The DataColumn class
defines the schema for a column in a DataTable.
This schema defines the type of data that can be stored in the
column, whether that data can be updated, any unique constraints on
the data, and how values should be generated for new rows added to
the table. Columns can be based on expressions that define a
calculation or an aggregation for a column value.
As with all disconnected data classes, the
DataColumn isn’t specific to any
data provider