DataTable.Select and Performance Issue in C#

Question

I\'m importing the data from three Tab delimited files in the DataTables and after that I need to go thru every row of master table and find all the rows in two child tables

Answer 1

If you create a DataRelation between your parent and child DataTables, you can look up child rows by invoking DataRow.GetChildRows(DataRelation) on the parent row (resp. DataRow.GetChildRelName in case of typed DataSets). The search will apply a TreeMap lookup, and performance should be fine even with a lot of child rows.

In case you have to search for rows based on other criteria than on a DataRelation's foreign keys, I recommend to use DataView.Sort / DataView.FindRows() instead of DataTable.Select(), as soon as you have to query the data more than once. DataView.FindRows() will be based on TreeMap lookup (O(log(N)), where as DataTable.Select() has to scan all rows (O(N)). This article contains more details: http://arnosoftwaredev.blogspot.com/2011/02/when-datatableselect-is-slow-use.html