Creating and Using DataTables

A DataSet is made up of a collection of tables, relationships, and constraints. In ADO.NET, DataTable objects are used to represent the tables in a DataSet. A DataTable represents one table of in-memory relational data; the data is local to the .NET-based application in which it resides, but can be populated from a data source such as Microsoft® SQL Server using a DataAdapter For more information, see Populating a DataSet from a DataAdapter.

The DataTable class is a member of the System.Data namespace within the .NET Framework class library. You can create and use a DataTable independently or as a member of a DataSet, and DataTable objects can also be used in conjunction with other .NET Framework objects including the DataView. You access the collection of tables in a DataSet through the Tables property of the DataSet object.

The schema, or structure of a table is represented by columns and constraints. You define the schema of a DataTable using DataColumn objects as well as ForeignKeyConstraint and UniqueConstraint objects. The columns in a table can map to columns in a data source, contain calculated values from expressions, automatically increment their values, or contain primary key values.

In addition to a schema, a DataTable must also have rows in which to contain and order data. The DataRow class represents the actual data contained in a table. You use the DataRow and its properties and methods to retrieve, evaluate, and manipulate the data in a table. As you access and change the data within a row, the DataRow object maintains both its current and original state.

You can create parent-child relationships between tables using one or more related columns in the tables. You create a relationship between DataTable objects using a DataRelation. DataRelation objects can then be used to return the related child or parent rows of a particular row. For more information, see Adding a Relationship between Tables.

In This Section

• Creating a DataTable
  Explains how to create a DataTable and add it to a DataSet.
• Defining the Schema of a DataTable
  Provides information about creating and using DataColumn objects and constraints.
• Manipulating Data in a DataTable
  Explains how to add, modify, and delete data in a table. Explains how to use DataTable events to examine changes to data in the table.

Related Sections

• Accessing Data with ADO.NET
  Describes the ADO.NET architecture and components and how to use them to access existing data sources as well as to manage application data.
• Creating and Using DataSets
  Provides information about the ADO.NET DataSet including how to create relationships between tables.
• Constraint Class
  Provides reference information about the Constraint object.
• DataColumn Class
  Provides reference information about the DataColumn object.
• DataSet Class
  Provides reference information about the DataSet object.
• DataTable Class
  Provides reference information about the DataTable object.
• Introduction to the .NET Framework Class Library
  Provides an overview of the .NET Framework class library including the System namespace as well as its second-level namespace System.Data.