Extended Functions of ASF › Creating Indexes › Additional Index Keys

Additional Index Keys

The Additional Keys portion of the Extended Key Definition screen gives you more flexibility in your key definitions. You can define additional keys with the following options:

• Duplicates last, first, or not allowed
• Index sort order either ascending or descending

Concatenated Keys

Additional keys can consist of one column or more than one column. Keys that consist of more than one column are concatenated keys. When defining a concatenated key, you specify the order in which the columns are to be combined, as shown below:

NAME                      2
ADDRESS
CITY/ST/ZIP
TELEPHONE                 1

Each additional key is identified by the key number under which it is defined. The key number can be used to specify the storage sequence and display sequence of the table.

Defining Additional Keys

To define an additional key:

• In the Duplicates field, accept the default value LAS (duplicates last), or enter FIR (first) to store duplicates first or NO to specify that duplicates are not allowed.
• In the Ascending field, accept the default value YES to have the order ascending, or enter NO to make the order descending.
• Under the Column Order heading, number the columns that make up the key in the order that you want them concatenated. If the key consists of only one column, enter a field order of 1 for that column.

Unique Keys are Additional Keys

When a unique key is specified on the Column Definition screen, it displays as an additional key on the Extended Key Definition screen. If the unique key consists of more than one column, the Column Order is the order in which the columns are defined. You can modify the definition of the unique key on the Extended Key Definition screen if desired.