May 2010
Intermediate to advanced
815 pages
21h 55m
English
book
SQL Server® 2008 Administration: Real World Skills for MCITP Certification and Beyond
by Tom Carpenter
Content preview from SQL Server® 2008 Administration: Real World Skills for MCITP Certification and BeyondBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
Start your free trial
Understanding Entity Relationship Diagramming
With the early stage business analysis complete, you're ready to move on to the actual modeling of the database. An entity relationship diagram (ERD) is a logical representation of your database that presents just such a model. An ERD is a logical model and may also be a physical model. A logical model is not system specific. Stated differently, the logical model is not unique to any specific database system, such as SQL Server or Oracle. The physical model specifies exactly how a logical model would be implemented within a specific system. You would need a different physical model for SQL Server than you would for Oracle.
You cannot store data in an ERD, nor can you retrieve data from an ERD. However, ...