character can be empty in mysql

Julian Morrison · **Posted:** Thu Nov 23, 2006 7:59 am

A bug in Hibernate core's org.hibernate.type.CharacterType, in public Object get(ResultSet rs, String name), there's a mistaken assumption that either the value is null or it always has a str.charAt(0).

In MySQL, a char(1) can contain an empty string.

This results in an error like

Code:

java.lang.StringIndexOutOfBoundsException: String index out of range: 0
        at java.lang.String.charAt(String.java:558)
        at org.hibernate.type.CharacterType.get(CharacterType.java:29)

This is still present in the latest version.

pasha · **Joined:** Sat Nov 27, 2004 4:13 am **Posts:** 137

mmm, I'm not sure, but it seems to be a MySQL problem instead of hibernate problem...

well when something is char(1) it must contain a single character...

even in MySQL an empty VARCHAR differs by null...

mephiztophelez · **Joined:** Wed Aug 10, 2005 12:36 pm **Posts:** 1

Hello,
we have the same problem here at a clients database.
MySQL Version: 5.0.27 Standard Community Edition

I have searched the forum. It seems that this is a problem for others too, but I couldnt find a solution so far.

Our case is the following:
We have an Order table, and there is a SQL CHAR(1) field.
But in some Orders there is an empty string "" in this column. The field is defined as

Code:

`myField` char(1) collate latin1_general_ci NOT NULL default 'N',

We use Hibernate with Annotations and the mapping of this field looks like:

Code:

@Column(name = "myField", unique = false, nullable = false, insertable = true, updatable = true, length = 1)
   public char getMyField() {
      return this.myField;
   }

Is there anything we can do from withhin Hibernate to prevent this? Either a change to the annotation.
I don;t know if we can manage to change anything at the database level.

Thanks
Christoph