BMGT 402 Lecture Notes - Lecture 11: Data Definition Language, Aggregate Function, Branch Table

• School: University of Maryland
• Department: Business and Management
• Course: BMGT 402
• Professor: Woei- Jyh Lee

Document Summary

View restrictions: sql imposes several restrictions on creation and use of views. If a column in view is based on an aggregate function: Column may appear only in select and order by clauses of queries that access view. Column may not be used in where nor be an argument to an aggregate function in any query based on view. Grouped view may never be joined with a base table or a view: following queries would fail. You"d need to count again for staff no and branch no for this to work. This would only give you the column one row of the branch number, staff number and count where row is 2. If we tried to insert the following tuple into staffpropcnt: Rejected you don"t know which properties that they are or what the primary keys are: another example. Rejected null is not allowed for many columns in.