ADO.NET Cookbook

Chapter 3. Searching and Analyzing Data

Introduction

This chapter focuses on searching for records in views and tables, calculating values based on values in the same or other tables, and navigating data relations between tables.

The DataView is a data-bindable view of a DataTable that presents data with different sort orders and filters. You can create multiple views for each table; every table has a default data view. The DataViewManager class helps to manage the default data views for tables in a DataSet. Recipe 3.1 demonstrates how to use the DataView and DataViewManager class to filter and sort data in a DataSet. Recipe 3.12 shows how to filter a data view for rows that have null values.

The DataRelation class creates a parent/child relation between two tables in a DataSet. The DataRelation maintains referential integrity and you can use it to cascade updates and deletes. It can also be used to navigate between the tables. Recipe 3.4 shows how to use the data relation to get the parent row and the child rows for any row.

The DataTable and DataView classes both provide several ways to locate records from specified criteria. Searching an existing table or view saves a roundtrip to the database server. Although the DataView is created from a DataTable, searching is done differently in each. Recipe 3.8 shows how to find rows in a DataTable while Recipe 3.9 shows how to find rows in a DataView. You can create a DataView from a typed DataSet to search or filter. Recipe 3.11 shows how ...