DBMS Notes Personal
DATA VS INFORMATION Data : a series of numbers like 9086526829. Information : This is Rita's ph no Problem with File Systems : 1. 2. no queries, so write a code for each functionality for each case/storyline 3. DBMS follows "Abstraction" priciple. different departments can see different part of data, but not all data. this is called as database view. 1. physical level/blueprint 3. view level - what end user sees T1 - everything in our local system app server - filter for currupt queries - it identifies harmful query and restrict its execution ER MODEL every entity has one unique id - primary key entity set - list of students Why ER diagram? - To help design the database and create table, it is a blueprint one customer can have multiple ph nos derived attribute : - age based on DOB strong entity : it has its own pk andidentifiable weak entity : depends on other, if no loan, no payment will be there, even t...