MC Which statement is NOT CORRECT? Stored procedures may help to reduce network traffic. incorrect Using triggers may lead to deadlock situations. incorrect Triggers always help to enhance maintainability and performance. correct A disadvantage in using triggers is that they may cause cascade effects. incorrect
MC Suppose we have the following type definitions
CREATE TYPE STUDENTTYPE AS
(SNR SMALLINT NOT NULL,
SNAME CHAR(25) NOT NULL
MARK SMALLINT NOT NULL)
CREATE TYPE PHD-STUDENTTYPE AS (SCHOLARSHIP BOOLEAN NOT NULL)
UNDER STUDENTTYPE
We can now create the following two tables:
CREATE TABLE STUDENT OF TYPE STUDENTTYPE PRIMARY KEY (SNR)
CREATE TABLE PHD-STUDENT OF TYPE PHD-STUDENTTYPE UNDER STUDENT
Let's now also define the following two functions:
CREATE FUNCTION PASSED (STUDENT S)
RETURNING MARK > 50%
CREATE FUNCTION PASSED (PHD-STUDENT P)
RETURNING MARK > 70%
Consider the following query:
SELECT SNR, SNAME, PASSED FROM STUDENT
Which statement is correct? This query will determine whether students are passed by verifying that their mark exceeds 70%. incorrect This query will determine whether students are passed by verifying that their mark exceeds 50%. incorrect This query will only return whether non-PhD students are passed. incorrect This is an example of polymorphism since the ODBMS will ensure that, depending upon the tuple, the right implementation of the function PASSED is used. correct
MC Which statement is CORRECT? Opaque data types in an ORDBMS are always based on existing SQL data types. incorrect In an ORDBMS, inheritance can be only be implemented on data type level and not on table type level. incorrect A sourced function in an ORDBMS is based on an existing SQL function. correct A list is indexed, ordered and does not allow for duplicates. incorrect
MC Given the following SQL code for the wine database.
CREATE TRIGGER ODEREDQUANTITY
AFTER INSERT ON po_line
FOR EACH ROW
WHEN (NEW.PRODNR IS NOT NULL)
UPDATE product
SET AVAILABLE_QUANTITY = AVAILABLE_QUANTITY - NEW.QUANTITY
WHERE PRODNR=NEW.PRODNR
Which statement is CORRECT? This is an example of a stored procedure. incorrect This code will always be executed before a new tuple is inserted in the po_line table. incorrect This code will update the available quantity of a certain product by subtracting its ordered quantity. correct This code has to be explicitly invoked by a user or application program. incorrect
MC Suppose we have the following type definitions
CREATE TYPE STUDENTTYPE AS
(SNR SMALLINT NOT NULL,
SNAME CHAR(25) NOT NULL
MARK SMALLINT NOT NULL)
CREATE TYPE PHD-STUDENTTYPE AS (SCHOLARSHIP BOOLEAN NOT NULL)
UNDER STUDENTTYPE
We can now create the following two tables:
CREATE TABLE STUDENT OF TYPE STUDENTTYPE PRIMARY KEY (SNR)
CREATE TABLE PHD-STUDENT OF TYPE PHD-STUDENTTYPE UNDER STUDENT
Let's now also define the following two functions:
CREATE FUNCTION PASSED (STUDENT S)
RETURNING MARK > 50%
CREATE FUNCTION PASSED (PHD-STUDENT P)
RETURNING MARK > 70%
Consider the following query:
SELECT SNR, SNAME, PASSED FROM STUDENT
Which statement is correct? This query will determine whether students are passed by verifying that their mark exceeds 50%. incorrect This is an example of polymorphism since the ODBMS will ensure that, depending upon the tuple, the right implementation of the function PASSED is used. correct This query will determine whether students are passed by verifying that their mark exceeds 70%. incorrect This query will only return whether non-PhD students are passed. incorrect
MC Which statement is NOT CORRECT? Triggers always help to enhance maintainability and performance. correct A disadvantage in using triggers is that they may cause cascade effects. incorrect Stored procedures may help to reduce network traffic. incorrect Using triggers may lead to deadlock situations. incorrect
MC The key difference between stored procedures and triggers is that: Stored procedures are more difficult to debug than triggers. incorrect Stored procedures are explicitly invoked whereas triggers are implicitly invoked. correct Stored procedures cannot have input variables whereas triggers can. incorrect Stored procedures are stored in the data catalog, whereas triggers are not. incorrect
MC Which statement is NOT CORRECT? Stored procedures may help to reduce network traffic. incorrect A disadvantage in using triggers is that they may cause cascade effects. incorrect Using triggers may lead to deadlock situations. incorrect Triggers always help to enhance maintainability and performance. correct
MC An ORDBMS will typically support inheritance... only at a tuple level incorrect only at table type level incorrect only at data type level incorrect both at data type and table type level correct
MC An ORDBMS will typically support inheritance... only at data type level incorrect only at table type level incorrect both at data type and table type level correct only at a tuple level incorrect