ER Diagram - View Intergration/Centralised approach Could anyone enlighten me on the difference between a view integration and centralised approach when designing a database, and how the ER diagram can be used to illustrate upon this; can't seem to find any simple explanations on the topic 


i understand ER diagrams
Centralized approach 

Requirements for each  user view are merged into a single list of requirements for the new database system. A logical data model representing all user views is created during the database design stage. The centralized approach involves collating the requirements for different user views into a single list of requirements. A data model representing all user views is created in the database design stage. 

view integration

Requirements for each user view remain as separate lists. Data models representing each user view are created and then merged later during the database design stage. The view integration approach involves leaving the requirements for each user view as separate lists of requirements. We create data models representing each user view. A data model that represents a single user view is called a local logical data model. We then merge the local data models to create a global logical data model representing all user views of the company