Q) How to implement batch updates in a JDBC applications?

->java.sql.statement and java.sql.prepared statement interfaces have methods to support batch processing.

1) addbatch (Strinf dml) :

This method used to add an SQL statement to the batch.

2) int [ ] executebatch() :
this method is used to submit the group of (batch of) SQL statements at a time to the DBMS.

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Q) Retrieving data from database?

A) ->to retrieve the data from database we need to submit SELECT statement from JDBC application. -> executeQuery() method of statement object is used for this purpose. This method has the fallowing ResultSet executeQuery(String sql) throws SQLException Ex: ResultSet rs = st.executeQuery(“SELECT * FROM ACCOUNT”); ->objectoriented representation of tables formate data is called ResultSet object. Ao the driver created one object i.e. ResultSet object. ->object orientation representation of a table of records returned from db is nothing but “ ResultSet ” object.

Q) Explain repeated deletion of records.

A) //RepeatedDeletion.java import java.util.Scanner; import java.sql.*; class RepeatedDeletion { public static void main(String[] args) { Connection con= DriverManager. getConnection ( "jdbc:odbc:prince" , "scott" , "tiger" ); PreparedStatement ps=con.PreparedStatement( "DELETE FROM ACCOUNT WHERE ACCNO=?" ); Scanner s= new Scanner(System. in ); while ( true ) { System. out .println( "Enter accno : " ); ...

Q) Develop a JDBC application that prompts the end-user to enter an employee number and displays the salary details.

A) //Retrieval.java import java.util.Scanner; import java.sql.DriverManager; import java.sql.Connection; import java.sql.Statement; import java.sql.ResultSet; class Retrieval { public static void main(String[] args) { Scanner s= new Scanner(System. in );System. out .println( "Enter employee number" ); int eno =s.nextInt(); Connection con=DriverManager. getConnection ( "jdbc:odbc:mydsn" , "scott" , "tiger"");" + Statement st=con.createStatement(); ...

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