Does the SQL-1992 standard restrict naming identifiers to 18 characters?

In this draft of SQL:1992 , I found… Section 5.2 > Leveling Rules > > .... > > 2. The following restrictions apply for Entry SQL in addition to any Intermediate SQL restrictions: > a) No ` or **shall contain more than 18 `s**. …and… > Annex A.1 > 1. Subclause 5.2, "` and `": > a) In conforming Intermediate SQL language, a ` or a **shall not comprise more than 18 `s.** > b) A ` shall not be a or a `. > c) Conforming Intermediate SQL language shall contain no ` that ends in an `. ## For *implementors* of SQL, or for *users* of SQL? I searched the document multiple times, but could never get a sense of the meaning of identifier. - Is the spec referring to labeling within an *implementation* of SQL (such as PostreSQL or Oracle)? So labels used within the SQL product cannot contain identifiers that are over 18 characters or end in an underscore. - Or is the spec referring to *users* of a SQL implementation? So we who are naming our schemas, tables, columns, and other such database objects cannot use names over 18 characters or end in an underscore?