Hibernate Mapping

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OnetoOne
UserDetails.java

@Entity
@Getter
@Setter
@Table(name="USER_DETAIL")
public class UserDetails 
{	
	@Id @GeneratedValue(strategy = GenerationType.AUTO)	
	private int UserId;	
	private String UserName;
	  
	@OneToOne
	private Vehicles veh;
}

Vehicles.java

@Entity
@Getter
@Setter
public class Vehicles 
{
	@Id @GeneratedValue
	private int vehicleId;
	
private String vehicleName;
}

CreateTable.java

public static void main(String[] args) 
  {
		UserDetails objUserDetail1 =  new UserDetails();
		objUserDetail1.setUserName("Mugil Vannan");
		
		Vehicles objVeh = new Vehicles();
		objVeh.setVehicleName("Suzuki");
		objUserDetail1.setVeh(objVeh);
		
		UserDetails objUserDetail2 =  new UserDetails();
		objUserDetail2.setUserName("Mani");
		
		Vehicles objVeh2 = new Vehicles();
		objVeh2.setVehicleName("Maruthi");
		objUserDetail2.setVeh(objVeh2);
		
		SessionFactory sessionFact = createSessionFactory();
		Session session = sessionFact.openSession();
		
		session.beginTransaction();				
		session.save(objUserDetail1);
		session.save(objVeh);
		session.save(objUserDetail2);
		session.save(objVeh2);
		session.getTransaction().commit();
		session.close();
  }

OnetoMany
UserDetails.java

@Getter
@Setter
@Entity
@Table(name="USER_DETAIL")
public class UserDetails 
{	
	@Id @GeneratedValue(strategy = GenerationType.AUTO)	
	private int UserId;	
	
        private String UserName;
	  
	@OneToMany	
        @JoinTable(joinColumns=@JoinColumn(name="USER_ID"),
	           inverseJoinColumns=@JoinColumn(name="VEHICLE_ID"))
	private List<Vehicles> arrVeh = new ArrayList<Vehicles>();
}

Vehicles.java

@Getter
@Setter
@Entity
public class Vehicles 
{
	@Id @GeneratedValue
	private int vehicleId;
	
        private String vehicleName;
}

CreateTables.java

 public static void main(String[] args) 
  {
        UserDetails objUserDetail1 =  new UserDetails();
        objUserDetail1.setUserName("Mugil Vannan");

        Vehicles objVeh = new Vehicles();
        objVeh.setVehicleName("Suzuki");
        objUserDetail1.getArrVeh().add(objVeh);

        Vehicles objVeh2 = new Vehicles();
        objVeh2.setVehicleName("Maruthi");
        objUserDetail1.getArrVeh().add(objVeh2);

        SessionFactory sessionFact = createSessionFactory();
        Session session = sessionFact.openSession();

        session.beginTransaction();				
        session.save(objUserDetail1);
        session.save(objVeh);
        session.save(objVeh2);
        session.getTransaction().commit();
        session.close();	
  }

ManytoOne
UserDetails.java

@Getter
@Setter
@Entity
@Table(name="USER_DETAIL")
public class UserDetails {	
	@Id @GeneratedValue(strategy = GenerationType.AUTO)	
	private int UserId;	
	
        private String UserName;
}

Vehicles.java

@Getter
@Setter
@Entity
public class Vehicles {
	@Id @GeneratedValue
	private int vehicleId;
	
        private String vehicleName;
	
	@ManyToOne	
	private UserDetails objUserDetails;
}

CreateTables.java

public static void main(String[] args) 
  {	
	Vehicles objVeh1 = new Vehicles();
        objVeh1.setVehicleName("Suzuki");

	Vehicles objVeh2 = new Vehicles();
	objVeh2.setVehicleName("Maruthi");

	UserDetails objUserDetail1 =  new UserDetails();
	objUserDetail1.setUserName("Mugil Vannan");
	
	objVeh1.setObjUserDetails(objUserDetail1);
	objVeh2.setObjUserDetails(objUserDetail1);
			
	SessionFactory sessionFact = createSessionFactory();
	Session session = sessionFact.openSession();

	session.beginTransaction();				
	session.save(objUserDetail1);		
	session.save(objVeh1);
	session.save(objVeh2);
	session.getTransaction().commit();
	session.close();	
  }

ManytoMany
UserDetails.java

@Getter
@Setter
@Entity
@Table(name="USER_DETAIL")
public class UserDetails {	
	@Id @GeneratedValue(strategy = GenerationType.AUTO)	
	private int UserId;	
	
        private String UserName;
	
	@ManyToMany
	private List<Vehicles> arrVehicles = new ArrayList<Vehicles>();
}

Vehicles.java

@Getter
@Setter
@Entity
public class Vehicles {
	@Id @GeneratedValue
	private int vehicleId;
	
        private String vehicleName;
	
	@ManyToMany(mappedBy="arrVehicles") 
	private List<UserDetails> arrUserDetails = new ArrayList<UserDetails>();
}

CreateTables.java

public static void main(String[] args) 
  {	
	Vehicles objVeh1 = new Vehicles();
	objVeh1.setVehicleName("Suzuki");
	
	Vehicles objVeh2 = new Vehicles();
	objVeh2.setVehicleName("Maruthi");
	
	UserDetails objUserDetail1 =  new UserDetails();
	objUserDetail1.setUserName("Mugil Vannan");
	
	UserDetails objUserDetail2 =  new UserDetails();
	objUserDetail2.setUserName("Mani");
	
	objVeh1.getArrUserDetails().add(objUserDetail1);
	objVeh1.getArrUserDetails().add(objUserDetail2);
	
	objUserDetail1.getArrVehicles().add(objVeh1);
	objUserDetail1.getArrVehicles().add(objVeh2);
							
	SessionFactory sessionFact = createSessionFactory();
	Session session = sessionFact.openSession();
	
	session.beginTransaction();				
	session.save(objUserDetail1);
	session.save(objUserDetail2);		
	session.save(objVeh1);
	session.save(objVeh2);
	session.getTransaction().commit();
	session.close();	
  }

Using Generator to generate Sequence

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@Entity
public class UserDetails 
{
@GenericGenerator(name="sequence-gen",strategy="sequence")
	@CollectionId(columns={@Column(name="Address_Id")}, generator="sequence-gen", type=@Type(type="long"))
private List<Address> arrList = new ArrayList<Address>();
.
.
.
}

Working with Collections in Hibernate

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While working with collection if you want the details to be stored in a seperate table using @ElementCollection solves the purpose

UserDetails.java

 public class UserDetails {
  @ElementCollection
  private List<Address> arrList = new ArrayList<Address>();

 }

Address.java

@Embeddable
public class Address 
{
  private String DoorNo;
  private String Street;
  private String Location;
  private String Pincode;
  .
  .
  .
 }

createTables.java

public class CreateTables {   
  public static void main(String[] args) 
  {
    UserDetails objUserDetail1 =  new UserDetails();

    Address objAddr = new Address();
    objAddr.setDoorNo("13");
    objAddr.setStreetName("Poes Road");
    objAddr.setLocation("Teynampet");
    objAddr.setPincode("600018");
    
    
    Address objAddr2 = new Address();
    objAddr2.setDoorNo("256");
    objAddr2.setStreetName("Sriman Srinivasan Road");
    objAddr2.setLocation("Alwarpet");
    objAddr2.setPincode("600018");
    
    objUserDetail1.getArrList().add(objAddr);
    objUserDetail1.getArrList().add(objAddr2);
  }
}

Giving Names to Joined Tables

  • New Table will be created under USER_ADDRESS Name
  • joinColumns decides which column should be used for joining two tables

Format for Join Table

  @JoinTable(name="JOIN_TABLE_DESIRED_NAME", 
	     joinColumns= @JoinColumn(name="userId"))

  @JoinTable(name="USER_ADDRESS", 
	     joinColumns= @JoinColumn(name="userId"))
  private Set<Address> addressSet = new HashSet();
  .
  .

Generating Unique Next ID in Process

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FOR cur IN (SELECT  process_Id 
              FROM  tbl_process)
LOOP
  SELECT (MAX(TO_NUMBER(substr(p.old_id, instr(p.old_id, '_', -1) + 1))))
    INTO new_id
    FROM tbl_process p
   WHERE process_Id = cur.process_Id;

  IF new_id IS NULL THEN
    new_id := cur.process_Id || '_1';
  ELSE
    new_id := new_id + 1;
    new_id := cur.process_Id || '_' || new_id;
  END IF;
END LOOP;

NULL or BLANK fields check in Oracle

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If you want a query which returns rows in column containing NULL or empty space then the using NULL alone in where clause will not return empty space rows. So the query should be altered as below

Actual Query

 SELECT COUNT (*) 
   FROM TABLE 
  WHERE COL_NAME IS NULL;

Altered Query

  SELECT COUNT (*) 
    FROM TABLE 
   WHERE trim(COL_NAME) IS NULL

(or)

Altered Query

  SELECT COUNT (*) 
    FROM TABLE  
    WHERE COL_NAME IS NULL OR 
          LENGTH(TRIM (COL_NAME)) = 0

Grouping and Sub Grouping Summing

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Rows as Displayed in Screen

Rows from Database

Rows grouping Logic

	List<RowsBean> outputList = RowsToBeDisplayedList;		
	
	HashMap<String, ArrayList>  superGroupPoints    = new HashMap<String, ArrayList>();	
	HashMap<String, EWMDecimal> subGroupTotalPoints = new HashMap<String, Integer>();	
	
	String groupName = null;
	String prevGroupName = null;
	String superGroupName = null;
	String prevSuperGroupName = null;	
	
	List<Map> subGroupPointsList = new ArrayList();	
	
	
	//Compute grouping totals
	Iterator itr = cicCarryPointsList.iterator();
	
	 while(itr.hasNext()) 
	 {
		RowsBean rowBean = (RowsBean) itr.next();		
		superGroupName   = rowBean.getSuperGroupName();
		groupName 		 = rowBean.getGroupName();
		
  	        //Addition of points summed at Group Level
		if ((prevGroupName != null && !prevGroupName.equals(groupName))
				|| (prevSuperGroupName != null &&    !prevSuperGroupName.equals(superGroupName)))
		{
		   subGroupPointsList.add(subGroupTotalPoints);
		   subGroupTotalPoints = new HashMap<String, Integer>();
		}
		
		
		//Rows at GroupLevel with Sub Groups should be added only when Super Group Changes 
		if((prevSuperGroupName != null && !prevSuperGroupName.equals(superGroupName)))
		{			   
		   superGroupPoints.put(prevSuperGroupName, (ArrayList) subGroupPointsList);
		   subGroupPointsList = new ArrayList();
		}
		
		Integer subGroupValPoints = rowBean.getPoints();		    

		//If InvGrp level Map exists 
		if (subGroupTotalPoints.get(groupName) != null) {
			Integer currSummedPointsAtGrpLevel = subGroupTotalPoints.get(groupName);
			currSummedPointsAtGrpLevel = currSummedPointsAtGrpLevel.add(subGroupValPoints);
			subGroupTotalPoints.put(groupName, currSummedPointsAtGrpLevel);				
		} else {
			subGroupTotalPoints.put(groupName, subGroupValPoints);
		}
		
		//Incase of last element the loop exits without adding last summed element
		//To prevent that we add it with out current and prev comparison
		if(!itr.hasNext())
		{
			subGroupPointsList.add(subGroupTotalPoints);				
			superGroupPoints.put(superGroupName, (ArrayList) subGroupPointsList);
		}
		
		prevSuperGroupName = superGroupName;
		prevGroupName = groupName;
	}

Retrieval of Rows for Displaying in Screen

String currentSuperGrouping = "";
String prevSuperGrouping    = "";
String currGrouping = "";
String prevGrouping = "";
String Value = "";
 
for (RowsBean rowBean : outputList)
{
	currentSuperGrouping = rowBean.getSuperGroupName();
	currGrouping = rowBean.getGroupName();

    //Level 1 - New Super Group Creation 
	//New Super Group should be created when ever prevSuperGrouping and  currentSuperGrouping are different
    if (!currentSuperGrouping.equals(prevSuperGrouping))
    {
      .
      .  
      Super Group Row Creation HTML Code Goes Here
      .
      .
      .
    }
     
    //Level 2 - Group addition under Super Group
	//New Group should be created when ever SuperGroup or Group Changes
    if(!currGrouping.equals(prevGrouping) || !currentSuperGrouping.equals(prevSuperGrouping))
    {
      //Taking Group Level Maps List
      ArrayList GroupLevelMapList = superGroup.get(rowBean.getGroupName());
      Iterator  itr =  GroupLevelMapList.iterator();
       
	  //Taking the Summed up value at Group Level from List
      while (itr.hasNext())
      {
         Map ii = (Map) itr.next();
         Points = ii.get(rowBean.getGroupName());      
      }  
       
      .
      .  
      Group Row Creation HTML Code Goes Here
      .
      .
      .
    }
     
    //Level 3 - Sub Group Rows Addition
	//Rows will be added 
    if(currentSuperGrouping.equals(rowBean.getGroupName) || currentSuperGrouping.equals(rowBean.getSubGroupName))
    {
      .
      .  
      Sub Group Row Creation HTML Code Goes Here
      .
      .
      .
    } 
     
    prevSuperGrouping    = currentSuperGrouping;
    prevGrouping = currGrouping;
}

Eclipse ANT Build Error

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      Right Click on build.xml
      Go to “Run As” >> “External Tools Configurations…”
      It shall open new window
      Go to JRE tab
      Select proper JRE if missing (sometimes jre tabs shows error mark on that.)

How to compare two columns in Excel

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formula to give you a comparison:

=AND(A2:A11=B2:B11)

Enter the formula by pressing Ctrl+Shift+Enter. If done correctly it will appear as the following:

{=AND(A2:A11=B2:B11)}

For a case-sensitive comparison, the equals operator will not work. Instead, the EXACT() function should be used. 

{=AND(EXACT(A2:A11,B2:B11))}