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Database Systems
1. List the ACID properties. Explain the usefulness of each.
2. Consider the following two transactions: T13: read(A);read(B);if A = 0 then B := B + 1;write(B).T14: read(B);read(A);if B = 0 then A := A + 1;write(A).Let the consistency requirement be A = 0 or B = 0, with A = 0 and B = 0 as the initial values.a. Show that every serial execution involving these two transactions preserves the consistency of the database.b. Show a concurrent execution of T13 and T14 that produces a nonserializable schedule.c. Is there a concurrent execution of T13 and T14 that produces a serializable schedule?
3. What is the two-phase locking protocol? What is the strict two-phase locking protocol? What is the rigorous two-phase locking protocol? What benefit does strict two-phase locking protocol provide? What benefit does rigorous two-phase locking protocol provide?
4. Consider the log in Figure. Suppose there is a crash just before the <T0 abort> log record is written out. Explain what would happen during recovery.
Consider the relational database described in Problem Give expressions in tuple relational calculus and domain relational calculus for each of the following queries: Find all the companies that have offices in all the cities in which company C2..
Database Modeling and Design: A complete table diagram. Transform model to tables, include all attributes and keys.
Evaluate the success WellCo and PharmaCARE shareholders
Consider relation schema r(A,B,C,D,E, F) and a set of functional dependencies {A BCD,BCDE,BD,DA}. Calculate canonical cover for set of functional dependencies (show each step of your derivation with an explanation).
Journal entries have to be reconciled with the spreadsheet on a daily basis - Prepare a context diagram for the system and also prepare a diagram 0 DFD for the system
Suppose a database has tables given below. Write the names and e-mail addresses for all customers who have had stove repair which cost more than $50.
MCIS 630 Database Systems: - Write a recursive SQL query that outputs the names of all subparts of the part with part-id “P- 100”.
Write down the complete transaction using SQL.
Suppose you have a table which contains 27,000 data records, and you have unclustered B+ Tree Index on the table.
Find the entities from the functional requirements. Entities can come from Nouns in the text, they may also come from forms, reports and legacy code.
What is the key value of the 4th index record on the top level, assuming each index record points to the record with the highest key value in a block of the next level down?
Create a database from scratch that contains, at a minimum, the elements listed below
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