CODEWITHSUNDEEP
mysqldatabasehibernate
user10738240
user10738240

Reputation:

How to have UNIQUE field empty?

I've bar-code filed in a database table that is UNIQUE.
But field is not mandatory so I want to keep it empty.
I tried put null but it is bad idea to do.
Cause I'm using Hibernate so hibernate.hbm.xml doesn't generate wrapper class Integer that could be : 

<property name="barcode" type="java.lang.Integer">
        <column name="barcode" />

So above expression allow null insertion.
Instead it generate UNIQUE field as follow :

<property name="barcode" type="java.lang.Integer">
    <column name="barcode" unique="true" />

But I have make barcode in database table UNIQUE and nullable.
That don't help anyway.

So how can I keep it empty or other way around to deal with it.

Upvotes: 1

Views: 33

Answers (1)

CodyTheCoder
CodyTheCoder

Reputation: 74

null indicates the lack of data. It is perfectly reasonable to use null in a UNIQUE column as long as long as the column is not also set as NOT NULL.

Upvotes: 1

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