Identifiers

Identifiers are tokens used to form names. They fall into two categories:

• Ordinary Identifiers

  These must begin with a letter (A-z), and may include letters (including standard IBM code page extended characters), digits and the special characters #$%&{}. The maximum length of ordinary identifiers depends on the object they name, as shown below. See XDB Server Specifications for a complete list of identifier limits.

  Short Identifiers. These are up to 8 characters long. Examples are database names and AuthIDs.

  Long Identifiers. These are up to 18 characters long (except location names are up to 16 characters.) Examples are column and table names.

  Follow the character selection rules below when naming short or long identifiers:

  • The first character can be chosen only from the letters of the alphabet (A-z) if using XDB mode.
  • If using DB2 mode, the letters of the alphabet (A-z), the special characters @#$, and IBM Code Page extended characters can be chosen for the first character position.
  • All following characters can follow the rules for Ordinary Identifiers defined above (which apply equally to XDB mode and DB2 mode).
• Delimited Identifiers

  These consist of one or more characters enclosed within double (") or single quotes ('). A delimited identifier may contain either double quotes or apostrophes (or single quotes), in which case the identifier is usually delimited by the other type of quote. For example, the string Joe's Place can be used as a delimited identifier when written as:

  "Joe's Place"

  You can place both " and ' characters within the same string by using "" for " if you are using " as the string delimiter, or '' for ' if you are using ' as the string delimiter. For example, to enter the string value 5'11" into a character field, use a command like:

  UPDATE patient
  SET height='5''11"'
  WHERE name="o'HARA"