To add this constraint to our table we’ll need to depend on our trusty alter command again.What this means is that every record we insert into this table must have an email address and must have a friend id, and this coupling of data must not be repeated.Now we know the syntax, the rules and the conventions, let us produce the code needed to create the FRIEND_NAME table. There are other things we can do with the alter command. We talked about constraints in previous articles, and I told you how all tables should have a primary key to describe uniqueness.
The exams are administered by Pearson Vue an independent testing organization, with locations worldwide.This course introduces students to the fundamentals of SQL using Oracle Database 11g database technology.To learn whether and in what ways the columns of an inherently updatable view can be modified, query the USER_UPDATABLE_COLUMNS data dictionary view.The information displayed by this view is meaningful only for inherently updatable views.Notes on Updatable Views An updatable view is one you can use to insert, update, or delete base table rows.
You can create a view to be inherently updatable, or you can create an INSTEAD OF trigger on any view to make it updatable.Now, whenever possible, I will go very far out of my way to avoid a trigger.I have two primary reasons for avoiding triggers: Hopefully the first reason to avoid triggers, the maintenance headache, is fairly easy to see.In this course students learn the concepts of relational databases and the powerful SQL programming language.Our technologist looks at trigger maintenance and implementation challenges.Oracle Developer/Administrator Certified Associate program is a unique program combining the required courses to become an Oracle Certified Associate both as a Developer and as an Administrator.