Adaptive Server 15.0 introduces expanded limits for delimited identifiers
There are new limits for the length of object names or identifiers: 255 bytes for regular identifiers, and 253 bytes for delimited identifiers. The new limit applies to most user-defined identifiers including table name, column name, index name and so on. Due to the expanded limits, some system tables (catalogs) and built-in functions have been expanded.
For variables, “@” count as 1 byte, and the allowed name for the variable i 254 bytes.