Marina-
The "sql" flag merely says that OpenJPA should write the SQL to an
external file. It still needs to connect to the database in order to
see which tables currently exist, so it can determine if it needs to
create new tables or columns.
If you just want a "fresh" database view for the mapping tool, such
that the mapping tool thinks that the database has no schema defined,
then you can specify the "-SchemaFactory" flag to be "file(my-
schema.xml)", where my-schema.xml file is a schema definition file
(see docs to the format) that contains no tables or columns. This
should also prevent OpenJPA from having to connect to the database in
order to read the columns and tables.
On Mar 30, 2007, at 4:58 PM, Marina Vatkina wrote:
Marc,
I'm trying to run MappingTool to look at -sql option, but I can't
make it to work with a PU without connecting to the database (my
persistence.xml has <jta-data-source>), and I can't find in the
docs how to specify the DBDictionary without persistence.xml.
thanks,
-marina
Marc Prud'hommeaux wrote:
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
