About comparison
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] ...
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 ...
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 ...
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 ...
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 ...
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. ...
JPA Criteria API Queries
Explains how to use the JPA Criteria API (CriteriaBuilder, CriteriaQuery, etc.) to build JPQL like queries.... See JavaDoc Reference Page... ). Comparison expressions ( equal size(collection) ...
[ODB1] Chapter 7 - JDOQL Queries
Explains how to use JDOQL, the Java/JDO Query Language.... object in other operations, such as method calls and comparison expressions. Fields Persistent fields of the candidate class ... fields can participate in queries in combination with comparison expressions, as in "this.age >= 18" . The this. prefix ...
Literals in JPQL and Criteria Queries
Describes literals in JPQL, including null, false, true, numbers, strings, dates enums and types.... NULL , null and Null are equivalent. Notice that comparison with NULL in JPQL follows the SQL rules for NULL comparison rather than the Java rules, as explained in the Comparison ...
Paths and Types in JPQL and Criteria API
Explains how to use object expressions (path navigation, type) in JPA/JPQL.... user defined persistable classes can participate in direct comparison using the = and <> operators. But more often they are ... and for numbers ), they can be compared by all six comparison operators , and they can be used in ordering . This ...
