Data Wise Business Solutions

Defaults

A default value is used by the database engine when a value of a column is NULL.    Please see another article on the subject of not using NULLS:   Real World Use of NULLs

For number data type,  It is a must to define an unknown value as zero.  

Simple Name:  <Table Name> + Default + sequence
Example:  OrderDetailDefault1,  OrderDetailDefault2

Alternate Name: <Table Name> + df + sequence
Example:  OrderDetailDf1,  OrderDetailDf2 or OrderDetail_df3

Defaults are typically defined while the table/column is being created.

CREATE TABLE OrderDetail (
   OrderDetailID int not null,
   …
   Amount real default 0
   …
);