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Java Persist without Entity

I am working on an JavaEE application, and there are almost 1000+ tables in the database, now I have to query the records by the parametes from the client.
Generally I will create one Entity for each table, and create the Dao,Service to do the query.
However I meet two problems:
1 Number of the tables
As I said, 1000+ table with almost 40+ columns for each, it would a nightmare to create the entity one by one.
2 Scheme update
Even I can create the Entity by program, the schema of the data may change sometime which is out of my control.
And in my application, only read operations are related to these kinds of data,no update,delete,create required.
So I wonder if the following solution is possible:
1 Use Map instead of POJOs
Do not create POJOs at all, use the native Map to wrap the columns and values.
2 Row mapping
When querying using Hibernate or Spring JdbcTemplate or something else, use a mapper to map each row to an entry in the map.
If yes, I would use the ResultMetaData to detect the column name,type,value:
ResultMetaData rmd=rs.getMetaData();
for(int i=0;i<rmd.getColumnCount();i++){
Type t=rmd.getType(i)
if(t==....){
...
}else if(t=...){
...
}
}
Looks like part of JPA's job, any library can used here?
If not, any other alternatives?

Join Postgresql rows with Mongodb documents based on specific columns

I'm using MongoDB and PostgreSQL in my application. The need of using MongoDB is we might have any number of new fields that would get inserted for which we'll store data in MongoDB.
We are storing our fixed field values in PostgreSQL and custom field values in MongoDB.
E.g.
**Employee Table (RDBMS):**
id Name Salary
1 Krish 40000
**Employee Collection (MongoDB):**
{
<some autogenerated id of mongodb>
instanceId: 1 (The id of SQL: MANUALLY ASSIGNED),
employeeCode: A001
}
We get the records from SQL, and from their ids, we fetch related records from MongoDB. Then map the result to get the values of new fields and send on UI.
Now I'm searching for some optimized solution to get the MongoDB results in PostgreSQL POJO / Model so I don't have to fetch the data manually from MongoDB by passing ids of SQL and then mapping them again.
Is there any way through which I can connect MongoDB with PostgreSQL through columns (Here Id of RDBMS and instanceId of MongoDB) so that with one fetch, I can get related Mongo result too. Any kind of return type is acceptable but I need all of them at one call.
I'm using Hibernate and Spring in my application.

Using Spring Data might be the best solution for your use case, since it supports both:
JPA
MongoDB
You can still get all data in one request but that doesn't mean you have to use a single DB call. You can have one service call which spans to twp database calls. Because the PostgreSQL row is probably the primary entity, I advise you to share the PostgreSQL primary key with MongoDB too.
There's no need to have separate IDs. This way you can simply fetch the SQL and the Mongo document by the same ID. Sharing the same ID can give you the advantage of processing those requests concurrently and merging the result prior to returning from the service call. So the service method duration will not take the sum of the two Repositories calls, being the max of these to calls.

Astonishingly, yes, you potentially can. There's a foreign data wrapper named mongo_fdw that allows PostgreSQL to query MongoDB. I haven't used it and have no opinion as to its performance, utility or quality.
I would be very surprised if you could effectively use this via Hibernate, unless you can convince Hibernate that the FDW mapped "tables" are just views. You might have more luck with EclipseLink and their "NoSQL" support if you want to do it at the Java level.
Separately, this sounds like a monstrosity of a design. There are many sane ways to do what you want within a decent RDBMS, without going for a hybrid database platform. There's a time and a place for hybrid, but I really doubt your situation justifies the complexity.
Just use PostgreSQL's json / jsonb support to support dynamic mappings. Or use traditional options like storing json as text fields, storing XML, or even EAV mapping. Don't build a rube goldberg machine.

JPA Multilingual sorting

Recently I am working on a bilingual project and for some reference tables I need to sort the data. But because it is bilingual, the data is coming from different languages (in my case English and French) and I like to sort them all together, for example, Île comes before Inlet.
Ordinary Order By will put Île at the end of the list. I finally came up with using nativeQuery and sort the data using database engine's function (in oracle is about using NLS_SORT)
But I am tight with database engine and version, so for example if I change my database to postgres then the application will break. I was looking for native JPA solution (if exists) or any other solutions.

To archive this, without use native query JPA definition, I just can see two ways:
Create a DB view which includes escaped/translated columns based on DB functions. So, the DB differences will be on the create view sentence. You can define a OneToOne relation property to original entity.
Create extra column which stores the escaped values and sort by it. The application can perform the escape/translate before store data in DB using JPA Entity Listeners or in the persist/merge methods.
Good luck!

Best method to archive data using Hibernate

I have a two tables chart and chartHistory which has similar table structure
chart_id NUMERIC(9,0)
chart_ref_id NUMERIC(9,0) NOT NULL
chart_property VARCHAR2(20) NOT NULL
chart_value VARCHAR2(100)
The entries in chart needs to be stored into the chartHistory table, when we get new property/value pairs for chart reference id.
I am planning to implement it using Hibernate in the following way
Get the list of values from CHART table using the chartReferenceId
List<Chart> chartList = chartDao.findChartByVisitRef(chartReferenceId);
( named query : findChartByRef = from Chart chart where chart.chartReferenceId=:chartReferenceId)
Use the retrieved list and build a chartHistoryList using the values from chartList and call the Hibernate method saveAll
chartHistoryDao.saveAll(chartHistoryList);
Once saved, remove the existing entries from the CHART table.
chartDao.deleteAll(chartList);
Build a newChartList for the new entried received, and do a hibernate saveAll
chartDao.saveAll(newChartList);
As you can see this executes four queries ie. for retrieving old records, saving them into the archive table, deleting the old entries and inserting the new values.
I would like to know whether there is a better way to implement this? Something of the sorts insert into .. (select from... ) would be more efficient I guess? Please advice.

Try the envers/audit module of Hibernate which handles all this for you automatically.
The main problem with envers/audit right now is to find the documentation. Envers (the original module) is supposed to be merged with Hibernate code since 3.5 but the core documentation doesn't mention anything about versioning or auditing even though InfoQ insists "Hibernate 4.1 Released With Improved Auditing Support"
So try the outdated documentation linked from the obsolete envers page and hope for the best.
Disclaimer: I haven't used Hibernate or envers for years.

How to accomplish CRUD operations on dynamic forms?

I have followed Balusc's 1st method to create dynamic form from fields defined in database.
I can get field names and values of posted fields.
But I am confused about how to save values into database.
Should I precreate a table to hold values after creating form and
save values there manually (by forming SQL query manually)?
Should I convert name/value pairs to JSON objects
and save?
Should I create a simple table with id,name,value field and
save name/value pairs here (Like EAV Scheme)?
Or is there any way for persisting posted values into database?
Regards

It look like that you're trying to work bottom-up instead of top-down.
The dynamic form in the linked answer is intented to be reused among all existing tables without the need to manually create separate JSF CRUD forms on "hardcoded" Facelets files for every single table. You should already have a generic model available which contains information about all available columns in the particular DB table (which is Field in the linked answer). This information can be extracted dynamically and generically via JPA metadata information (how to do that in turn depends on the JPA provider used) or just via good 'ol JDBC ResultSetMetaData class once during application's startup.
If you really need to work bottom-up, then it gets trickier. Creating tables/columns during runtime is namely a very bad design (unless you intend to develop some kind of DB management tool like PhpMyAdmin or so, of course). Without the need to create tables/columns runtime, you should basically have 3 tables:
1 table which contains information about which "virtual" DB tables are all available.
1 table which contains information which columns one such "virtual" DB table has.
1 table which contains information which values one such column has.
Then you should link them together by FK relationships.