The case of embedded SQL keywords in your programs is ignored. For example:

exec sql connect 
Exec Sql Connect

are all equivalent.

The case of cursor names, statement names and connection names must match that used when the variable is declared. For example, if you declare a cursor as C1, you must always refer to it as C1 (and not as c1).

The settings for the particular database determine whether such things as connection names, table and column names, are case-sensitive.

Hyphens are not permitted in SQL identifiers (in table and column names, for example).