1. Read the following excerpt on ERM and fill in the blanks
2. Entity Relationship Modeling (ER Modeling) is a _______________________________. It uses Entity/Relationship to represent real world objects
3. An employee of an organization is an _________. If "Peter" is a
programmer (an employee) at Microsoft, he can have __________(properties)
like name, age, weight, height, etc. It is obvious that those do hold values
relevant to him.
4. In ER diagrams, rectangles are used to denote:
5. Entities can not have relationships with each other. They can only have relationships with properties
6. In Entity Relationship Modeling, we model entities, their attributes and relationships among entities.
7. In a university database we might have entities like:
8. Analyse the following 'Flight database' ER diagram. Which of the following statements is true?
9. Fill in the blanks for the third type of relationship
10. A database index allows a query to efficiently retrieve data from a database. Indexes are related to specific tables and consist of one or more _____-
11. Consider an index at the back of a book. The index entries consist of the ______________________________________
12. The attribute name could be structured as an attribute consisting of first name, middle initial, and last name. This type of attribute is called ______________
13. In the following example, 'Name' is a __________________ and 'Address' is a ___________________. The entity here is __________________.
14. The power of the index is that is allows you to more or less __________ access the book’s pages you’re interested in seeing. Practically speaking, this saves hours of page flipping
15. A table can never have more than one index built from it
16. The keys are a fancy term for the values we want to look up in the index. The keys are typically based on the tables’ _____
17. By comparing keys to the ______ it is possible to find one or more database records with the same value
18. Since an index drastically ___________ data retrieval, it is essential the correct indexes are defined for each table
19. Missing indexes may not be noticed for small databases, but once your tables _____________________________________________
20. Read through the following excerpt and fill in the blanks for the option that would help reduce the average flip and find time.
Consider that you have a deck of 52 cards: four suits,
Ace through King. If the deck is shuffled into random
order, and I asked you to pick out the 8 of hearts,
to do so you would individually flip through each card
until you found it.
On average you would have to go through half the deck,
which is 26 cards
You could seperate the cards into ________________
Now, to pick out the 8 of
hearts you would first select the hearts pile, which
would take on average two to find, and then flip through
13 cards. This is the power of an index. By segregating and sorting our
data on keys, we can use a piling method to drastically reduce
the number of flips it takes to find our data.
three piles -randomly shuffled
eight different piles, randomly shuffled
two piles by number (e.g. 1 to 9 and then Jack, Queen, King)
four piles by suit,
each pile randomly shuffled
21. The structure that is used to store a database index is called a___________. A __________ works similar to the card sorting strategy
22. In a B+ Tree the key values are separated into many smaller piles. As the name implies, the piles, technically called nodes, are connected in tree like fashion
23. An index is any data structure that _______________________________________
24. To find the Name for ID 13, an index on (ID) is useful, but the record must still be read to get the Name. However, an index on _____________ contains the required data field and eliminates the need to look up the record
25. Indexes are useful for slowing down data access and therefore making the search procedure more stable