This section provides an overview of which changes are not permitted in the Schema DDL and the SSL at all or only with restrictions when records of a record type concerned are stored. BALTER issues warnings relating to these modifications in the analysis listing.
Compression
Compressed records cannot be processed by BALTER. BALTER abnormally terminates restructuring if you do not unload the record type before restructuring and if you:change the user or system part of the record type
change the structure of tables or hash areas which contain items of this record type as keys
Variable items
If records for a record type with a variable item are stored in the database, restrictions apply for restructuring. BALTER terminates restructuring abnormally in the following cases:An item of variable length is added
An item of variable length is removed
The maximum length of an item of variable length is changed
Lists
Record types stored in a single-level list must not be lengthened. A single-level list means ORDER IS LAST, FIRST, NEXT, PRIOR or IMMATERIAL and MODE IS LIST.Lists which cannot be distributed may not be relocated to other realms.
Distributable lists can be relocated as required. If only realms are added, the list remains unchanged and the restructuring process as a whole can be executed very quickly.
Cyclic set structures
If BALTER is to make a modification to all sets of a cyclic set structure (see "Cycle" in the "Design and Definition" manual), a modification in which the owner record type must be processed before the member record type, a deadlock situation will arise. Such modifications are either the creation of a new chain, or the additional linking of the member records to the appropriate owner record for sets in which the owner record type must be relocated in the course of further modifications.If modifications of this nature are planned for a cyclic set structure, restructuring must be split into two stages.