Comments (6)
Anyone have thoughts on this? I have the code ready to rock and will send a pull request soon
from sql2o.
I agree that sql2o really needs a way to lazy-fetch from the database with a cursor while the connection is open, but I have never concluded how best to implement it.
I'm really curious how you solved it! How do you make curtain that the connection is closed after use?
from sql2o.
Well, you cannot make certain that the connection is closed after use, because exposing an iterable means you have no idea when someone will stop iterating. You cannot simply close the connection when iterating completes, because someone might only pull out 1000 results then decide to stop iterating. I believe the best you can do is make it easy to figure out for a developer that wants to use lazy functionality.
You can see what I did here: https://github.com/aldenquimby/sql2o/blob/master/src/main/java/org/sql2o/Query.java#L274
You can see Java 6 usage by looking at the executeAndFetch
method in the link above.
Basic Java 7 usage would look like this:
try (ResultSetIterable<MyClass> rsIterable = query.executeAndFetchLazy(MyClass.class))
{
for (MyClass obj : rsIterable)
{
// do work here, maybe flush 1000 results at a time or something
}
}
from sql2o.
Wow, that is a way better solution that I had in mind. This is indeed a very valuable addition to the project! If you create a pull request, I will happily merge it in, and release a new version soon.
from sql2o.
Ok great! I will add a few more tests before submitting a pull request. Also I would like to move ResultSetIterator
to another file (so that it isn't a subclass of Query
), but then I wouldn't have access to the method getRSVal
.
Could I move this to some sort of utility class? Or do you think I should just leave the iterator as an inner class of query?
from sql2o.
You could perhaps change the accessibility of the getRSVal
method to be package internal, and move the ResultSetIterator
to a new class in the same package.
Alternatively the getRSVal
method could be moved to a utility class in the tools
package and made public.
Either way, I think it is best to get it out of Query
from sql2o.
Related Issues (20)
- When in jar file I receive No suitable driver for error HOT 1
- Publish version 1.6.0 of oracle extensions
- sql2o can't rolback ? HOT 3
- can i change the Type of return value of executeAndFetch()
- State of the Project
- NPE when return query object is of type Map HOT 1
- How to correctly insert with array type (ex bigint[]) columns?
- Library uses now-private reflection mechanism HOT 2
- Can't add ON DELETE CASCADE to forein key when creating table, using PostgreSQL. HOT 1
- Updated MySQL 8.0.26 connector breaks historically working code HOT 2
- Next release HOT 2
- MethodSetter setProperty failing with generic IllegalArgumentException
- Failed test testAllTypes(org.sql2o.reflect.ReflectionFieldSetterFactoryTest) only in Maven HOT 2
- Collection of enums is not properly mapped to query params HOT 1
- SQL2o 1.6.0 Compatabile with JDK 17/ OpenJDK 17 ? HOT 1
- SQL with ? for parameters HOT 4
- Retrieving List<Long> from query HOT 2
- Query.withParams upgrade HOT 2
- Javadoc has an issue with the CDN HOT 1
- In v1.7.0, kotlin data class is no longer recognized as pojo HOT 1
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from sql2o.