DDevelopment & Design

Hibernate hbm2ddl won’t create schema before creating tables

Situation I have a local H2 in memory database for integration tests and an Oracle db for production. I do not control the Oracle DB model. The in memory H2 database is created automatically by adding <prop key=”hibernate.hbm2ddl.auto”>update&l…Situation I have a local H2 in memory database for integration tests and an Oracle db for production. I do not control the Oracle DB model. The in memory H2 database is created automatically by adding <prop key=”hibernate.hbm2ddl.auto”>update&l…

Situation I have a local H2 in memory database for integration tests and an Oracle db for production. I do not control the Oracle DB model. The in memory H2 database is created automatically by adding

update

  to hibernate properties in AnnotationSessionFactoryBean. The definition of the entity stored in DB points to a schema

@Entity
@Table(name = "business_operations", schema = "sowa")
public class BusinessOperation {
...

The problem When creating the H2 database, Hibernate won’t create the schema before creating tables. As a result it will show errors when trying to create the tables in non existing schema and fail in any query (queries will be run with sowa.business_operations).

2011-01-18 15:13:30,884 INFO [org.hibernate.tool.hbm2ddl.SchemaUpdate] - Running hbm2ddl schema update
2011-01-18 15:13:30,885 INFO [org.hibernate.tool.hbm2ddl.SchemaUpdate] - fetching database metadata
2011-01-18 15:13:30,915 INFO [org.hibernate.tool.hbm2ddl.SchemaUpdate] - updating schema
2011-01-18 15:13:30,927 INFO [org.hibernate.tool.hbm2ddl.DatabaseMetadata] - table not found: business_operations
2011-01-18 15:13:30,941 ERROR [org.hibernate.tool.hbm2ddl.SchemaUpdate] - Unsuccessful: create table sowa.business_operations 
2011-01-18 15:13:30,942 ERROR [org.hibernate.tool.hbm2ddl.SchemaUpdate] - 
Schema "SOWA" not found;

Turns out this bug is reported and open since 2006:

link. The solution The solution to this problem is to create the schema before hibernate’s hbm2ddl turns on. That would be easy with H2 if we could tell H2 to initialize itself like this:

database.url=jdbc:h2:mem:;INIT=RUNSCRIPT FROM 'src/main/resources/scripts/create.sql';

All seems nice, except H2 RUNSCRIPT FROM command doesn’t work with relative resources as you may expect. Fortunatelly INIT allows us to give any commands, not just point to a script, so this little change will solve the problem:

database.url=jdbc:h2:mem:;INIT=create schema IF NOT EXISTS sowa

Yeah, I know it’s obvious and simple stupid, but looking at all the questions on all the mailing lists in google I may have just saved a little bit of somebody’s time.

Solution Architect @ TouK

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Phonegap / Cordova and cross domain ssl request problem on android.

In one app I have participated, there was a use case:
  • User fill up a form.
  • User submit the form.
  • System send data via https to server and show a response.
During development there wasn’t any problem, but when we were going to release production version then some unsuspected situation occurred. I prepare the production version accordingly with standard flow for Android environment:
  • ant release
  • align
  • signing
During conduct tests on that version, every time I try to submit the form, a connection error appear. In that situation, at the first you should check whitelist in cordova settings. Every URL you want to connect to, must be explicit type in: 
res/xml/cordova.xml
If whitelist looks fine, the error is most likely caused by inner implementation of Android System. The Android WebView does not allow by default self-signed SSL certs. When app is debug-signed the SSL error is ignored, but if app is release-signed connection to untrusted services is blocked.



Workaround


You have to remember that secure connection to service with self-signed certificate is risky and unrecommended. But if you know what you are doing there is some workaround of the security problem. Behavior of method 
CordovaWebViewClient.onReceivedSslError
must be changed.


Thus add new class extended CordovaWebViewClient and override ‘onReceivedSslError’. I strongly suggest to implement custom onReceiveSslError as secure as possible. I know that the problem occours when app try connect to example.domain.com and in spite of self signed certificate the domain is trusted, so only for that case the SslError is ignored. 

public class MyWebViewClient extends CordovaWebViewClient {

   private static final String TAG = MyWebViewClient.class.getName();
   private static final String AVAILABLE_SLL_CN 
                               = "example.domain.com";

   public MyWebViewClient(DroidGap ctx) {
       super(ctx);
   }

   @Override
   public void onReceivedSslError(WebView view, 
                                  SslErrorHandler handler, 
                                  android.net.http.SslError error) {

       String errorSourceCName = error.getCertificate().
                                  getIssuedTo().getCName();

       if( AVAILABLE_SLL_CN.equals(errorSourceCName) ) {
           Log.i(TAG, "Detect ssl connection error: " + 
                       error.toString() + 
                       „ so the error is ignored”);

           handler.proceed();
           return;
       }

       super.onReceivedSslError(view, handler, error);
   }
}
Next step is forcing yours app to  use custom implementation of WebViewClient. 

public class Start extends DroidGap
{
   private static final String TAG = Start.class.getName();

   @Override
   public void onCreate(Bundle savedInstanceState)
   {
       super.onCreate(savedInstanceState);
       super.setIntegerProperty("splashscreen", R.drawable.splash);
       super.init();

       MyWebViewClient myWebViewClient = new MyWebViewClient(this);
       myWebViewClient.setWebView(this.appView);

       this.appView.setWebViewClient(myWebViewClient);
       
       // yours code

   }
}
That is all ypu have to do if minSdk of yours app is greater or equals 8. In older version of Android there is no class 
android.net.http.SslError
So in class MyCordovaWebViewClient class there are errors because compliator doesn’t see SslError class. Fortunately Android is(was) open source, so it is easy to find source of the class. There is no inpediments to ‘upgrade’ app and just add the file to project. I suggest to keep original packages. Thus after all operations the source tree looks like:

Class SslError placed in source tree. 
 Now the app created in release mode can connect via https to services with self-signed SSl certificates.