private string CheckForIndex(List <KeyValuePair <string, List <Tuple <string, string> > > > conditionList, string tableName)
{
if (!conditionList.Any(elem => elem.Key == tableName))
{
return("");
}
var conditionsForTable = conditionList.Find(elem => elem.Key == tableName).Value;
var columnNames = "";
foreach (var column in conditionsForTable)
{
columnNames += column.Item1 + "_";
}
columnNames = columnNames.Remove(columnNames.Length - 1);
// check if any unique key index files can be used
var uniqueFiles = TableUtils.GetUniqueFiles(DatabaseName, tableName);
foreach (var unique in uniqueFiles)
{
if (unique.Contains(columnNames))
{
return(unique);
}
}
var searchedIndexName = "Index_" + tableName + "_" + columnNames;
var indexFiles = TableUtils.GetIndexFiles(DatabaseName, tableName);
foreach (var index in indexFiles)
{
if (index.IndexFileName.Contains(searchedIndexName))
{
// an index is used in the selection condition if the attributes are a prefix of the attributes in an existing index
return(index.IndexFileName);
}
}
return("");
}
private string CheckForIndex(List <Tuple <Tuple <string, string>, string> > conditionList, string tableName)
{
if (conditionList.Count == 0)
{
return("");
}
// build the index name containing the attributes from the condition
var columnNames = "";
foreach (var column in conditionList)
{
columnNames += column.Item1.Item2 + "_";
}
columnNames = columnNames.Remove(columnNames.Length - 1);
// check if any unique key index files can be used
var uniqueFiles = TableUtils.GetUniqueFiles(DatabaseName, tableName);
foreach (var unique in uniqueFiles)
{
if (unique.Contains(columnNames))
{
return(unique);
}
}
var searchedIndexName = "Index_" + tableName + "_" + columnNames;
var indexFiles = TableUtils.GetIndexFiles(DatabaseName, tableName);
foreach (var index in indexFiles)
{
if (index.IndexFileName.Contains(searchedIndexName))
{
// an index is used in the selection condition if the attributes are a prefix of the attributes in an existing index
return(index.IndexFileName);
}
}
return("");
}
