Q. Which of the following is not true about B+ trees?

View solution

Q. The extent of the database resource that is included with each lock is called the level of

View solution

Q. Snapshot isolation is a particular type of ______________ scheme.

View solution

Q. Snapshot isolation is used to give

View solution

Q. Lost update problem is

View solution

Q. Under first updater wins the system uses a __________ mechanism that applies only to updates.

View solution

Q. When a transaction Ti attempts to update a data item, it requests a _________ on that data item.

View solution

Q. Each of a pair of transactions has read data that is written by the other, but there is no data written by both transactions, is referred to as

View solution

Q. An application developer can guard against certain snapshot anomalies by appending a ______ clause to the SQL select query.

View solution

Q. Evaluate the CREATE TABLE statement:

CREATE TABLE products
(product_id NUMBER(6) CONSTRAINT prod_id_pk PRIMARY KEY, product_name VARCHAR2(15));

Which statement is true regarding the PROD_ID_PK constraint?

View solution

Q. Evaluate the following CREATE SEQUENCE statement:

CREATE SEQUENCE seq1
START WITH 100
INCREMENT BY 10
MAXVALUE 200
CYCLE
NOCACHE;

The sequence SEQ1 has generated numbers up to the maximum limit of 200. You issue the following SQL statement:

SELECT seq1.nextval FROM dual;

What is displayed by the SELECT statement?

View solution

Q. The method of access that uses key transformation is called as

View solution

Q. Why do we need concurrency control on B+ trees ?

View solution

Q. How many techniques are available to control concurrency on B+ trees?

View solution

Q. In crabbing protocol locking

View solution

Q. The deadlock can be handled by

View solution

Q. In crabbing protocol the the lock obtained on the root node is in _________ mode.

View solution

Q. If needed to split a node or coalesce it with its siblings, or redistribute key values between siblings, the crabbing protocol locks the parent of the node in ____________ mode.

View solution

Q. In crabbing protocol to inset or delete a key value the leaf node has to be locked in ___________ mode.

View solution

Q. B-link tree requires a pointer to its __________ sibling.

View solution