Oracle7 Server Application Developer's Guide
Guidelines for Defining Labels
Labels and label formats vary from operating system to operating system. While your installation currently may not use more than one type of operating system, you should be aware of potential differences between labels and label formats in a distributed database configuration and for future porting considerations, particularly when writing applications that should be easily ported to other operating systems.
To promote portability between labels in databases from one operating system to another, you should consider the following guidelines when defining labels in your database.
Embedded Spaces and Punctuation
Be cautious when using embedded spaces and punctuation in labels, as not all operating systems can interpret them.
For example, a label of SENSITIVE:ALPHA/BETA may be correctly interpreted on one operating system, but not correctly interpreted by other operating systems.
Case Sensitivity
Use care when specifying labels using upper and lowercase, as some operating systems are case sensitive and some are not. You should avoid defining labels that are distinguished only by case (for those operating systems that are not case sensitive); in addition, you should avoid comparing labels for an exact string match, including case (for those operating systems that are).
For example, one operating system may interpret Truly_Sensitive and TRULY_SENSITIVE as different labels; however, an operating system that is not case sensitive would interpret them as identical.
Label Components
Because not all operating systems support the integrity, information, and installation-defined portions of a label, you should use care when defining these in Trusted Oracle or using them in applications.
Note that if you request a label component that is not supported by your operating system, Trusted Oracle will return a null value for that component.
Numeric Format
You should avoid using '0' to represent either a classification or a category in numeric format, as some operating systems begin numbering with '0' and some with '1'.
Number of Classifications and Categories
Be aware that the number of classifications and categories supported by operating systems differs. While most operating systems support between 16 and 256 hierarchical classifications, a few may fall above or below this range.