枚举Java类型的正确DB字段数据类型是什么

Question

I have this enum created:

    public enum CicloEnum {
        CL("Ciclo Largo"),
        CC("Ciclo Corto"),
        CI("Ciclo Intermedio");

        private String descripcion;

        private CicloEnum(String descripcion) {
            this.setDescripcion(descripcion);
        }

        public String getDescripcion() {
            return descripcion;
        }

        public void setDescripcion(String descripcion) {
            this.descripcion = descripcion;
        }
       }

and I want to persist the value in the DB, I'm using hibernate as ORM engine.

    @Entity
    @Table(name="bloquecruzamiento")
    public class BloqueCruzamiento {
         //...
         private CicloEnum ciclo;
         //...
        /**
         * @return the ciclo
         */
            public CicloEnum getCiclo() {
            return ciclo;
        }

        /**
         * @param ciclo the ciclo to set
         */
        public void setCiclo(CicloEnum ciclo) {
            this.ciclo = ciclo;
        }

The question is, that I want the field in the Database to be numeric, but is no big deal if it is creates as Varchar. How can I achieve the goal that the field in the database were created as int(2)? what do I need to add to the Enum definition?

Best Regards

Answer 1

Since by default, the values of ENUMS in Java are ordinal, you can set them with an array like manner. The only change would be to convert this enum back to an integer value. The change I made to your enum class was to add a function to do so:

public enum CicloEnum {
    CL("Ciclo Largo"), CC("Ciclo Corto"), CI("Ciclo Intermedio");

    private String descripcion;

    private CicloEnum(String descripcion) {
        this.setDescripcion(descripcion);
    }

    public String getDescripcion() {
        return descripcion;
    }

    public void setDescripcion(String descripcion) {
        this.descripcion = descripcion;
    }


    public int toIntForDatabase() {
        switch (this) {
        case CL:
            return 0;
        case CC:
            return 1;
        case CI:
            return 2;
        }
        return -1;
    }
}

Then, you can set the enum by calling MyEnum.values()[x] where MyEnum is the name of your enum, and x is the value of the integer that it would represent. For example, CL is 0, CC is 1, CI is 2. An example test that I wrote is:

public static void main(String[] args) throws Exception {

    int i = 1;
    CicloEnum ce = CicloEnum.values()[i];
    System.out.println(ce.getDescripcion());
    System.out.println(ce.toIntForDatabase());

}

This sets an enum based on an integer "i" (the value from your database), and then converts it back to an integer for the database using the toIntForDatabase() function.