Service Group Application Reference

Service Group Application Reference

The SSA-NAME3 "Key"

The SSA-NAME3 "Key"

A basic appreciation of the strength of SSA-NAME3 can be gained from this description of the characteristics of the SSA-NAME3 key.
The first process of the SSA-NAME3 algorithm is to "code" the name words. This coding is not dissimilar from other algorithms in that it is building a coded form for each word such that all relevant variations of the word will have the same code.
The distinction here is that SSA-NAME3’s coding step does not unduly truncate or compress the name before key generation.
The second process of the algorithm is to choose an optimum key generation technique so as to compress the set of name words into a 5-byte binary or 8-byte character key. This is the key which will be stored in a database index. In fact, in most cases, for a single name, SSA-NAME3 will generate multiple keys. Within an SSA-NAME3 key, a variety of techniques are used to maximize the retention of valuable matching data, while retaining a logical structure that supports the depth of search concept and also allows matching when names are missing or truncated to initials. This choice of compression techniques is dynamic at two levels:
  • Firstly, when SSA-NAME3 is customized, a sample file of user data is processed and is used to define the details of the set of compression algorithms for that specific population.
  • Secondly the actual key generated has a variable structure depending upon the relative nature of the name words in a specific name. This is established at usage time.
The third process of the Algorithm is to build the Search Table start and end key values for each depth of search. It is these start and end values which application programs use to drive the search and it is this mechanism that insulates the application program from the need to understand the complex variable structure of the actual key.
It is often counter productive for the designer of an application using SSA-NAME3 to understand the detail of the rules for the depth constructs or key constructs. These have been developed empirically and proven to be valuable and appropriate in use.

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