rbd Flashcards
(215 cards)
The SELECT statement is used to
fetching records from the database
The INSERT statement is used to
inserting records into the database
The DELETE statement is used to
deleting records from the database
The UPDATE statement is used to
updating records in the database
INDEX in the database speeds up
searching for records in the database
The COMMIT statement is used to
approving changes to the database
The ROLLBACK instruction is used to
Rolling back changes to the database
The GRANT instruction is used to
granting permissions in the database
The REVOKE instruction is used to
revoking permissions in the database
The ALTER TABLE statement is used to
table schema changes
What is the value of the expression Null=Null
is undefined
What is the value of the expression True OR Null
True
What is the value of the expression False OR Null
Null
What is the value of the expression False AND Null
False
What is the value of the expression True AND Null
Null
What is the value of the NOT Null expression
True
What will be the result of executing the statement SELECT * FROM Employees WHERE EmployeeID=EmployeeID OR EmployeeID=NULL, Emp’s report
What will be the result of executing the statement SELECT * FROM Emp WHERE EmployeeID=EmployeeID AND NULL=EmployeeID, empty relation
Relation R has an attribute a. What number can be the result of executing the statement SELECT Count() FROM R WHERE a=a, always as many as the cardinality of the relation R
Relation R has an attribute a. What number can be the result of executing the statement SELECT Count() FROM R WHERE a<a, always 0
An entity corresponds to in a relational database
table
A unique relationship corresponds to the following in a relational database
foreign key
An ambiguous relationship corresponds to the following in a relational database
table
An attribute in a relational database corresponds to
column in table