Types of access Schema DDL
102 U929-J-Z125-9-76
Generating an additional access path via secondary key
SEARCH KEY IS item-name,... USING INDEX [NAME IS name]
DUPLICATES ARE[ NOT] ALLOWED
A key defined by means of SEARCH-KEY IS... is called a SEARCH key or secondary key.
It may consist of more than one item.
item-name specifies the item(s) comprising the key. All items have to be part of the m ember.
name specifies the name of the table. This name is referred to in SSL statements concern ing
the table.
DUPLICATES ARE[ NOT] ALLOWED specifies whether UDS/SQL is to accept or reject
duplicate key values.
Based on this definition, UDS/SQL sets up a SEARCH key table on set level or a set
SEARCH key table for each set occurrence of the set. This table represents a unique
reference between secondary key value, database key value and physical address for each
record belonging to the set occurrence. It must be a multi-level table. When the position of
the record is changed, the physical address is not automaticall y updated.
Several independent secondary keys can be defined for each set.