/// <summary>
/// Substitutes names of remote tables with name of temporary tables
/// holding a cached version of remote tables.
/// </summary>
/// <remarks></remarks>
// TODO: This function call must be synchronized! ??
protected virtual void SubstituteRemoteTableNames(DatasetBase temporaryDataset, string temporarySchemaName)
{
switch (ExecutionMode)
{
case ExecutionMode.SingleServer:
// No remote table support
// Replace remote table references with temp table references
foreach (TableReference tr in SelectStatement.EnumerateSourceTableReferences(true))
{
if (!tr.IsSubquery && TemporaryTables.ContainsKey(tr.UniqueName))
{
throw new NotImplementedException();
}
}
break;
case ExecutionMode.Graywulf:
var sm = GetSchemaManager(false);
// Replace remote table references with temp table references
foreach (TableReference tr in SelectStatement.EnumerateSourceTableReferences(true))
{
SubstituteRemoteTableName(sm, tr, temporaryDataset, temporarySchemaName);
}
break;
default:
throw new NotImplementedException();
}
}
/// <summary>
/// Substitutes the name of a remote tables with name of the temporary table
/// holding a cached version of the remote data.
/// </summary>
/// <param name="sm"></param>
/// <param name="tr"></param>
/// <param name="temporaryDataset"></param>
/// <param name="temporarySchemaName"></param>
private void SubstituteRemoteTableName(SchemaManager sm, TableReference tr, DatasetBase temporaryDataset, string temporarySchemaName)
{
// Save unique name because it will change as names are substituted
var un = tr.UniqueName;
// TODO: write function to determine if a table is to be copied
// ie. the condition in the if clause of the following line
if (tr.IsCachable && TemporaryTables.ContainsKey(tr.UniqueName) &&
IsRemoteDataset(sm.Datasets[tr.DatasetName]))
{
tr.DatabaseName = temporaryDataset.DatabaseName;
tr.SchemaName = temporarySchemaName;
tr.DatabaseObjectName = TemporaryTables[un].TableName;
tr.DatabaseObject = null;
}
}
