I want to use mysql proxy for processing queries trying to execute. I want to make this process available for all databases like mysql, ms sql server, oracle and ...
is it possible to use mysql proxy as base engine and connect these database from that? if no, is it possible to do this by making some little changes to mysql proxy source code?
You could use the standard external stored procedure support in the DBMS, but it would be difficult to map arbitrary queries to something meaningful.
Your are likely to be more successful implementing a lightweight parser as described in MySQL Client/Server Protocol and What communication protocol uses MySQL?.
Your preference that this can be done with 'some little changes' is likely not to be realistic. Expect a major job of the scale of ODBC to implement a generic SQL dialect translator.
I found that i have to use other exisiting proxies and change them in order to get what I need
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I have a scenario where I get queries on a webservice that need to be executed on a database.
The source for these queries is from a physical device so I cant really change the input to my queries.
I get the queries from the device in MSSQL. Earlier the backend was in SQL Server, so things were pretty straight forward. Queries would come in and get executed as is on the DB.
Now we have migrated to Postgres and we don't have to the option to modify the input data (SQL queries).
What I want to know is. Is there any library that will do this SQL Server/T-SQL translation for me so I can run the SQL Server queries through this and execute the resulting Postgres query on the database. I searched a lot but couldn't find much that would do this. (There are libraries that convert schema from one to another but what I need is to be able to translate SQL Server queries to Postgres on the fly)
I understand there are quite a bit of nuances that will be different between SQL and postgres so a translator will be needed in between. I am open to libraries in any language(that preferably runs on linux : ) ) or if you have any other suggestions on how to go about this would also be welcome.
Thanks!
If I were in your position I would have a look on upgrading your SQL Sever to 2019 ASAP (as of today, you can find on Twitter that the officially supported production ready version is available on request). Then have a look on the Polybase feature they (re)introduced in this version. In short words it allows you to connect your MSSQL instance to other data source (like Postgres) and query the data in as they would be "normal" SQL Server DB (via T-SQL) then in the background your queries will be transformed into the native pgsql and consumed from your real source.
There is not much resources on this product (as 2019 version) yet, but it seems to be one of the most powerful features coming with this release.
This is what BOL is saying about it (unfortunately, it mostly covers the old 2016 version).
There is an excellent, yet very short presentation by Bob Ward (
Principal Architect # Microsoft) he did during SQL Bits 2019 on this topic.
The only thing I can think of that might be worth trying is SQL::Translator. It's a set of Perl modules that have been around for ages but seem to be still maintained. Whether it does what you want will depend on how detailed those queries are.
The no-brainer solution is to keep a SQL Server Express in place and introduce Triggers that call out to the Postgres database.
If this is too heavy, you can look at creating a Tabular Data Stream (TDS is SQL Server network transport) gateway with limited functionality and map each possible incoming query with any parameters to a static Postgres query. This limits any testing to a finite, small, number of cases.
This way, there is no SQL Server, and you have more control than with the trigger option.
If your terminals have a limited dialect demand then this may be practical. Attempting a general translation is very likely to be worth more than the devices cost to replace (unless you have zillions already deployed).
There is an open implementation FreeTDS that you could use if you are happy with C or Java.
I have a vb.net project that uses a SQLite database. I do this by using dataset/table adapters. The client is happy and all works well. However I have just heard that they plan on providing this product to another customer that wishes to use their SQL Server database. So I am writing this post so I can mentally prepare for this before I begin. I am not a database pro and have really enjoyed the simplicity of setting up and managing an SQLite database.
So any ideas on the easiest way to support SQL Server as well? I am happy to run them parallel to each other. Can I just make a separate service / middleware that syncs the SQLite database to the SQL Server on a timer and does not care about what the main app is up to?
Any pointers are appreciated.
Synchronizing two databases is possible, if rather complex. You need some mechanism to find out which records have changed, and if it is possible to have new changes in both databases, you also have to resolve conflicts.
A timer-based approach doesn't sound efficient: in most cases, the timer doesn't have anything to do; and after some data change, there is some amount time where the databases are not synchronized.
Can't you just replace SQLite with MS SQL Server?
I.e., have some configuration settings that determines whether your program's data lies in SQLite or on a server?
Assuming that an SQL Server database with the required structure already exist, this would, in theory, need nothing more than a changed connection string, and supplying some user name/password (if the server isn't configured to automatically use Windows logins).
There shouldn't be any big differences in the SQL dialects used. You have, of course, to test all your queries.
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.
Is there any sort of non-SQL API for talking to SQL Server? I'm curious if there is a more direct way to retrieve table or view data.
(I don't have a problem with SQL, just curious if any of the layer between the SQL parser and the underlying data store is exposed.)
No, not as part of the actual SQL Server product, you'd have to install some other application to present/map the data in the manner you're after. But that would probably have to use SQL to get the data itself, defeating your intention.
Your best bet for retrieving data is SQL, but if you're interested in the plumbing you could look at TDS: http://en.wikipedia.org/wiki/Tabular_Data_Stream
You could look at the FreeTDS library: http://www.freetds.org/faq.html
Looks like the TSQLConnection only connects to existing databases, and I could not find another component that allows me to send commands to the database server.
I'm using Delphi 2009 with Firebird and MSSQL.
One idea that came was to connect to a system database (master or tempdb in MSSQL for example) and then send create commands to the server. This could be an option for MSSQL, but I'm not sure for Firebird.
I'm also aware of the new DBX metadata in Delphi 2009, but I couldn't find a way to create databases using it. All examples I've found is to modify existing databases.
Yes, you can. dbExpress now includes a powerful set of meta-data classes for doing just that.
Steve Shaughnessy gives a good introduction here.
Erick if you use Devart drivers you can connect without the databasename parameter and send the t-sql create database command.
dbExpress included in Delphi uses a "least common denominator" strategy. Information like query statistics which is available through native drivers is invisible with dbExpress. (Maybe I should ask a question like "Which feature in alternative dbExpress implementations made you switch?")
You can execute "CREATE DATABASE ..." on both databases with standard TSQLQuery.
Note that syntax differes between these two. Since dbx is lightweight lib, this SQL and DB specific action probbably will never be fully supported. It leaves you with SQL.
With Delphi 2007/2009 comes DBX4. You may use the low level structures there to create database programmatically. Look in dbxcommons.pas
You can send a "CREATE DATABASE" script through any connection (ADO, OLEDB, ODBC, etc) opened on any server (or even ms-access files) as long as it follows the specific server DDL syntax.