About comparison

manual

Comparison in JPQL and Criteria API

Explains how comparison operators can be used in JPQL queries, including in comparing null values. Most JPQL queries use at least one comparison operator in their WHERE clause. This page covers the following topics: Comparison Operators Comparing NULL values IS [NOT] ...

 
faq

Is ObjectDB better than competitive object databases?

... the following points when doing your own objective comparison of object databases: ObjectDB is unique in supporting the ...

 
faq

What are the main benefits of using ObjectDB?

By using ObjectDB you can reduce development time and costs and improve your application performance. Reducing Development Time and Costs ObjectDB makes database programming easier and faster. The ability to store ordinary objects in the ...

 
manual

JPA Query Expressions (JPQL / Criteria)

Describes JPA query (JPQL / Criteria API) expressions (literals, operators and functions).... + (addition) and - (subtraction). Comparison operators : =, <>, <, <=,>, >=, IS [NOT] ... Collections in JPQL and Criteria Queries Comparison in JPQL and Criteria API Logical Operators in JPQL and ...

 
forum_thread

java.sql.Date equals comparison not working with CriteriaAPI

Hello, Using ODB 2.4.5 and the Criteria API, doing a simple equals comparison with java.sql.Date value doesn't match any results in the database. Our code looks like this: ... ODB 2.4.5 and the Criteria API, doing a simple equals comparison with java.sql.Date value doesn't match any results in the ... also in the Entity property field to ensure pure date comparison and saving without time parts so this is made sure. thanks ...

 
forum_thread

ObjectDB vs DB4O comparison

ObjectDB and DB4O are the only two real object database I known. Why didn't you give a comparison between them in JPA Performance Benchmark (JPAB)?  TIA ... real object database I known. Why didn't you give a comparison between them in JPA Performance Benchmark (JPAB)?  TIA ...

 
forum_thread

String comparison in query where clause

I am having trouble getting a simple string comparison to work in an SQL "where" clause.  It is my understanding that queries are case sensitive by default and I do not want that, so I am constructing the query as follows... SELECT e FROM Exercise AS e WHERE UPPER(e.name) = ?0 and then I am converting the parameter (representing by position ?0) to upper case.  I am certain the parameter value is correct, and there should be a matching record in the database, but my query returns no result. ... I am having trouble getting a simple string comparison to work in an SQL "where" clause.  It is my understanding that ...

 
forum_thread

Java 6/7 Performance Comparison

Hey, I've been using ObjectDB for a small scale home project to gain some familiarity before proposing it in a commercial project at work. What I've noticed though is that when using objectdb in embedded mode based on the console tutorial, there seems to be a bit of a performance gap running the same code between Java 6 & 7 Tracing it through I can see the bottle neck seems to be at the creation of the entity manager and I was wondering if there are any additional configuration options I may have missed while running under java 7. #1 2014-03-06 14:31 Hey, I've been using ObjectDB for a small scale home project to gain some familiarity before proposin ...

 
forum_thread

Create simple index for a Id field

Hello, I just wanted to write another anotation to my key field so I can have a really simple index. This is the original code: @Entity public class ObjectDbEntity<Key,Value> implements DataItemProvider<Value> {         @Id     private Key key = null;     private Value value = null; and I just want my key to be indexed on my db, just like this: ... but also in retrieval and reading operations (see this comparison ). But obviously a HashMap in memory is faster than any DBMS ...

 
forum_thread

in-memory and on-disk support?

I've had a quick read through the features/FAQ and haven't been able to find a clear answer. I'm looking at replacing a setup of H2 where I have 40GB in-memory backed by 800GB on-disk, the 40GB in memory represents the first 40GB of the 800GB on-disk for super-fast recent entry searching, the records at the end continuously purge as the new ones come in(duplicate write, one to in-memory and one to on-disk). ... file system overhead is minimal. See for example comparison of RAM drives , including against a regular hard disk. ...