A database column. It knows the table to which it belongs, its name,
and other metadata. The id of a column is a string of the form
"table_name.column_name".
author: Jim Menard, jimm@io.com
Constructor.
Parameters: table - the table to which this column belongs Parameters: colName - the column name Parameters: type - the data types See Also:java.sql.DatabaseMetaData.getColumns