The column module defines two classes, Column derived from DbSchemaObject and ColumnDict, derived from DbObjectDict.
Column is derived from ~pyrseas.dbobject.DbSchemaObject and represents a column of a table, or an attribute of a composite type. Its keylist attributes are the schema name and the table name.
A Column has the following attributes: name, type, not_null, default and collation. The number attribute is also present but is not made visible externally.
Class ColumnDict is a dictionary derived from ~pyrseas.dbobject.DbObjectDict and represents the collection of columns in a database, across multiple tables. It is indexed by the schema name and table name, and each value is a list of Column objects.