Comments

Comments are allowed in the prolog or query body. Comments do not affect query processing.

A comment is composed of a string that is delimited by the symbols (:and :). The following example is a comment in XQuery:
(: A comment. You can use comments to make your code easier to understand. :)

The following general rules apply to using comments in Db2 XQuery:

  • Comments can be used wherever ignorable whitespace is allowed. Ignorable whitespace is whitespace that is not significant to the expression results.
  • Comments are not allowed in constructor content.
  • Comments can nest within each other, but each nested comment must have open and close delimiters, (: and :).

The following examples illustrate legal comments and comments that result in errors:

  • (: is this a comment? ::) is a legal comment.
  • (: is this a comment? ::) or an error? :) results in an error because there is an unbalanced nesting of the symbols (: and :).
  • (: commenting out a (: comment :) might be confusing, but is often helpful :) is a legal comment because a balanced nesting of comments is allowed.
  • "this is just a string :)" is a legal expression.
  • (: "this is just a string :)" :) results in an error. Likewise, "this is another string (:" is a legal expression, but (: "this is another string (:" :) results in an error. Literal content can result in an unbalanced nesting of comments.