Are there any free (gratis) providers for databases other MS SQL (e.g. MySQL or SQLite) that work with LINQ and support dynamic SQL query generation? E.g. table.Count() generates something like SELECT COUNT(*) FROM table and doesn't first load the whole table and then count the rows.
Here is the DBLinq project: http://code.google.com/p/dblinq2007/
DbLinq is THE LINQ provider that allows to use common databases with an API close to Linq to SQL. It currently supports (by order of appearance): MySQL, Oracle, PostgreSQL, SQLite, Ingres, Firebird
Whether these providers execute Count() in the way you describe depends on the quality of the provider, I suppose. Presumably some effort is made at optimization.
See also http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx
Check out ADO.NET Entity Framework. It supports MySQL via ADO.NET data providers and LINQ to Entities (similar to LINQ to SQL). Being a Microsoft tool, it has good Visual Studio integration and support.
Can you also explain why you want to support these databases?
NHibernate supports multiple databases and has a recently-released Linq provider.
Related
I'm trying to call a UDF using Entity Framework and I was wondering:
if I a use a different provider (LINQ to MySQL, LINQ to PostGreSQL) will it still work?
I've searched the SQL Standard and it's not freely available.
UDF implementations and rules are significially different in MySql, MS SQL and Postgresql. So really the first question is, can you migrate any UDF easily between this DBMSes? Generally, you cann't if you didn't created this UDF to be transferable from the very beginning.
After seeing this image:
http://2.bp.blogspot.com/_T-uXeKcGTnM/TIdoKBGwk9I/AAAAAAAABcs/CLW3_cRlN78/s1600/tumblr_kxovt0VLZy1qappj8.png
I wonder is exists any tool for translating SQL querys into MongoDB map/reduce query model??
Larger version of the image: http://rickosborne.org/download/SQL-to-MongoDB.pdf
Update to the question asked in Jan 2011:
A couple of sites exist now to convert sql to mongodb.
Convert MySQL Queries to MongoDB Syntax
http://www.querymongo.com/
And
Convert sql to mongodb
http://klaus.dk/sqltomongodb/
The simple anwser? No.
The slightly more complex anwser is some people have had luck translating more complex SQL to Mapreduce functions ...
http://rickosborne.org/blog/index.php/2010/02/08/playing-around-with-mongodb-and-mapreduce-functions/
http://rickosborne.org/blog/index.php/2010/02/19/yes-virginia-thats-automated-sql-to-mongodb-mapreduce/
However, that said ... generally speaking you might as well learn mapreduce properly because if the data is in MongoDB already ... you'll really need to know how to properly query MongoDB to get anything meaningful done!
MongoDB has wonderful and helpful docs http://www.mongodb.org/display/DOCS/Advanced+Queries
As well as an easy to use online tutorial: http://try.mongodb.org/
The simple answer: Yes. Hibernate OGM - JPA for NoSQL.
JPA is Java API for mapping objects to data stores.
It includes JPQL, a query language similar to SQL which adds the OOP concepts. It's not SQL, but you don't want pure SQL - that was designed for the relational paradigm.
Hibernate OGM proposes to simplify the programming model by embracing JPA/Hibernate APIs and semantics to store data in NoSQL stores like JBoss Enterprise Data Grid instead of the traditional RDBMS. (source)
Also see this Hibernate OGM: JPA for NoSQL talk by Hardy Ferentschik
Recently I happened to see this website mongoquery.com, you can try it.
You can use free sql to mongodb converter like: https://rapidapi.com/ariefsam/api/easy-sql-to-mongodb-aggregation/
Just to add to the last comment
re:The simple answer: Yes. Hibernate OGM - JPA for NoSQL.
JPA is Java API for mapping objects to data stores.
It includes JPQL, a query language similar to SQL which adds the OOP concepts. It's not SQL, but you don't want pure SQL - that was designed for the relational paradigm.
There is a company called UnityJDBC that has released a JDBC driver for Mongo that allows you to run SQL queries against mongo in any java application that supports JDBC.
you can download this driver free at
http://www.unityjdbc.com/mongojdbc/mongo_jdbc.php
hope this helps
You can also http://teiid.org which gives full range of SQL based access to MongoDB. You can use SQL through JDBC/ODBC or use REST/ODATA based access to MongoDB. Teiid uses MongoDB's aggregation framework to provide advanced SQL MongoDB query conversation.
After seeing this image:
http://2.bp.blogspot.com/_T-uXeKcGTnM/TIdoKBGwk9I/AAAAAAAABcs/CLW3_cRlN78/s1600/tumblr_kxovt0VLZy1qappj8.png
I wonder is exists any tool for translating SQL querys into MongoDB map/reduce query model??
Larger version of the image: http://rickosborne.org/download/SQL-to-MongoDB.pdf
Update to the question asked in Jan 2011:
A couple of sites exist now to convert sql to mongodb.
Convert MySQL Queries to MongoDB Syntax
http://www.querymongo.com/
And
Convert sql to mongodb
http://klaus.dk/sqltomongodb/
The simple anwser? No.
The slightly more complex anwser is some people have had luck translating more complex SQL to Mapreduce functions ...
http://rickosborne.org/blog/index.php/2010/02/08/playing-around-with-mongodb-and-mapreduce-functions/
http://rickosborne.org/blog/index.php/2010/02/19/yes-virginia-thats-automated-sql-to-mongodb-mapreduce/
However, that said ... generally speaking you might as well learn mapreduce properly because if the data is in MongoDB already ... you'll really need to know how to properly query MongoDB to get anything meaningful done!
MongoDB has wonderful and helpful docs http://www.mongodb.org/display/DOCS/Advanced+Queries
As well as an easy to use online tutorial: http://try.mongodb.org/
The simple answer: Yes. Hibernate OGM - JPA for NoSQL.
JPA is Java API for mapping objects to data stores.
It includes JPQL, a query language similar to SQL which adds the OOP concepts. It's not SQL, but you don't want pure SQL - that was designed for the relational paradigm.
Hibernate OGM proposes to simplify the programming model by embracing JPA/Hibernate APIs and semantics to store data in NoSQL stores like JBoss Enterprise Data Grid instead of the traditional RDBMS. (source)
Also see this Hibernate OGM: JPA for NoSQL talk by Hardy Ferentschik
Recently I happened to see this website mongoquery.com, you can try it.
You can use free sql to mongodb converter like: https://rapidapi.com/ariefsam/api/easy-sql-to-mongodb-aggregation/
Just to add to the last comment
re:The simple answer: Yes. Hibernate OGM - JPA for NoSQL.
JPA is Java API for mapping objects to data stores.
It includes JPQL, a query language similar to SQL which adds the OOP concepts. It's not SQL, but you don't want pure SQL - that was designed for the relational paradigm.
There is a company called UnityJDBC that has released a JDBC driver for Mongo that allows you to run SQL queries against mongo in any java application that supports JDBC.
you can download this driver free at
http://www.unityjdbc.com/mongojdbc/mongo_jdbc.php
hope this helps
You can also http://teiid.org which gives full range of SQL based access to MongoDB. You can use SQL through JDBC/ODBC or use REST/ODATA based access to MongoDB. Teiid uses MongoDB's aggregation framework to provide advanced SQL MongoDB query conversation.
I am working on an application that will need to communicate with many different applications running on different database platforms. I will know the table schema before runtime but I won't know the database platform (MS SQL 200X, Oracle 9i, 10g, etc, MySQL 4.0.1, 5.x, etc, sybase, etc) until runtime.
It's my understanding that each of these systems have a slightly different dialect. Do I need to use nhibernate to handle the differences when connecting to these systems or can I use ADO.NET and pass raw SQL strings (select * from table)?
If you only need to use ANSI SQL statements, which should be implemented by all of the databases then yes, you can just use ADO.NET.
In my experience the main problem with database-agnostic code is the use of surrogate keys, like sequences or autonumber fields, as all databases implement these differently.
If you do need to use features that differ across databases then I don't think that it is reason enough to go to an object relational mapper like NHibernate - only do that if you have other reasons to do so. You can implement your own handling of syntax differences by generating different SQL for different databases easily enough.
SQL should be standardized for all dbs but they don't all use the same syntax so it really depends on what SQL you're calling. For example, SQL Server uses TOP while Oracle uses rownum. Even if they're all DDL, some syntactically differences between DBMSes can be an issue.
If select * from table is all you want, then there shouldn't be a problem, other than performance hits.
I'm currently working on a project for a web application that may be installed on several different servers with various software configurations. I want to make my application as flexible as possible by allowing the user to have various SQL servers installed. The problem is the SQL syntax used by any two server vendors does not match up. For a simple example, here is the same SELECT statement for MS SQL and MySQL:
MS SQL - SELECT TOP 1 * FROM MyTable ORDER BY DateCreated DESC
MySQL - SELECT * FROM MyTable ORDER BY DateCreated DESC LIMIT 1
Are there any standard way to abstract the statement creation for various vendors? Any online resources or books discussing this problem? Any hints or smart-alec remarks that I'd find useful?
Further information: I'm writing my we application in vanilla ASP running on a Windows server.
Thanks, Spara
You can conform to ANSI SQL 92. All major RDBMS I know will support that.
However, there are tons of things individual RDBMS makers have added to enhance their own flavor of SQL. That is where you get into a lurch.
You may have to branch out in code depending on the RDBMS you are connecting to and generate / choose the appropriate SQL statement at that point.
A better option would be to create a DAL for each supported RDBMS. Implement a DAL interface across the DALs to make them uniform. This should be easier than switching in code.
I suggest that instead of trying to please everybody, you should write your code such that you support the top one or two systems that you expect to deploy on, and add support for other RDBMS as and when required.
I suggest you use an ORM (linq, nhibernate etc) to abstract the SQL dialect away rather than trying to write plain vanilla SQL.
Edit: Is there an OR/M for Classic ASP?
You know, I bet you could get by with strictly ansi sql, it will just take some effort and probably extra work. i.e.
SELECT MAX(*) FROM mytable ORDER BY datecreated DESC;
There will be workarounds in ansi because really all of the db specific constructs are ways to shorten and or shortcut existing ways of getting at or describing data. Another option might be to restrict access to the various databases to stored procs and user-defined functions. That way, you could write scripts for a bunch of the dbs you know will be used with the requirement that your db specific script be run before the app will work.
Just an idea.