Understanding how data structure conflicts are resolved

The order in which application programs need to process fields and segments within hierarchies is frequently not the same for each application. When the DBA finds a conflict in the way that two or more programs need to access the data, three options are available to solve these problems. Each of the following options solves a different kind of conflict.

• When an application program does not need access to all the fields in a segment, or if the program needs to access them in a different order, the DBA can use field level sensitivity for that program. Field-level sensitivity makes it possible for an application program to access only a subset of the fields that a segment contains, or for an application program to process a segment's fields in an order that is different from their order in the segment.
• When an application program needs to access a particular segment by a field other than the segment's key field, the DBA can use a secondary index for that database.
• When the application program needs to relate segments from different hierarchies, the DBA can use logical relationships. Using logical relationships can give the application program a logical hierarchy that includes segments from several hierarchies.