Are there any known issues of EF usage with Oracle database? Are there any key points I should specially pay attention? Share your toughts and experience please?
Devart dotConnect for Oracle allows you a direct access to the Oracle database without Oracle client installation.
You will need to use a 3rd party EF provider to talk to Oracle, this may cost money.
All of the EF examples asume you are using Sql Server
Most EF implementations for Oracle require the deployment of the Oracle client in order to use some or all of the available features. Look for an implementation that is 100% managed for support of all features in order to avoid the performance bottlenecks, memory leaks, and deployment headaches this type of implementation can cause.
Related
I am developing some integration software for a client using amongst other things, C#, NServiceBus and Oracle 10g (client and server). The requirement is that I need to develop a new plugin for NServiceBus to create an implementation of ITransport which is the queuing mechanism for the messages. So Oracle Advanced Queuing is used for this. I have done quite a bit of work writing code for advanced queuing in Oracle 11g (client and server), but looking at ODP.Net 10g it seems that the queuing support is lacking or non-existent so that may prove to be problematic.
My question is this:
I know that you can use the 11g client against a 10g database server, but is it a good idea for Oracle Advanced Queuing and are there any gotchas I need to know about?
Many thanks.
Is it a good idea for Advanced Queueing? Well, I don't see why not, since 11g client connecting to 10g server is supported.
I don't imagine that AQ would pose any unique problem, specific to AQ. If you think about it, AQ is just PL/SQL calls that interact with tables under the covers. There's really nothing different at the client side, than there is with any other Oracle code.
So, I say go for it. But, as always: Test, test test. And then test some more.
But, in principle, I don't see a problem.
You may want to check out the NServiceBus-Contrib project, as there is an AQS transport there for 2.x.
I need to develop a program that must delete and insert data into an Oracle database. Is it possible to use LINQ to SQL with Oracle?
For development I use MS SQL server but it will be a Oracle database in production. What do you recommend?
Officially No. Linq to SQL was originally build with the ability to swap out the data provider to allow connections to other databases, but they disabled this functionality in the released versions to encourage people to use more stable and supported data access layers (like EF). The recommended approach is to use Entity Framework if you want to switch between SQL and Oracle.
Also, Patrick is very right, make sure you are developing and testing against the same database platform you are going to use in production, there is a world of difference in how they operate. Sure, you should be able to abstract it away to not care about whether you are using SQL or Oracle, but that is almost never really the case.
No, you can't. Although LINQ to SQL was initialy designed with multi-database support in mind (you can see this when looking at the code using .NET Reflector) using a provider model, this model was never made public and Microsoft has no intensions in adding multi-database support to LINQ to SQL.
If you need multi-database support, please use Entity Framework.
No, LINQ-to-SQL doesn't support Oracle. Internally, the project had support for multiple back-ends, but this never made it into the final public release. I believe LINQ-to-Entities supports other databases.
i am looking for an Delphi component to connect to an ORACLE database server in an direct way without install the oracle client.
i knew the Oracle Data Access (ODAC) from DevArt. there are any other component with this capability?
ODAC offers two connection modes to
the Oracle server: connection through
the Oracle Call Interface in Client
mode and direct connection over TCP/IP
in Direct mode. ODAC-based database
applications are easy to deploy, do
not require installation of other data
provider layers.
Thanks in advance.
No, there is no other Delphi Win32 libraries allowing to connect to Oracle without the installed Oracle Client. And, IMHO, that is correct, because:
OCI (Oracle Call Interface) is quite complex piece of software. I will say, it is most complex closed sourced DBMS Call Level Interface in the World. And it is changing from version to version. Oracle has official rule - the Oracle Client v X supports Oracle Server v X-1 ... X+1. Because even such company as Oracle, dont want to spend resources to support and test all the protocol nuances across all possible versions. So, I dont think, that DevArt ever will implement 99.9% stable Oracle SQL*Net protocol implementation. And the INet posts proof that ...
AFAIK, the ODAC Net mode does not support some of the Oracle Client important features and has some important limitations. Although it works well for simple data access scenarious.
If you will purchase Oracle support, then it will decline all your support requests, if they will know, that you are not using official client software. That is just Oracle rule.
If you dislike to install and tune the full scale Oracle Client, then you can just use Oracle Instant Client. Which does not require install or setup procedure. And you will be in safety in case of the different data access scenarious and Oracle Server versions.
PS: Although I may be considered as a biased person :)
There is also Allround Automations Direct Oracle Access, it do require Oracle SQL*Net or Net8. but is a brilliant component suite.
The only solution I found is ODAC, and it's working very nice, I have been using it since years without getting any problem with the direct mode.
there's some limitation with the direct mode, but most of users will not get these limitations with their application.
We have a client that has Oracle Standard, and a project that would be ten times easier addressed using OLAP. However, Oracle only supports OLAP in the Enterprise version.
Migration to enterprise is not possible
I'm thinking of doing some manual simulation of OLAP, creating relational tables to simulate the technology.
Do you know of some other way I could do this? Maybe an open-source tool for OLAP? Any ideas?
You can simulate OLAP functionality using client side tools pointed at a relational database.
Personally I think the best tool for the job is probably Tableau Desktop. This is an amazingly sophisticated front end analytics tool that will make your relational data look multidimensional without much effort, and the tool itself is really mind blowing. They have a free trial so you can take it for a spin. We use Tableau heavily for our own analysis and have been very impressed. Of course, this tool also works with multidimensional databases as well, so if you end up with some cubes at the end of the day you can continue to use the Tableau front end.
As for open source, you could try out Palo - an open source MOLAP server and Excel front end.
If you are interesting in building your own reporting front end and use .NET there are a number of components (such as the DevExpress PivotGrid or the several tools from RadarSoft) that will do the same thing, but will require some elbow grease to get wired together.
I find that it's the schema that causes most of the issues people have with querying a database. OLAP forces you to either a flat table or a Star/snowflake schema which is easy to query and comparably faster to the source oltp tables. So if you ETL your source to a flat table or star schema you should get 80% of what you get from OLAP, the 20% being MDX and analytic functions and performance.
Note that you should get a perf boost with a star schema in relational database as well and Oracle probably has analytic functions in PL/SQL anyways.
Try an open-source OLAP server called 'Mondrian'. IIRC the XMLA API on this is sufficiently compatible with AS to fool Pivot Table Services, which would allow you to use it with ProClarity or Excel.
IIRC it was originally designed to work over Oracle - it is a HOLAP architecture using base tables in the underlying relational store and caching aggregates. You can also make use of materialised views and query rewrite in the underlying Oracle database to do aggregates.
A few more thoughts on this topic:
Actually, Oracle Standard does have an OLAP facility based on a descendent of Express embedded in the database engine and storing its internal data structures in BLOBs in the main tablespaces. Using this is technically possible but not necessarily advisable for the following reasons:
It uses a highly non-standard OLAP query engine with very little third party tool support (AFAIK ArcPlan is the only third-party OLAP front-end supporting 10g+ OLAP), poor documentation for the query language and almost no third party literature describing it. This will work with B.I. Beans if you feel like writing a JSP front-end. It is not compatible with MDX at all. As of early 2006 the best Oracle could do when asked about drillthrough (this functionality was not supported in Discoverer 'Drake') was to recommend building a JSP apllication using B.I. Beans.
The reason that there is no migration path from Standard to Enterprise is that Enterprise is actually what used to be Siebel Analytics. Standard is the old Oracle OLAP/Express descendant which Oracle partners recommended avoiding even before Oracle bought out Seibel. Oracle has not even attempted to support migrating.
From this point of view, Mondrian is actually the most cost-effective OLAP solution for an Oracle Standard Edition shop. You can get a supported version from an outfit called Pentaho1. The next cheapest is Analysis Services, which comes with SQL Server. Following that you are into the likes of Hyperion Essbase, which will be an order of magnitude more expensive than SQL Server or any supported verion of Mondrian.
Whilst MS SQL Server offers OLAP, you'll need an Enterprise licence to use a cube in a live environment that is web-facing.
You might want as well to give a try to www.icCube.com - we're quite flexible on the data-source used to populate the cube and are quite cost effective compared to the big actors of the market.
I can connect with the DataContext to the Oracle database however I get errors in running the query against the oracle database. I looked at the SQL generated and it is for MSSQL and not Oracle PSQL.
Does anybody know of a decent easy to use wrapper to use LINQ against an Oracle Database?
No, LINQ to SQL is very much MS SQL only - think of it as a client driver.
Microsoft is/was helping Oracle and DataDirect develop providers for Oracle and other non-MS database servers.
We use the OraDirect driver from Devart. It includes ADO.NET Entity framework support. You can download a trial version here. You may then use LINQ to entities or entity SQL on top of this.
The pricing of this is quite developer friendly, you pay per developer seat and you may use it however you like.
Another big advantage of this driver is that you can use it without installing an Oracle client, this is a big plus and worth the price alone.
#Greg: We evaluated the datadirect drivers as well, but the performance was poor and cost astronomical.
Edit: It seems DevArt announced a beta with LINQ support recently
One thing you might look into is that there is now LINQ to Entities, which leverages the MS Entity Framework, which I believe is DB agnostic. I'm still looking into how it works myself, but if you could create an ADO.NET Data Entity that interfaces with Oracle, you could then use LINQ against that Entity.
There's also Lightspeed which has a per-organization (not per-developer) license scheme and seems to have a pretty solid documentation library and a free trial version (up to 8 entities). I'm checking this out presently.
After a long search I found DbLinq and should do the trick. I am going to try it myself. I came across your question because I was searching for the same solution. Hope it helps.
Do look at Linq to entities though. I have a datareader populate a collection of objects that are mapped to the oracle table. I can use linq to query that collection in very powerful, simple, and easy ways. I love it. Highly recommend.
Try Devart LinqConnect. This product allows you to work with Oracle, etc.
Why not try ALinq ？ http://www.alinq.org
Look in codeplex:
Linq To Oracle project
Not an easy way, at least until a good provider is produced.
Really MS should provide at least an OLEDB Linq provider. After all, Linq to Sql is basically an implementation of IQueryable with designer support.
Another cross-database solution that works fairly well across Oracle, SQLite, MySQL and SQL Server is eXpress Persistent Objects