I used jooq when found no similar to mybatis page plugin or similar spring data pa paging. Will jooq have it? If not, then trouble giving a good solution, thanks!
jOOQ supports SQL style offset pagination through LIMIT and OFFSET as documented in the manual here:
https://www.jooq.org/doc/latest/manual/sql-building/sql-statements/select-statement/limit-clause
Alternatively, you might also want to look at jOOQ's built-in keyset pagination support, which is often the better choice:
https://www.jooq.org/doc/latest/manual/sql-building/sql-statements/select-statement/seek-clause/
https://blog.jooq.org/2016/08/10/why-most-programmers-get-pagination-wrong/
Related
Since JOOQ 3.6+, they no longer ship with SQL 2 jOOQ Parser. Search on the internet, I can't find the tool SQL 2 jOOQ Parser anywhere.
Just wonder is there any similar tool like SQL 2 jOOQ Parser so we can generate the JOOQ code from native sql?
There's a feature request for this:
https://github.com/jOOQ/jOOQ/issues/6277
From the feature request:
This was already implemented in the past by the https://github.com/sqlparser/sql2jooq third party module, but it suffered from several flaws:
It didn't produce very good jOOQ code
It worked only for MySQL and PostgreSQL
It depended on a third party parser (by Gudu Soft), which was proprietary and not under our control
It was hard to use
The product got zero (!) user feedback over quite some time, which is never a good sign.
Eventually, we'll re-iterate the idea, but it's a lot of work, and there are probably more interesting things that can be done first. The approach most people will choose when writing jOOQ queries is they:
Choose a test driven approach where the feedback cycle is tight, such that executing a query to test if it's correct is done relatively easily
Use views (seriously, use views! Why don't people use views more often?) for your very complex static SQL and query the views from jOOQ
AFAIK, the Pageable class supports only LIMIT/OFFSET based paging. However, while being a quite universal solution, it comes with some downsides as outlined here https://momjian.us/main/blogs/pgblog/2020.html#August_10_2020
Keyset Pagination (aka Seek Method or Cursor-based Pagination) has some benefits in terms of performance and behavior during concurrent data inserts and deletes. For details see
https://use-the-index-luke.com/no-offset
http://allyouneedisbackend.com/blog/2017/09/24/the-sql-i-love-part-1-scanning-large-table/
https://slack.engineering/evolving-api-pagination-at-slack-1c1f644f8e12
https://momjian.us/main/blogs/pgblog/2020.html#August_17_2020
So, are there any plans to support this pagination method, e.g. via Pageable<KeyType> and getKey() that then gets incorporated into the SQLs WHERE clause?
This possibility was discussed in the team and while not considered urgent it is something we would like to offer eventually.
The first step would be to provide support for this in Spring Data Commons, i.e. a persistence store independent API. The issue for this is DATACMNS-1729
I am aware of what Field.store and Field.Index means in Lucene document and aware of the use-cases when either Field.store or Field.Index is set to NO.
But recently, I came across piece of code, when both are set to NO. Could anybody explain the use-case with an example, when we need to set them to NO ?.
PS: I referred to this SO question, which explains why one is set to NO and another is set to Yes, with good use-cases, but it doesn't give answer to my question.
Lucene is the generic full-text indexing and search library and its not the framework in itself like ElasticSearch or Solr.
So, if you are developing your search application and directly using Lucene then you have full control over which fields to index and/or which fields to store from your app in the Lucene inverted index.
Frameworks like ElasticSearch or Solr which are built on top of Lucene, may use a schema for indexing or it might be schemaless too.
I think in cases where it's schemaless, it makes sense to explicitly ignore the fields which we don't want to index and store both.
Is there any place where we can find code samples for different features (at least for most used methods) of CassandraTemplate ?
The best place I know is the source code, here: CassandraOperations is the code for the interface.
You can also look up its test classes to see the methods in action.
In the below link, Linq-To-Sql produces a range of methods to get data back based on various real-world needs (e.g. recent topics, etc).
How can I get Subsonic to produce me a set of classes which would interrogate and return data back from my data source in such a way? I get classes which really just present CRUD ops.
Thanks
I don't see a link here but in general I'd say you can use SubSonic 3 in much the same way you can Linq to Sql. Here's some sample code:
http://subsonicproject.com/docs/Linq_Select_Queries
Other than that I'd need more specific examples.
The way I would do it with SubSonic is to make a view with the way you want the data to be formatted, and then retrieve it with SubSonic.