Marina-
The problem is that OpenJPA just ignores extra, unmapped columns.
Since we don't require that you map all of the columns of a database
table to an entity, tables can exist that have unmapped columns. By
default, we tend to err on the side of caution, so we never drop
tables or columns. The "deleteTableContents" flag merely deletes all
the rows in a table, it doesn't actually drop the table.
We don't have any options for asserting that the table is mapped
completely. That might be a nice enhancement, and would allows
OpenJPA to warn when it sees a existing table with unmapped columns.
You could manually drop the tables using the mappingtool by
specifying the "schemaAction" argument to "drop", but there's no way
to do it automatically using the SynchronizeMappings. Note that there
is nothing preventing you from manually invoking the MappingTool
class from any startup to glue code that you want.
On Mar 29, 2007, at 4:18 PM, Marina Vatkina wrote:
Marc, Patrick,
I didn't look into the file story yet, but what I've seen as the
result of using
<property name="openjpa.jdbc.SynchronizeMappings"
value="buildSchema
(SchemaAction='add,deleteTableContents')"/>
looks surprising: if I have there is an entity Foo with persistence
fields 'x' and 'y' and a table FOO already exists in the database
with columns A and B (there are no fields 'a' and 'b' in the
entity), the table is not recreated, but the columns X and Y are
added to the table FOO. The 'deleteTableContents' doesn't affect
this behavior.
Is it an expected behavior?
What should I use to either create the table properly or get a
message that such table already exist (and as in my case doesn't
match the entity)?
thanks,
-marina
Marina Vatkina wrote:
Then I'll first start with an easier task - check what happens in
EE if entities are not explicitly listed in the persistence.xml
file :).
thanks,
-marina
Marc Prud'hommeaux wrote:
Marina-
Let me give it a try. How would the persistence.xml property
look like to generate .sql file?
Actually, I just took a look at this, and it look like it isn't
possible to use the "SynchronizeMappings" property to
automatically output a sql file. The reason is that the property
takes a standard OpenJPA plugin string that configures an
instances of MappingTool, but the MappingTool class doesn't have
a setter for the SQL file to write out to.
So I think your only recourse would be to write your own adapter
to to this that manually creates a MappingTool instance and runs
it with the correct flags for outputting a sql file. Take a look
at the javadocs for the MappingTool to get started, and let us
know if you have any questions about proceeding.
On Mar 20, 2007, at 4:59 PM, Marina Vatkina wrote:
Marc,
Marc Prud'hommeaux wrote:
Marina-
They do in SE, but as there is no requirement to do it in
EE, people try to reduce the amount of typing ;).
Hmm ... we might not actually require it in EE, since we do
examine the ejb jar to look for persistent classes. I'm not
sure though.
You should test with both listing them and not listing them.
I'd be interested to know if it works without.
Let me give it a try. How would the persistence.xml property
look like to generate .sql file? Where will it be placed in EE
environment? Does it use use the name as-is or prepend it with
some path?
thanks.
On Mar 20, 2007, at 4:19 PM, Marina Vatkina wrote:
Marc,
Marc Prud'hommeaux wrote:
Marina-
On Mar 20, 2007, at 4:02 PM, Marina Vatkina wrote:
Marc,
Thanks for the pointers. Can you please answer the
following set of questions?
1. The doc requires that "In order to enable automatic
runtime mapping, you must first list all your persistent
classes". Is this true for EE case also?
Yes. People usually list them all in the <class> tags in
the persistence.xml file.
They do in SE, but as there is no requirement to do it in
EE, people try to reduce the amount of typing ;).
If OpenJPA can identify all entities in EE world, why can't
it do the same for the schema generation?
I'll check the rest.
thanks,
-marina
2. Section "1.2.Generating DDL SQL" talks about .sql files,
but what I am looking for are "jdbc" files, i.e. files
with the lines that can be used directly as java.sql
statements to be executed against database.
The output should be sufficient. Try it out and see if the
format is something you can use.
3. Is there a document that describes all possible values
for the "openjpa.jdbc.SynchronizeMappings" property?
Unfortunately, no. Basically, the setting of the
"SynchronizeMappings" property will be of the form "action
(Bean1=value1,Bean2=value2)", where the "bean" values are
those listed in org.apache.openjpa.jdbc.meta.MappingTool
(whose javadoc you can see http://incubator.apache.org/
openjpa/ docs/latest/ javadoc/org/ apache/openjpa/jdbc/meta/
MappingTool.html ).
thank you,
-marina
Marc Prud'hommeaux wrote:
Marina-
On Mar 15, 2007, at 5:01 PM, Marina Vatkina wrote:
Hi,
I am part of the GlassFish persistence team and was
wondering how does OpenJPA support JPA auto DDL
generation (we call it "java2db") in a Java EE
application server.
Our application server supports java2db via creating two
sets of files for each PU: a ...dropDDL.jdbc and
a ...createDDL.jdbc file on deploy (i.e. before the
application is actually loaded into the container) and
then executing 'create' file as the last step in
deployment, and 'drop' file on undeploy or the 1st step
in redeploy. This allows us to drop tables created by
the previous deploy operation.
This approach is done for both, the CMP and the default
JPA provider. It would be nice to add java2db support
for OpenJPA as well, and I'm wondering if we need to
do anything special, or it'll all work just by itself?
We do have support for runtime creation of the schema via
the "openjpa.jdbc.SynchronizeMappings" property. It is
described at:
http://incubator.apache.org/openjpa/docs/latest/
manual/ manual.html#ref_guide_mapping_synch
The property can be configured to run the mappingtool
(also described in the documentation) at runtime
against all the registered persistent classes.
Here are my 1st set of questions:
1. Which API would trigger the process, assuming the
correct values are specified in the persistence.xml
file? Is it:
a) <provider>.createContainerEntityManagerFactory(...)? or
b) the 1st call to emf.createEntityManager() in this VM?
c) something else?
b
2. How would a user drop the tables in such environment?
I don't think it can be used to automatically drop then
create tables. The "mappingtool" can be executed
manually twice, the first time to drop all the tables,
and the second time to re- create them, but I don't
think it can be automatically done at runtime with the
"SynchronizeMappings" property.
3. If the answer to either 1a or 1b is yes, how does the
code distinguish between the server startup time and
the application being loaded for the 1st time?
That is one of the reasons why we think it would be
inadvisable to automatically drop tables at runtime :)
4. Is there a mode that allows creating a file with the
jdbc statements to create or drop the tables and
constraints?
Yes. See:
http://incubator.apache.org/openjpa/docs/latest/
manual/ manual.html#ref_guide_ddl_examples
thank you,
-marina
