In addition to the the Commonwealth Ensign, there are three other official Australian ensigns: 1  The Australian Red Ensign - Merchant Navy, as for the Australian flag, but with a red field with white stars. 2  The Australian White Ensign - Royal Australian Navy - as for the Australian flag but with a white field and dark blue stars.
Null (or NULL) is a special marker used in Structured Query Language to indicate that a data value does not exist in the database. Introduced by the creator of the relational database model, E. F. Codd, SQL Null serves to fulfil the requirement that all true relational database management systems (RDBMS) support a representation of missing information and inapplicable information.
What is a NULL Value? A field with a NULL value is a field with no value. If a field in a table is optional, it is possible to insert a new record or update a record without adding a value to this field. Then, the field will be saved with a NULL value. Note: It is very important to understand that a NULL value is different from a zero value or a field that contains spaces. A field with a NULL value is one that has been left blank during record creation!