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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.
Create a query that spans both tables. Eliminate redundant fields. Modify the Query to select only those Customers that had service dates in October and November 2006.
Explain efficient algorithm that, provided edge-labeled graph G with distinguished vertex v0 and sequence s = σ1, σ2, ..., σk of characters from Σ, returns path in G which begins at v0.
Use the three-sphere model for systems management and brainstorm issues related to the change based on the business, technology, and organization spheres.
Explain how you will visually represent the data for the sales of the individual stores and for the time period shown. You want to show the change in sales for each store over time for the past three years.
Your job is to create a database management system for bike shop who ‘buys' and ‘sells' new and second-hand bikes, and also parts of bike. Bike is constructed with parts while part can be fitted to different bikes.
Create a data warehouse for electronics store chain. Chain has 20 stores in 5 cities. Each store has different sections comprising computers, DVDs, TVs, audio, home appliances etc.
Write down the SQL code in order to carrying out the following requests. Display all the data in each of the four tables. Do not display the foreign key columns.
Why are these so significant yet so frequently ignored by developers? Write the long term problems when these constraints are not implemented? "
Relational database is based on fact that data in one table can be tied, or related to data in another table. To do this, database utilizes various types of keys to form or define these relationships.
Pick one of the different types of SQL statements (data definition language, data manipulation language, or data control language). Describe how that type of statement is use.
We want to construct a database for a world-wide package delivery company. Define a set of relational schemas and identify primary and foreign keys. Try not to include redundant schemas.
Explain the information-gathering techniques and design methods you would suggest to use for project. Recognize the key factors that help ensure the information required for the project.
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