________ are rules added to a database to help ensure the data's validity
Fill in the blank(s) with correct word
integrity constraints
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Why is the file that is created in the following session unaffected by the umask value?
What will be an ideal response?
The ____ topologyconsists of running cable from one PC or file server to the next, like links in a chain.
A. star B. mesh C. ring D. bus
The most common type of relationship in Access is the ________ relationship
A) on-to-one B) many-to-many C) joined D) one-to-many
Consider the following schema, where the keys are underlined:
``` Employee(SSN, Name,Dept) Project(SSN,PID,Name,Budget) ``` The SSN attribute in Project is the Id of the employee working on the project, and PID is the Id of the project. There can be several employees per project, but the functional dependency PID ? Name,Budget holds (so the relation is not normalized). Consider the query ``` SELECT P.Budget, P.Name, E.Name FROM Employee E, Project P WHERE E.SSN = P.SSN AND P.Budget > 99 AND E.Name = ’John’ ORDER BY P.Budget ``` Assume the following statistical information: 1. 10,000 tuples in Employee relation 2. 20,000 tuples in Project relation 3. 40 tuples per page in each relation 4. 10-page bu?er 5. 1000 di?erent values for E.Name 6. The domain of Budget consists of integers in the range of 1 to 100 7. Indices – Employee relation On Name: Unclustered, hash On SSN: Clustered, 3-level B+ tree – Project relation On SSN: Unclustered, hash On Budget: Clustered, 2-level B+ tree a. Draw the fully pushed query tree. b. Find the “best” execution plan and the second-best plan. What is the cost of each? Explain how you arrived at your costs.