Tuesday, June 30, 2015

Structured Query Language Quiz

Relational model and Normalization Quiz


1. In a CREATE TABLE statement, each column/attribute must have a data type associated with it. TRUE / FALSE?
    TRUE
    FALSE

2. Referential integrity ensures that a value stored in the foreign key attribute matches a primary key attribute in the referred table. TRUE/FALSE?
    TRUE
    FALSE

3. A view is part of the external schema and is considered as an acceptable way to offer simpler tables with customized attribute names to the user. TRUE/FALSE?
    TRUE
    FALSE

4. A view can be referred to like a table in a SELECT. TRUE/FALSE?
    TRUE
    FALSE

5. Besides a shorthand reference to the table throughout the query, using an alias makes the query run much faster as a result. TRUE/FALSE?
    TRUE
    FALSE

6. Deleting from a view that is based on a natural join of its base tables is acceptable. TRUE/FALSE?
    TRUE
    FALSE

7. If both NOT NULL and UNIQUE integrity constraints are defined on an attribute, the designation implies that the attribute is a candidate key. TRUE/FALSE?
    TRUE
    FALSE

8. An INSERT requires the input values sequence to match the attribute sequence when the attributes are specified in the INSERT statement. TRUE/FALSE?
    TRUE
    FALSE

9. The SQL SELECT statement includes the sequence of steps to exectue a query besides the operations that the server uses to answer the query. TRUE/FALSE?
    TRUE
    FALSE

10. Triggers provide a mechanism to monitor specific changes to a table and perform additional actions based on the altered data. TRUE/FALSE?
    TRUE
    FALSE

Score =

Correct answers:

Friday, June 26, 2015

Three levels in database system architecture quiz

Relational model and Normalization Quiz


1. The layout of the data within the disk file system is found at the logical/conceptual level. TRUE / FALSE?
    TRUE
    FALSE

2. There is exactly one schema at the conceptual level for a database. TRUE/FALSE?
    TRUE
    FALSE

3. There is exactly one schema at the external level of a database. TRUE/FALSE?
    TRUE
    FALSE

4. A user’s access to the database can be limited by the schema at the external level. TRUE/FALSE?
    TRUE
    FALSE

5. The indexing schemes for each table is found at the external level. TRUE/FALSE?
    TRUE
    FALSE

6. The mappings between the levels provides for program-data independence. TRUE/FALSE?
    TRUE
    FALSE

7. The mapping between the external and logical levels provides various views to the users. TRUE/FALSE?
    TRUE
    FALSE

8. The levels in the architecture in sequence is logical-external-physical. TRUE/FALSE?
    TRUE
    FALSE

9. A physical schema is typically derived from the logical schema. TRUE/FALSE?
    TRUE
    FALSE

10. An Entity-Relationship model will map most closely to the logical schema. TRUE/FALSE?
    TRUE
    FALSE

Score =

Correct answers:

Quiz on normalization and functional dependency 6

Relational model and Normalization Quiz


1. Functional dependency analysis helps in the normalization of a relational schema. TRUE / FALSE?
    TRUE
    FALSE

2. Normalization attempts to reduce redundant information that are stored as part of a relation. TRUE/FALSE?
    TRUE
    FALSE

3. Redundancy is at the root of insertion and deletion anomalies in a relational database. TRUE/FALSE?
    TRUE
    FALSE

4. A null value has exactly one interpretation, ie., one meaning. TRUE/FALSE?
    TRUE
    FALSE

5. A functional dependency is a relationship between an attribute "Y" and a determinant (1 or more other attributes) such that for a given value of a determinant the value of the attribute Y is uniquely defined. TRUE/FALSE?
    TRUE
    FALSE

6. Functional dependencies can be found out algorithmically (automatically) by analysis of the relation. No semantic analysis is required. TRUE/FALSE?
    TRUE
    FALSE

7. In practical terms, we want non-key attributes to be functionally dependent on the primary key in any relation. TRUE/FALSE?
    TRUE
    FALSE

8. Transitivity of functional dependencies means that if a →b and a→c then c→b. TRUE/FALSE?
    TRUE
    FALSE

9. Decomposition of functional dependencies would mean that if a→bc then a→b and a→c. TRUE/FALSE?
    TRUE
    FALSE

10. Functional dependencies are reflexive, i.e., if a →b then b →a. TRUE/FALSE?
    TRUE
    FALSE

Score =

Correct answers:

How does 2PC protocol handles failures in distributed database?

How does 2PC protocol handles failures in distributed database? / Handling participating site failure / Handling coordinator site failure / Handling network partition failure / How does Two Phase Commit protocol act to handle various failures in a distributed database?


Following are the failures that are possible in a distributed database environment. Clicking on the links that are given below will take you to the posts.