Domain Name and XID Field Restrictions
Note: Entering XIDs follow these same rules.
Note: Oracle does not recommend or support configurations that do not adhere to the parameters described below.
Follow these rules and recommendations when naming domains and entering data in XID fields:
- Domain names are recommended to be from 1 to 30 characters long.
- Domain names can contain only alphanumeric characters.
- Domain names can contain numbers and upper-case letters. The system automatically adds a forward slash (/).
- Domain names are not case sensitive.
- Domain names must begin with a letter (an alphabetic character).
- XID fields can contain numbers, upper-case letters of supported languages, spaces, underscores, and dashes.
- If your database character set contains multi-byte characters, Oracle RDBMS rules recommend that each name for a user or a role contain at least one single-byte character.
- Domain names cannot be an Oracle RDBMS reserved word.
- Depending on the Oracle product you plan to use to access a database object, names may be further restricted by other product-specific reserved words. For a list of a product's reserved words, see the manual for the specific product.
- Do not use the word DUAL as a name for an object or part. DUAL is the name of a dummy table.
- The Oracle SQL language contains other words that have special meanings. These words include datatypes, function names, and keywords (the uppercase words in SQL statements, such as DIMENSION, SEGMENT, ALLOCATE, DISABLE, and so forth). These words are not reserved; however, Oracle uses them internally. Therefore, if you use these words as names for objects and object parts, your SQL statements may be more difficult to read and may lead to unpredictable results.
- In particular, do not use words beginning with "SYS_" as schema object names, and do not use the names of SQL built-in functions for the names of schema objects or user-defined functions.
- INCLUDE PERIOD IN XID RESTRICTED CHARACTERS: If you use a period (.) in your XID pattern, you can disable this Optional Feature to use periods without restriction.
If this optional feature is enabled, you cannot use a period in an XID value. By default, this feature is enabled.
Note: To avoid potential system issues, it is strongly suggested that you do not disable this feature.