• Post Reply
  • Bookmark Topic Watch Topic
  • New Topic

How to not reinialize tables created with JPA?

 
Siegfried Heintze
Ranch Hand
Posts: 403
  • 0
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
This example seems to work: http://javahowto.blogspot.com/2006/07/helloworld-with-jpa-toplink-and-mysql.html

However, when I comment out the statements that create and delete the objects (as I have done below), I expect to see it display the same greetings and messages. Instead, no messages are being retrieved. Apparently something is recreating the database tables every time I run the program. What do change so I can run this program and see the data previously entered into the database?

Thanks,
Siegfried

HelloWorld.java:


Greeting.java:


Message.java:
 
Vesa Tanhua-Tyrkk´┐Ż
Greenhorn
Posts: 25
  • 0
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi,

This is configured in persistence.xml by property:
<property name="toplink.ddl-generation" value="drop-and-create-tables"/>

possible values for this are create-tables, drop-and-create-tables,none

So I think that by removing that property form persistence.xml preserves your data.
 
It is sorta covered in the JavaRanch Style Guide.
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic