We are using FluentMongo and now that LINQ support has been added into the C# driver, we are going to remove the dependency on Fluent and go with the official C# driver alone.
Has anyone done this already, and was it simple and straightforward? Is there anything we need to be looking out for?
Hopefully others will report back to you as well, but as the implementer of the LINQ support in the 1.4 C# driver I can tell you a bit about what to expect.
Overall you can expect some features to be missing and some new ones to be present. One difference is that the official C# driver only supports LINQ queries that can be mapped to reasonably equivalent MongoDB queries. The FluentMongo library would handle some LINQ queries that didn't have MongoDB equivalent queries with techniques like building Javascript where clauses or dynamically building map/reduce jobs. The official C# driver is not going to do that, because we don't want deceptively simple looking LINQ queries to have unexpectedly inefficient implementations.
In the future we are looking at mapping certain types of LINQ queries onto the new aggregation framework coming in the 2.2. release of the server.
If you run into any issues porting to the 1.4 C# driver please report them at https://jira.mongodb.org/browse/CSHARP and we will look at them as quickly as possible.
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I am new to Scala as well as play framework with Scala 2.0. I like the idea of writing the SQL code myself and have full control rather than depend on ORM tool. But does Anorm SQL work across different database vendors like MySQL and Oracle? Since I am writing an application which should be capable to work with any Relational database, my requirement is to write SQL which should work across databases since my application should work with vendor database.
Some vendor might have Oracle and some might have MySQL. So my code should be DB agnostic.Is this possible in Scala as I know that quires which run on mysql will not run on Oracle.
Thanks in Advance,
Pradeep
Short answer: NO.
Long answer: Anorm is just a library for dispatching your SQL queries to the database through JDBC, retrieving the results and delivering them to you. It does not understand the differences between different databases because it relies on JDBC for connection handling, and on you for writing queries.
You either have to handle different DB engines yourself or have an ORM handle that for you.
PS: Unless you really need to have a DB agnostic application (and fully understand its implications), I'd suggest you simply target 2-3 popular engines and avoid the future complications.
since my new project has to use toplink-essentials which only supports jpa 1, I'm looking for some good jpa-utilities. So far I only worked with jpa 2 (both EclipseLink and Hibernate), which didn't need any utilities to write dynamic queries in 99% of the time.
Now I'm stuck with jpa 1 and wondered if there were some utilities/libraries which could support me in writing my queries a little bit more dynamically.
Jonny
TopLink Essentials does support Expression queries which are similar to JPA 2 Criteria. You may be able to use them.
You should also be able to upgrade your server to EclipseLink.
I have recently started getting familiarized with NoSQL (HBase). I am definitely a noob.
I was investigating about ORMs and high level clients which can be used on HBase and came across a few.
Some ORM libraries like Kundera are providing SQL like data query functionality. I am finding this a little counter intuitive.
Can any one help me understand why we would again need SQL like querying if the whole objective was to move away from it?
Also can anyone comment on your experiences with ORMs for HBase? I looked at a few of them from http://wiki.apache.org/hadoop/SupportingProjects and started looking at Kundera.
Another related question - Does data query with Kundera run map reduce jobs internally?
kundera or Spring data might provide user friendly ORM layer over NoSQL databases, but the underlying entity model still has to be NoSQL friendly. This means that NoSQL users should not blindly follow RDBMS modeling strategies but design ORM entities in such a way so that all NoSQL capabilities can be used.
As a thumb rule, the kundera ORM entities should be designed using query-first strategy where first the queries need to defined so as to create primary keys and also ensuring that relationship model is used as minimal as possible. Querying on random columns and full scans should be avoided and so data might have to be replicated across entities for reducing multiple entity look ups. Also, transactions management needs to be planned. FYI, kundera does not support transactions(beyond single row TX supported by Hbase/Cassandra).
Reason for using Kundera:
1) If looking for SQL like support over HBase. As it is build on top of HBase native API, so it simply transforms these SQL queries in to corresponding GET or PUT method calls.
2) Currently it support HBase-0.20.6 only. Kundera-2.0.6 will enable support for HBase 0-90.x versions.
3) Kundera does not do sometihng out of the box to provide map reduce over SQL like queries. However support for such thing will be provided in Kundera-2.0.6 by enabling support for Hive native queries only!
It is totally JPA compliant, so no need to learn something new. It simply hides complexity at developer level with very minimal effort.
SQL like querying is for developement ease, quick developement, less error prone and reusability ofcourse!
-Vivek
The comment here says I can use LightSpeed, which I've downloaded and installed. Then I get to this screen:
And I'm not sure what to do. I'm not too familiar with connection strings, first of all. I found this, but... I think "Model assembly" and "Unit of work class" are required. I don't have any DLL's and I'm not working with LightSpeed models, so I'm not sure this is even useful.
The IQ addon Driver works great with my MySQL database. Really easy to set up and use. Are there any drivers that work with PostgreSQL yet? Looks like you can add them by choosing an "*.lpx" file.
I've developed a dynamic LINQPad driver for PostgreSQL databases. Using it you can query the database without the necessity to define your model first (similar to the IQ or the built in LINQ to SQL driver).
You can find it on GitHub:
https://github.com/fknx/linqpad-postgresql-driver
The LightSpeed driver is a static driver, meaning that you must first create a model (and hence a typed DataContext) using the LightSpeed tools.
If you just want to query PostgreSQL in LINQ, you need a dynamic LINQPad driver which no-one has written has yet, AFAIK.
I searching to migrate my cms from SQL to NoSQL MongoDB using C#. I have created the first classes migration but i'm not happy with future evolutivity and stability using currents C# drivers. I have stated with Samus, moved to Norm and now mixed with Official mongodb driver. Can someone sugest what preserve in Norm driver and what use with official driver and when we can imagine to get a complete driver to stabilize the developments.
thanks.
Consider using 10gen (official) driver for MongoDB, since it has been heavily refactored, tested and is currently maintained.
Norm driver is being phased out in favour of official driver
Updating numerical types using NoRM and other tools changes numerical type metadata on MongoDb
On the top of 10gen driver you can add if really need FluentMongo.