Defines column, column set, and index key structures.
The API has three key concepts: column, column set, and index key.
Column
A table in a database is defined by a set of columns. Each column has attributes such as a name, a type, and a maximum length (if text or binary).
A column definition is encapsulated by TDbCol.
Column set
A set of columns that describe a table are encapsulated in CDbColSet. The set can be iterated over using TDbColSetIter.
Index key
An index key orders one or more table columns (keys). It has attributes such as being unique or primary, a comparison specification for text columns, and a list of columns which make up the key.
The index key is encapsulated in CDbKey. A column for the key is encapsulated in TDbKeyCol.