I am wondering how to effectively use an EJB query in the following situation.
I have 2 tables. Each table has a corresponding @Entity java class.
| TableA
| ---------
| int tableAPrimaryKey
| varchar(20) tableAField
| ...etc, plus many more fields
|
| TableB
| ---------
| int tableBPrimaryKey
| int tableAForeignKey
| varchar(20) tableBField
| ...etc, plus many more fields
|
I would like to run a query that gets each row from Table A, and a count from
Table B (dependant on tableAForeignKey). So for each row my html output would
look something like this:
"tableAField1", "tableAField2", "tableBCount"
Using EJB, I can get each row of TableA by running:
| Query q = em.createQuery("from TableA o ");
| return q.getResultList();
|
Using EJB, I can get a count for each row of TableA from TableB
| Query q = em.createQuery(
| "select count(o) " +
| "from TableB o " +
| "where o.tableAForeignKey = :currentRow"
| );
|
Is there a better way to do this using EJB? Looping through each result of
Table A and executing a count query seems pretty inefficient.
The correct way seems to be to create a native query and manually build all
these objects. This is extremely tedious as there are a lot of columns in both
tables that are needed.
Are there any suggestions of a better way to do this using EJB?
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