RE: Q. Whenever a DBA creates a user in which datafile...
It depends on the product you are using. For instance DB2 doesn't require that a user be defined (to DB2).
In a relational system it is only required that a relational catalog/data dictionary exists. What it looks like and how it's designed is up to the designers.
And please in a relational system data values are stored in TABLES not datafiles just tables.
RE: Whenever a DBA creates a user in which datafile th...
It depends how the user created While creating the user if a specific tablespaces is mentioned as the default tablespace then the user will be created in that tablespace's datafile. If no default tablespace is mentioned while creating the user then the users default tablespace will be "system" and all the object pertaining to that user will be created in the SYSTEM tablespace which will result in defragmentation with the lapse of time due to various DDL DML DCL and DTL statements. It always a good practice to assign a default tablespace for a user other than the SYSTEM tablespace.
RE: Whenever a DBA creates a user in which datafile that will be get created ?
When the user is created without mentioning default tablespace then it will be created in SYSTEM tablespace. If Temporary tablespace is also not mentioned then it will automatically take the default temporary tablespace mentioned by the DBA.
