[Back] [Up] [Next]

## Types of database correlations

A database correlation is a map that relates one or more databases. When there is more than one database involved in a database correlation, the time states from each database are related using a correlation method. Database correlations currently have 4 supported correlation methods: padded index, stretched index, time, and cycle. This section describes each of the correlation methods and when you might want to use each method.

For illustration purposes, the examples describing each correlation method use two databases, though database correlations can have any number of databases. The examples refer to the databases as: database A and database B. Both databases consist of a rectilinear grid with a material variable. The material variable is used to identify the database using a large letter A or B and also to visually indicate progress through the databases' numbers of time states by sweeping out a red material like a clock in reverse. At the first time state, there is no red material but as time progresses, the read material increases and finally totally replaces the material that was blue. Database A has 10 time states and database B has 20 time states. The tables below list the cycles and times for each time state in each database so the time and cycle behavior of database A and database B will make more sense later when time database correlations and cycle database correlations are covered.

Database A
Time state | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
Times | 14 | 14.5 | 15 | 15.5 | 16 | 16.5 | 17 | 17.5 | 18 | 18.5
Cycles | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9

Database B (part 1)
Time state | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
Times | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25
Cycles | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19

Database B (part 2)
Time state | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19
Times | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35
Cycles | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29