Comments
You can include C comments, delimited by /* and */ anywhere in an embedded SQL statement that a blank is allowed, with the following exceptions:
• Between the margin and the word exec (whether or not you have a C label prefix).
• Between the word exec and the word sql or frs. In the following example, comments cause both statements to be interpreted as C host code:
/* Initial comment */ exec sql include sqlca;
exec /* Between */ sql commit;
• Between words that are reserved when they appear together. For the list of double reserved words contained in the list of keywords, see the SQL Reference Guide.
• In string constants.
• In parts of statements that are dynamically defined. For example, a comment in a string variable specifying a form name is interpreted as part of the form name.
• Between component lines of embedded SQL/FORMS block‑type statements. All block‑type statements (such as activate and unloadtable) are compound statements that include a statement section delimited by begin and end. Comment lines must not appear between the statement and its section. The preprocessor interprets such comments as C host code, which causes preprocessor syntax errors. (However, comments can appear on the same line as the statement.)
For example, the following statement causes a syntax error on the C comment:
exec frs unloadtable empform
employee (:namevar = ename);
/* Illegal comment before statement body */
exec frs begin; /* Comment legal here */
strcat(msgbuf, namevar);
exec frs end;
• Between any components in a statement composed of more than one compound statement. An example of such a statement is the display statement, which typically consists of the display clause, an initialize section, activate sections, and a finalize section. C comments are translated as host code and cause syntax errors on subsequent statement components.
You can also use the SQL comment delimiter (‑-) to indicate that the rest of the line is a comment.
Example: Comment delimiter usage
exec sql delete --Delete all employees
from employee;
Last modified date: 08/28/2024