I'm writing an application that should be able to query different databases from different vendors (Oracle, Sybase, SQL Server, MS Access).
Is there any tool that performs this for C# or VB.Net ? something like UnityJDBC ?
I would like to avoid creating different interfaces that communicate with different SQL structures to query databases.
Thanks
Nothing is built into .NET out of the box. However, simple web searches proves that it is possible to use LINQ to all of these
Oracle: http://download.oracle.com/oll/obe/EntityFrameworkOBE/EntityFrameworkOBE.htm
Sybase: http://www.sybase.com/detail?id=1056609
Access: http://forums.asp.net/t/1542443.aspx
SQL Server (there are a lot of resources, here's a comprehensive one): http://www.codeproject.com/Articles/215712/LINQ-to-SQL-Basic-Concepts-and-Features
Related
Does anyone have experience building database reports - doesn't matter which database - i just want design ideas - for a system that is made up of many separate, but identical databases?
I cannot "combine" all databases into one. They must be separate.
But the structure is identical across all databases...
I need to build a web interface that will allow a user to get a "global" report that will query all databases and build one combined report.
Do you have any comments on how the model would look like? or anything you think i need to beware of?
Thanks.
I don't have first hand experience with cross database reports, my experience comes from a product the company i work for sells which can create reports from multiple databases, from your description i believe you require something of the "combine" tables kind, in this case i recommend you to detect the tables used in the query, and unify them in a single temporary intermediary database, for example Access, SQL Server CE or SQLite and then run the query against this temporary database or table.
If your databases are Microsoft SQL Server, then using SQL Server Reporting Services seems like a good solution. The software for the report generation / display is bundled along with the database software.
It gives you a web interface, where you can configure 'data sources' from any number of remote databases, and combine data from these sources into reports. It is user friendly and you can do all the report design / configuration through the web interface without having to write any code.
some references :
Building report using SQL Server stored procedure
http://blog.hoegaerden.be/2009/11/10/reporting-on-data-from-stored-procedures-part-1/
Is there seriously no way of using a shared access non-server driven database file format without having to use an SQL Server? The Entity Framework is great, and it's not until I've completely finished designing my database model, getting SQL Server Compact Edition 4.0 to work with Visual Studio that I find out that it basically cannot be run off a network drive and be used by multiple users. I appreciate I should have done some research!
The only other way as far as I can tell is to have to set up an SQL server, something which I doubt I would be able to do. I'm searching for possible ways to use it with Access databases (which can be shared on a network drive) but this seems either difficult or impossible.
Would I have to go back to typed DataSets or even manually coding the SQL code?
Another alternative is to try using SQL
Install SQL Server express. Access is not supported by EF at all and my experience with file based databases (Access, SQL Server CE) is mostly:
If you need some very small mostly readonly data to persist in database you can use them (good for code tables but in the same time such data can be simply stored in XML).
If you expect some concurrent traffic and often writing into DB + larger data sets their performance and usability drops quickly. They are mostly useful for local storage for single user.
I'm not sure how this relates for example to SQLite. To generate database from model for SQLite you need special T4 template (using correct SQL syntax).
Have you tried SQLite? It has a SQL provider, and as far as I know EF supports any provider. Since it's file-based, that might be a plausible solution. It's also free.
I'm relatively new to .NET but I'm trying to determine if it's possible to have a single .NET 4 application connect to multiple vendor databases simultaneously (SQL Server, Oracle, DB2 and MySQL) using ADO.NET and execute queries simultaneously?
All the examples I've found so far talk about connecting to only one database at a time.
Thanks!
You just need 4 connections strings and 4 separate ADO Connection objects. And then what SLaks said about async queries to do them simultaneously, if you truly want them running in parallel.
You can execute two queries the same way you execute one query.
If you want them to execute two queries at once, you'll need to make asynchronous queries or use threads.
The ADO.NET framework defines an abstract set of 'DbXXX' classes like DbConnection,DbCommand etc, which are implemented by various database providers such as
System.Data.SqlClient.SqlConnection' in the System.Data.dll for Sql Server
'Oracle.DataAccess.Client.OracleConnection' in the Oracle.DataAccess.dll (ODP.NET provider) for Oracle
'MySql.Data.MySqlClient.MySqlConnection' in the MySql.Data.dll for MySql etc
You then need to design your apllication against the abstract set of classes and use appropriate implementations wherever required. Most of the queries should work against all the backends but there will obviously be backend specific tweaks, not to mention stored procedure calls.
Alternatively you could use an ORM (Entity Framework, Telerik OpenAccess ORM, NHibernate etc) and abstract much of this difference to the ORM. Although I am not sure you can use a single entity model (in EF) against multiple backends.
We have a SharePoint 2007 site. It is supported by two back-end databases - one hosted on SQL Server, another on an open-source RDBMS. We issue CAML queries to retrieve data from SQL Server, and ADO.NET queries to retrieve data from the other server. Our architect says we would be better off if we used the same approach (namely, CAML) to get data from the both databases.
Is it possible to use CAML queries to retrieve data from any RDBMS other than SQL Server?
If so, please suggest any web resources, docs, anything you find appropriate.
CAML (at least that part used for SPList.GetItems queries) seems to be quite simple, so translating it into valid SQL statements should not be too complex. Which means, you could create a "translator module" and issue your queries against it. For instance, you can follow guidelines published in the article "[Implementing a .Net Framework Data Provider](http://msdn.microsoft.com/en-us/magazine/aa720164(VS.71).aspx)".
I'm developing an asp.net application with Database factory pattern which allows the application to support both Sql Server and Oracle. I've created an abstract class that has the methods common to Sql Server and Oracle, like the CreateConnection and CreateCommand methods. This class is implemented by SqlServer and Oracle classes. Now, is there an easy way to write in-line sql queries with parameters common to both Sql Server and Oracle. I mean, I understand that we use "#" symbol in Sql Server and ":" in Oracle for parameters. Just for this reason, I'm writing queries twice in each of the class. Is there a way to write such queries common to both the databases? (or interpret the parameters from one common query?)
Thanks.
The only way to write one query that will work for both Oracle and Sql Server is to use only the syntax that is common to both platforms. Once you use features that are different between the two languages (like parameters or joins), you either have to write two different queries or hack together a "translator" class that converts a query from one platform to the other.
I've done a lot of this type of programming (database-agnostic software), and with .Net a relatively pain-free way of doing this is to write your main application to work entirely with ADO.Net DataTables/DataSets, with a wrapper class that handles generating the DataTables from either Oracle or Sql Server tables under-the-hood, and also handles persisting changes made to the DataTables back into Oracle or Sql Server. This approach isolates your DB-specific code in one place, although it's not necessarily a viable approach if the data your application needs access to is large.
You could write some kind of translator, but I would suggest that in some cases you'll need to write db-specific code for performance reasons anyway, so you'll have to put up with the maintenance burden of two versions of some queries.
What is the point of using ORACLE and not using all its non standard functions (analytics, pivots etc) ? ORACLE is a powerful tool.
Other DBs have there own strenght also, so why use the lowest common denominator just to be able to work on ALL of them? You will just lose in performance.
Just pick one DB, and use it fully with all its functionalities !
Pardon my ignorance here, but can't something like an ORM (object relational mapper) work for both SQL and Oracle?
I had similar requirements, to support both Sql Server and Oracle, and summarized my two years of experience with such problems in these articles:
Writing ANSI Standard SQL is not practical.
Think ANSI Standard SQL Is Fully Portable Between Databases? Think Again.