How to Use ParameterMetaData to Learn Parameter Information?

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In the following example, it shows various methods of the ParameterMetaData object are used to display information about the type and mode of the parameters that are contained within a stored procedure.

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ParameterMetaData;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Types;

public class JDBCPrepareMetaData {

    private static final String DBURL = 
            "jdbc:mysql://localhost:3306/mydb?user=usr&password=sql"
             +"&useUnicode=true&characterEncoding=UTF-8";
    private static final String DBDRIVER = "org.gjt.mm.mysql.Driver";
  
    static {
        try {
            Class.forName(DBDRIVER).newInstance();
        } catch (Exception e){
            e.printStackTrace();
        }
    }

    private static Connection getConnection() 
    {
        Connection connection = null;
        try {
            connection = DriverManager.getConnection(DBURL);
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        return connection;
    }

    public static void createEmployees()
    {
        Connection con = getConnection();
        Statement stmt =null;
        String createString;
        createString = "CREATE TABLE  `mydb`.`employees` ("+
          "`EmployeeID` int(10) unsigned NOT NULL default '0',"+
          "`Name` varchar(45) collate utf8_unicode_ci NOT NULL default '',"+
        "`Office` varchar(10) collate utf8_unicode_ci NOT NULL default '',"+
          "`CreateTime` timestamp NOT NULL default CURRENT_TIMESTAMP,"+
          "PRIMARY KEY  (`EmployeeID`)"+
          ") ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;";            
        try {
            stmt = con.createStatement();
            stmt.executeUpdate(createString);
        } catch(SQLException ex) {
            System.err.println("SQLException: " + ex.getMessage());
        }
        finally {
            if (stmt != null) {
                try {
                    stmt.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
        }
    }
    private static void dropEmployees()
    {
        Connection con = getConnection();
        Statement stmt =null;
        String createString;
        createString = "DROP TABLE IF EXISTS `mydb`.`employees`;";            
        try {
            stmt = con.createStatement();
            stmt.executeUpdate(createString);
        } catch(SQLException ex) {
            System.err.println("SQLException: " + ex.getMessage());
        }
        finally {
            if (stmt != null) {
                try {
                    stmt.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
        }
    }
    
    private static void insertEmployee() 
    {
        Connection con = getConnection();
        Statement stmt = null;

        try {
            stmt = con.createStatement();  

            stmt.addBatch("INSERT INTO employees(EmployeeID, Name, Office) "  
                   + "VALUES(1001, 'David Walker', 'HQ101')");

            stmt.addBatch("INSERT INTO employees(EmployeeID, Name, Office) "  
                    + "VALUES(1002, 'Paul Walker', 'HQ202')");            

            stmt.addBatch("INSERT INTO employees(EmployeeID, Name, Office) "  
                   + "VALUES(1003, 'Scott Warner', 'HQ201')");            

            int [] updateCounts = stmt.executeBatch();

        } catch (SQLException e) {
            System.err.println("SQLException: " + e.getMessage());
        }
        finally {
            if (stmt != null) {
                try {
                    stmt.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
        }
    }
    private    static void dropProcedure() {
        Connection con = getConnection();
        Statement stmt =null;
        try {
            stmt = con.createStatement();
            stmt.execute("DROP PROCEDURE IF EXISTS `mydb`.`WhoAreThey`");
        } catch(SQLException ex) {
            System.err.println("SQLException: " + ex.getMessage());
        }
        finally {
            if (stmt != null) {
                try {
                    stmt.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
        }
        
    }
    
    private    static void createProcedure() {
        Connection con = getConnection();
        Statement stmt =null;
        try {
            stmt = con.createStatement();
               stmt.execute("CREATE PROCEDURE `WhoAreThey`(" +
                       "OUT error VARCHAR(128)," +
                       "IN office VARCHAR(10)) " +
                       "BEGIN "+
                       "SET error = NULL; "+
                       "IF office IS NULL THEN "+
                       "SET error = 'You need to pass in an office number'; "+
                       "ELSE "+
                       "  SELECT EmployeeID, Name FROM employees " + 
                       " WHERE office = office; "+
                       "END IF; "+
                       "END");

        } catch(SQLException ex) {
            System.err.println("SQLException: " + ex.getMessage());
        }
        finally {
            if (stmt != null) {
                try {
                    stmt.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
        }
        
    }

    public static void getParameterMetaData() {
        Connection con = getConnection();
        PreparedStatement stmt = null;

        try {
            stmt = con.prepareStatement("INSERT INTO " +
                  employees(EmployeeID, Name, Office) " + 
                    "VALUES(?,?,?)");  

            ParameterMetaData pmd = stmt.getParameterMetaData();
            int count = pmd.getParameterCount();
            for (int i = 1; i <= count; i++) {
                System.out.println("Name: " + pmd.getParameterType(i));
                System.out.println("TYPE: " + pmd.getParameterTypeName(i));
                String mode = "";
                switch(pmd.getParameterMode(i)) {
                     case ParameterMetaData.parameterModeIn:
                         mode = "IN";
                         break;
                     case ParameterMetaData.parameterModeInOut:
                         mode = "IN/OUT";
                         break;
                     case ParameterMetaData.parameterModeOut:
                         mode = "OUT";
                         break;
                     case ParameterMetaData.parameterModeUnknown:
                         mode = "UNKNOWN";
                         break;
                
                }
                System.out.println("MODE: " + mode);
            }

        } catch (SQLException e) {
            System.err.println("SQLException: " + e.getMessage());
        }
        finally {
            if (stmt != null) {
                try {
                    stmt.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
        }
        
    }

    public static void getProcedureParameterMetaData() {
        Connection con = getConnection();
        CallableStatement cs = null;
        try {
            cs = con.prepareCall("{call WhoAreThey(?,?)}");
            ParameterMetaData pmd = cs.getParameterMetaData();
            int count = pmd.getParameterCount();
            for (int i = 1; i <= count; i++) {
                System.out.println("Name: " + pmd.getParameterType(i));
                System.out.println("TYPE: " + pmd.getParameterTypeName(i));
                String mode = "";
                switch(pmd.getParameterMode(i)) {
                     case ParameterMetaData.parameterModeIn:
                         mode = "IN";
                         break;
                     case ParameterMetaData.parameterModeInOut:
                         mode = "IN/OUT";
                         break;
                     case ParameterMetaData.parameterModeOut:
                         mode = "OUT";
                         break;
                     case ParameterMetaData.parameterModeUnknown:
                         mode = "UNKNOWN";
                         break;
                
                }
                System.out.println("MODE: " + mode);
            }
            
        } catch (SQLException e) {
            System.err.println("SQLException: " + e.getMessage());
        }
        finally {
            if (cs != null) {
                try {
                    cs.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    System.err.println("SQLException: " + e.getMessage());
                }
            }
        }
        
    }

    public static void main(String[] args) {
        dropProcedure();
        dropEmployees();
        createEmployees();
        insertEmployee();
        getParameterMetaData();
        System.out.println("Call Procedure.....");
        createProcedure();
        getProcedureParameterMetaData();
    }

}

WebSphere MQ Interview Questions

What is MQ and what does it do? Ans. MQ stands for MESSAGE QUEUEING. WebSphere MQ allows application programs to use message queuing to participate in message-driven processing. Application programs can communicate across different platforms by using the appropriate message queuing software products. What is Message driven process? Ans . When messages arrive on a queue, they can automatically start an application using triggering . If necessary, the applications can be stopped when the message (or messages) have been processed. What are advantages of the MQ? Ans. 1. Integration. 2. Asynchrony 3. Assured Delivery 4. Scalability. How does it support the Integration? Ans . Because the MQ is independent of the Operating System you use i.e. it may be Windows, Solaris,AIX.It is independent of the protocol (i.e. TCP/IP, LU6.2, SNA, NetBIOS, UDP).It is not required that both the sender and receiver should be running on the same platform What is Asynchrony? Ans. With message queuing, the ex...

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