Week 3

Question 1

Put these in order

establish connection
close connection
create statement and its query
execute the statement
process results & metadata

Answer 1

establish connection
create statement and its query
execute the statement
process results & metadata
close connection

Question 2

You import DriverManager into your class, getConnection() does what? What does it throw?

Answer 2

getConnection() creates instances of Connection, throws SQLException and SQLTimeoutException

Question 3

T/F - getConnection() can be overloaded

Answer 3

True

Question 4

What are the 3 String arguments used for getConnection?

Answer 4

Connection string (like a url), userid, password

note: connection string can specify options

Question 5

jdbc:mysql
jdbc:oracle
jdbc:db2
jdbc:postgresql
jdbc:derby
jdbc:sqlserver
jdbc:sybase

What are these examples of?

Answer 5

Connection strings

Question 6

Whats the problem with hard-coding our DB details like this? What is the solution?

“static final String DATABASE_URL =
“jdbc:mysql://localhost:3306/books”;
Connection connection = null;
connection = DriverManager.getConnection(
DATABASE_URL, “CST8288”, “CST8288”)

Answer 6

It creates maintenance issues later. Solution is to use a properties class.

Note: “CST8288” is used as the username and password in the last Q

Question 7

Where is the JDBC driver located? What is the method you can use if it is not autoloaded?

Answer 7

mysql-connector-java.jar

Class.forName(“mysql-connector-java.jar”)

Question 8

T/F - DataSource and DataManager are the same

Answer 8

False. DataSource uses JNDI (Java Naming & Directory Interface) to look up the data source info

Question 9

DataSource requires a ____ serverq but we will not use DS in this course

Answer 9

JNDI

Question 10

Once we have a Connection instance we use ____________() to obtain an instance of statement.

Answer 10

createStatement

Question 11

Can createStatement be overloaded? How many arguments does the common form have?

Answer 11

Yes, 0 args

Question 12

How does PreparedStatement differ from Statement?

Answer 12

It’s a very similar (object), it just uses parameters

Question 13

Name this: Used to invoke a stored procedure in the DB

Answer 13

CallableStatement

Question 14

Once you have an instance of Statement you can call methods on it to perform SQL actions. ________() is used for SELECT and returns ResultSet, ___________() is used for INSERT, UPDATE< DELETE

Answer 14

ExecuteQuery()
ExecuteUpdate()

Question 15

Both ExecuteQuery() and ExecuteUpdate() are overloaded. In their simplest form they use a single _____ _______.

Answer 15

String argument.

Question 16

How do you get ResultSetMetaData?

Answer 16

Use getMetaData() with an instance of ResultSet

Question 17

With ResultSetMetaData, how did we obtain the count of columns, name of columns, and data type of columns?

Answer 17

Used getters on the instance of ResultSetMetaData

Question 18

When using ResultSetMetaData, how do the column numbers differ from arrays?

Answer 18

Column numbers start at 1.

Question 19

What method is used on a ResultSet instance to loop through each instance by row? Can hasNext() be used?

Answer 19

.next(). No.

Question 20

When you use .next() on a ResultSet instance for the first time, which is the first row that will be selected? Why?

Answer 20

Row #1. The “cursor” is placed before the first row.

Question 21

T/F - ResultSet can only retrieve rows going forward.

Answer 21

False, it can retrieve them in either direction.

Question 22

T/F - When ResultSet is changed it can change the underlying database immediately

Answer 22

True. This must be set using createStatement()

Question 23

Name this: Specifies that a ResultSet’s cursor can only move in the forward direction

Answer 23

TYPE_FORWARD_ONLY

Question 24

Name this: Specifies that ResultSet’s cursor can scroll in either direction and that the changes made to the underlying data during ResultSet processing are not reflected in the ResultSet unless the program queries the DB again.

Answer 24

TYPE_SCROLL_INSENSITIVE

Question 25

Specifies that a ResultSet’s cursor can scroll in either direction and that the changes made to teh underlying data during ResultSet processing are reflected immediately in the Result-Set

Answer 25

TYPE_SCROLL_SENSITIVE

Question 26

Specifies that a ResultSet can’t be updated–changes so the ResultSet contents cannot be reflected in the DB with ResultSet’s update methods

Answer 26

CONCUR_READ_ONLY

Question 27

Specifies that a ResultSet can be updated (i.e. changes so its contents can be reflected in the DB with ResultSet’s update methods)

Answer 27

CONCUR_UPDATABLE

Question 28

When closing our connections for the DB objects, which order is used?

Answer 28

ResultSet, Statement, Connection (Opposite of allocation order)

Question 29

What is the order that resources are allocated for DB objects?

Answer 29

Connection, Statement, ResultSet

Question 30

The Properties class is a subclass of ________, it stores a key along with a value (both are limited to type ______)

Answer 30

HashTable, String

Question 31

With the Properties class how can I get and set? How can I read from a file? How can I write to a file?

Answer 31

getProperty(), setProperty()

load()

list()

Question 32

What do we store in the Properties class?

Answer 32

JDBC connetion string, userid, pass