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Views in relational algebra:
1. Basic expression contains either
a) A relation in the database.
b) A constant relation.
2. General expressions are madde out of smaller sub expressions using
a) σp(E1) select (p a predicate)
b) ∏s(E1) project (s a list of attributes)
c) Px(E1)rename (x a relation name)
d) E1∪E2 union
e) E1- E2 set difference
f) E1x x E2 cartesian product
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What is D command work in the respect of QBE? D: It is the command inside QBE to delete tuple(s) from the relation.
What is a checkpoint? List the operations to be performed by the system when a checkpoint is to be taken. What does the recovery system do if there is a crash? There is large n
I have a homework assignment due today by midnight. I need help understanding databasse normalization and determining the type of form violation & how to fix the violation.
E-R model uses this symbol to represent weak entity set ? A Doubly outlined rectangle symbol is used to represent weak entity set.
Introduction In large projects, we can have many different companies working together. Generally, the project or contract is awarded to one company (Principal Contractor), which
Define the Immediate Update The immediate update methods may apply changes to the database on disk before the transaction arrives a successful conclusion. Though, these change
List some instances of collection types? a) sets b) arrays c) multisets
Hello.I have database access assignment which consist of creation Form, Subform, Calculation, Macros
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