DBMS FUNCTIONS AND MODULES

  1. the data dictionnay called as well schema :

  2. optimization :

for the optimizer the input is a sql query and the output is an excution plan

the optimizer is component of the dbms .

the excution plan contains all the details about memory management of the db , using it the dbms excutes the query … now it is the OS TURN : the dbms gives the physical adress of the data which is stored in the meta data then the os fetches the data from the disk ( disk piste secteur offset ) using its adress

  1. multiuser acess control

  2. recovery

    EG : when a transaction fails in the middle , the query will be paused .