Hibernate database specific columnDefinition values

Question

the problem is as follows: We're using hibernate with annotations as O/R Mapper.

Some @Column annotations look like:

@Column(columnDefinition = "longblob", name = "binaryData", nullable = true)

or

@Column(columnDefinition = "mediumtext", name = "remark", nullable = true)

with the columnDefinition attributes being mysql specific

on postgres for example, the columnDefinition values should be "bytea" and "varchar(999999)"

and on oracle probably something else.

Problems arise currently at the time of Schema Export, e.g. when creating the DDL statements.

Possible workarounds that I can think of are - Hack some JDBC driver that does a text replace (e.g. longblob->bytea) for the DDL statements. That's ugly but will work somehow - Use hibernate xml configuration instead of annotations. That will probably work but I prefer annotations

Does anybody know any alternatives? Hibernate specific workarounds are ok, e.g. if the columnDefinition attribute can contain dialect specific values like

@Column(columnDefinition = "mysql->mediumtext, postgres->varchar(999999)", name = "remark", nullable = true)

Thanks Holger

Do you know that, if you find an answer useful, you can vote for it. Click on the UP arrow on the left of the answer. :-) — KLE
– KLE, Commented Dec 24, 2009 at 14:07
This provides a solution specific for UUIDs, it's not pretty: stackoverflow.com/a/48918942/2102158 — Jon N
– Jon N, Commented Feb 22, 2018 at 3:01

Bozho · Accepted Answer · 2009-12-22 08:20:49Z

12

Why don't you use the database-agnostic annotations like:

@Lob (on a byte[] or a String property)
@Column(length=90000) (on a String property)

and see what columns will be generated in the database. They will most likely be of the types you want them to be.

answered Dec 22, 2009 at 8:20

Bozho

599k147 gold badges1.1k silver badges1.2k bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

user1946784 Over a year ago

Hello, thanks I wasn't aware of that, that seems to work. Best regards Holger

Tarion Over a year ago

And how to fix this for columnDefinition="json" where I can't decide if it's json based on the type. Postgres understands the json fine, but in H2 the column creation will just fail. I want hibernate to map the column name to string in that case.

Rhubarb Over a year ago

did you ever solve this @Tarion?

Tarion Over a year ago

I don't think so. It's long time ago.

KLE · Accepted Answer · 2009-12-22 07:39:56Z

4

Some ideas:

Use annotation in general, but overload them from Xml in the case where they are specific to your database. Then you can have one configuration file specific to your database.
Use java Constants in your annotations (they have to be compile-time constants, so you are limited). You can have several sets of Java constants, and point toward the one you want to export to. (Beware, when you point toward another constant, you have to recompile everything.)
I have also used the dialect to switch some code in my Configuration class. The configuration class receives all data (from annotations or xml), and can then postprocess it.

For example, I have changed the concatenation symbol from '||' on Oracle to '+' on SqlServer.
This is conveniently done at runtime :-)

edited Dec 22, 2009 at 7:39

answered Dec 22, 2009 at 7:24

KLE

24.2k4 gold badges58 silver badges62 bronze badges

2 Comments

user1946784 Over a year ago

Thanks - I already have the columnDefinition properties as constants for easier searching. Didn't know that annotations can be overloaded though - thanks!

user1946784 Over a year ago

Thanks, I'm currently finishing the migration to @Lob / @Column(length=90000) annotations which I prefer over modifying the hibernate Dialect. However, that would probably be my second option if the first one failed.

Collectives™ on Stack Overflow

Hibernate database specific columnDefinition values

2 Answers 2

4 Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related