-
If i give two Class.forName how can i konw which driver is loading? whether it is possible or not?
vinaymudgil007
- Jun 8th, 2010
Yes it possible.... Please see public static Enumeration getDrivers() method in java.sql.DriverManager.DriverManager class which gives the complete list of Drivers available for use as an Enumeration.Thanks,Vinay
Supriya Ahire
- Feb 2nd, 2007
Hello, Yes , U can use two Class.forName() as Drivermanager keeps array internally to store the Drivernames so whichever come first will we loaded & used.Regards, Ms.Supriya Ahire
-
What are the Database transactions? How we can maintain transactions using JDBC? Explain with example?
vinaymudgil007
- Jun 8th, 2010
Database transactions => A group of SQL queries which should either all be executed or none should be executed will comprise of a tracnsaction.Maintain transactions using JDBC => We can do ...
trcdutt
- Feb 15th, 2008
Here is a skeleton of code for implementing a transaction.import java.sql.Connection;public class Test {public void AllTransactionStatements() { Connection con = getCon(); &nbs...
-
What is the difference between store procedures and prepared statement?
vinaymudgil007
- Jun 8th, 2010
To be straightforward, we can only compare two things when they are in the same scope/domain. This question says to differentiate b/w SPs and prepared statements isn't valid.Stored Procs are persi...
subhankar1982
- Feb 21st, 2009
Generally procedure and functions are written in PL/SQL code and it will reside in databases. When we develop some application in Java using JDBC to deal with specific databases for specific purpose...
-
A user leaves an online shopping cart without checking out.Which of the following interfaces will notify to rollback the transaction?
A user leaves an online shopping cart without checking out.Which of the following interfaces will notify to rollback the transaction?a)HttpSessionb)HttpSessionBindingListenerc)HttpServletd)SingleThreadModele)FtpSession
vinaymudgil007
- Jun 8th, 2010
(b)HttpSessionBindingListener is the correct answervalueBound() and valueUnbound() are the methods that should be over-ridden to get this implemented.Thanks.Vinay
phanikhk
- Apr 9th, 2008
Any class can implement HttpSessionBindingListener interface. This interface includes two methods, valueBound() and valueUnbound(), that are called whenever the object that implements the interfa...
-
State true or falseCan we retrieve a whole row of data at once, instead of calling an individual ResultSet.getXXX method for each column ?
A) TrueB) FalseExplanation: The ResultSet.getXXX methods are the only way to retrieve data from a ResultSet object, which means that you have to make a method call for each column of a row. It is unlikely that this is the cause of a performance problem, however, because it is difficult to see how a column could be fetched without at least the cost of a function call in any scenario.
vinaymudgil007
- Jun 8th, 2010
We can update the Row with the values of the result set via updateRow() but we can't fetch it and hence the answer is "NO" or falseThanks,Vinay
Praveen
- May 17th, 2006
we cannot retrieve a whole row of data at once.In JDBC getXXX() are the methods which are used to get the data from ResultSet by columnwise.
-
Which of the following statements is true regarding the failing of the class.forName in jdk 1.1.x.
A) A workaround is to explicitly call the method DriverManager.registerDriver(new YourDriverClass).B) The problem is due to race condition in the class loader.C) The race condition prevents the static section of code in the driver class from executing and registering the driver with the DriverManager.D) All the above.
-
What is the protocol is used in type4 driver?
vinaymudgil007
- Jun 8th, 2010
Per my understanding and knowledge over the years, its the Native [java specific] protocol that is used in type4 drivers !!!Thanks,Vinay
Spoorthi
- Sep 13th, 2006
jdbc:oracle:thin:@localhost:1521: our GlobalDatabasename
-
What is the use of BLOB, CLOB datatypes in JDBC
vinaymudgil007
- Jun 8th, 2010
These are used to store large amount of data into database like images, movie etc which are extremly large in size.Thanks,Vinay
madhuhari
- Apr 16th, 2007
BLOB(Binary Large Object) and CLOB(CharacterLargeObject) are SQL2 datatypes, which are introduced in JDBC 2.0 version. Suppose you have a requirement like, you want to store your content of resume(la...
-
ResultSet is an interface, How does it support rs.next()?
NAVEEN
- Jun 18th, 2007
Question: If Result Set is an interface, then why can we call methods like next(), isLast() etc. without defining the method body anywhere in the program? As I understand it, in an interface, methods...
-
What is the state of Connection object after execution of Statement(Populated Result Set)?
vinaymudgil007
- Jun 8th, 2010
The connection object is still open after the excecution unless explicitly closed by Connection.close() method.
venu
- Apr 10th, 2007
The connection object is still active, meaning it is ready to execute another statement.
-
What's going on
Is the driver get registred then where it is inintialized, if it is initialized & registerde there only, How?">In the Statement below class.forName(" ---");What's going onIs the driver get registred then where it is inintialized, if it is initialized & registerde there only, How?
vinaymudgil007
- Jun 8th, 2010
class.forName(" Any Class Name Here") is a static method in Class class which returns the Class object associated with the class or interface with the given string name.....So when I say cl...
subhankar1982
- Feb 21st, 2009
Every JDBC driver vendor providing a static block for Driver classprovided by vendor. Which taking care of creating driver class object and registaring driver class , so instead of writing code Ex:- D...
-
WasNull() method to handle null database fields
which of the following methods eliminates the need to call wasNull() method to handle null database fields?a)getObject()b)getInt()c)getString()d)getFloat()e)getNull()
vinaymudgil007
- Jun 8th, 2010
To my understanding, the question isn't framed properly. The answers given by two fellows above are ways to go around this situation but none eliminates the need to call wasNull().Other views are appreciated !!!
kittupeddi
- Apr 10th, 2008
Two Ways:1> Use the wasNull() method on the ResultSet.2> Use the getObject() method on the ResultSet and do the Comparision.
-
JDBC Isolation Level
Name the method that gives the existing isolation level in JDBC.
vinaymudgil007
- Jun 7th, 2010
Just to add more info to the above answer (public int getTransactionIsolation() throws SQLException from Connection interface) that their is always a trade-off between isolation level and concurrency ...
awasie
- Nov 14th, 2009
Isolation level represent how a database maintains data integrity against the problems like dirty reads, phantom reads and non-repeatable reads which can occur due to concurrent transactions. java.sql...
-
JDBC-ODBC Bridge
When would you use a JDBC-ODBC Bridge?
vinaymudgil007
- Jun 7th, 2010
We use JDBC-ODBC bridge only when pure JDBC drivers are not available [say for connecting to a database] otherwise pure Java drivers are a good optoion.The use of JDBC-ODBC drivers isn't recommended v...
hsavinash2001
- May 26th, 2010
It is not recommended to use because of the dependency on native language (This is implemented in C++)
-
SCROLLABLE_SENSITIVE resultset
Explain with examples for SCROLLABLE_SENSITIVE resultset?
mohanpatil
- May 15th, 2010
If resultset is sensitive then using stmt.refreshRow() method, you get the updated data which is recently changed by other client in the database.
pradeepkmr18
- Jun 27th, 2008
Scrollable means the cursor can move forward or backward and Sensitive meansex:If u are using SCROLLABLE_SENSITIVE resultset i.e u have opened the result setIf any other person makes changes like inse...
-
How do you implement Connection Pooling
tgnanakumar
- Apr 23rd, 2010
By using the J2EE servers like WebLogic, WebSphere, jBoss, Tomcat. We have to configure the data source object and connection pool object and supply the values as part of connection pool configu...
G.kirankumar
- Oct 6th, 2005
code for connecting the connection poolingInitalContext ic=new InitialContext();Hashtable ht=new Hashtable();ht.put("Context.INITIAL_PROVIDER",weblogic.jndi.InitialCla) //u have to set weblogic proper...
-
How can i connect oracle database from java program ? explain the steps with one example?
shalini shivhare
- Dec 26th, 2009
Step 1: Import JAVA Package:- import java.sql.*; Step 2: Register the driver with the following command:- Class.For.Name("sun.jdbc.odbc.JdbcOdbcDriver"); Step 3:- Create the connection with ...
RajNair
- Feb 9th, 2007
DriverManager.registerDriver(new Oracle:jdbc:OracleDriver());Connection con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE", "scott", "tiger");
-
Call stored procedure in Java using CallableStatements
How can we call a stored procedure in Java using CallableStatements? Give an example.
lilliput2009
- Nov 18th, 2009
import java.sql.CallableStatement;import java.sql.Connection;import java.sql.DriverManager;import java.sql.SQLException;public class Sample{ public static void main(String[] args) &...
pradeepkmr18
- Jul 3rd, 2008
first get connection objectConnection con=DriverManager.getConnection(); (we can get by datasourse object also)CallableStatement cstmt=con.prepareCall("{ call procedurename(?,?,?,?) }");cstmt.setString(1,ID);cstmt.setString(2,name);....ucount=cstmt.executeUpdate();
-
State true or false :- ResultSet.CONCUR_UPDATABLE used with the result set is used to update the rows directly in the database.
A) TrueB) FalseExplanation: This is the new feature in the JDBC 2.0 API usage is Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
anitpatel
- Nov 6th, 2009
True. One has to call insertRow() programmatically to get the resultset data changes reflected in database. The CONCUR_UPDATABLE implementation can be driver specific. If driver does not support this mode of update, it will not allow the resultset update.
-
Functionality of the cancel() method
What is the functionality of the cancel() method, provided in java.sql.Statement?
bino75
- Sep 16th, 2009
Cancels the Statement object if both the DBMS and driver support aborting an SQL statement. This method can be used by one thread to cancel a statement that is being executed by another thread.
JDBC Interview Questions
Ans