(new KeyValuePair <string, List <string> >(condition.Item1.Item2, new List <string>()));
}
groupedConditions.Find(elem => elem.Key == condition.Item1.Item2).Value.Add(condition.Item2);
}
foreach (var indexRecord in unfilteredRecords)
{
var indRec = indexRecord.GetElement("_id").Value + "#" + indexRecord.GetElement("value").Value;
if (RecordKeyMatchesCondition(indRec, groupedConditions))
{
if (pkFlag == true)
{
records.Add(indexRecord.GetElement("_id").Value + "#" + indexRecord.GetElement("value").Value);
}
else
{
// if we use an index file for reading data, only the value needs to be kept, for key-lookup
records.Add(indexRecord.GetElement("value").Value.ToString());
}
}
}
}
return(records);
}
catch (Exception ex)
{
throw ex;
}
}
