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Mapping enum to database column using JPA/Hibernate You can use any of the 3 approaches discussed above. Map the enum to an integer column. The persistence implementation should automatically convert enum to ordinal() and back for you. Map the enum to a String column. The persistence implementation should automatically convert the enum value to String value via the name() function. Map the enum using a business value. You should mark the enum field as @Transient, and create another String field which you can map to a String column in your database table. Here’s an example code snippet. view plaincopy to clipboardprint?@Entity  public class Product {   @Column   private String colorValue;     @Transient   public Color getColor() {    return Color.fromValue(colorValue);   }     public void setColor(Color color) {    this.colorValue = color.toValue();   }  }  

Approach 3: Using a user defined business value – Recommended approach! This approach involves assigning a an explicit user defined value to each enum constant and defining a toValue() and fromValue() methods on the enum to do the serialization and deserialization.

public enum Color {   RED("RED"), GREEN("GREEN"), BLUE("BLUE"), UNKNOWN("UNKNOWN");     private final String value;     Color(String value) {     this.value = value;   }     public static Color fromValue(String value) {     if (value != null) {       for (Color color : values()) {         if (color.value.equals(value)) {           return color;         }       }     }       // you may return a default value     return getDefault();     // or throw an exception     // throw new IllegalArgumentException("Invalid color: " + value);   }     public String toValue() {     return value;   }     public static Color getDefault() {     return UNKNOWN;   }  }  public enum Color { RED("RED"), GREEN("GREEN"), BLUE("BLUE"), UNKNOWN("UNKNOWN"); private final String value; Color(String value) { this.value = value; } public static Color fromValue(String value) { if (value != null) { for (Color color : values()) { if (color.value.equals(value)) { return color; } } } // you may return a default value return getDefault(); // or throw an exception // throw new IllegalArgumentException("Invalid color: " + value); } public String toValue() { return value; } public static Color getDefault() { return UNKNOWN; } } This approach is better than approach 1 and approach 2 above. It neither depends on the order in which the enum constants are declared nor on the constant names.

Known Limitations

Gas3 does not support inner classes

Inheritance

hardest part of persisting inheritance is choosing how to represent the inheritance in the database

There are three inheritance strategies defined from the InheritanceType enum,

Java 5 EnumUserType

Cascading

following operations can be cascaded, as defined in the CascadeType enum:

stupid data container

used to transport data between layers and tiers