• Logical database:
    • it  is a logical partition created in the physically installed db s/w
    • Each logical db can have tables and db users
    • If logical db allows multiple users and applications to access and manipulated the data then it is called multiple user db other wise it is called as single user db
    • Every logical db is identified with its unique name in oracle db s/w each logical db is identified with its SID(service id) value
    • When oracle db s/w is installed we will get one for default logical db
    • In ms-access db s/w each mdb(Microsoft db) files access as one logical db, so the mdb file will acts as logical db name.

  • Physical db s/w :The db s/w that are installed in our computer
  • In oracle db s/w each logical db name is nothing but SID (service id)
  • Processes to know default logical db Sid of oracle db s/w
    • There are three approaches to do this
                                           
  • Approach 1:


Approach 2 



  

Approach 3