No special permissions are required to use tempdb, that is, to create temporary tables or to execute commands that may require storage space in the temporary database.
Create temporary tables either by preceding the table name in a create table statement with a pound sign (#) or by specifying the name prefix “tempdb..”.
Temporary tables created with a pound sign are accessible only by the current Adaptive Server session: users on other sessions cannot access them. These nonsharable, temporary tables are destroyed at the end of each session. The first 13 bytes of the table’s name, including the pound sign (#), must be unique. Adaptive Server assigns the names of such tables a 17-byte number suffix. (You can see the suffix when you query tempdb..sysobjects.)
Temporary tables created with the “tempdb..” prefix are stored in tempdb and can be shared among Adaptive Server sessions. Adaptive Server does not change the names of temporary tables created this way. The table exists either until you restart Adaptive Server or until its owner drops it using drop table.
System procedures work on temporary tables, but only if you use them from tempdb.
If a stored procedure creates temporary tables, the tables are dropped when the procedure exits. Temporary tables can also be dropped explicitly before a session ends.
WARNING! Do not create temporary tables with the “tempdb..” prefix from inside a stored procedure unless you intend to share those tables among other users and sessions.
Each time you restart Adaptive Server, it copies model to tempdb, which clears the database. Temporary tables are not recoverable.