I'm writing a desktop application that uses the main access database that will be hosted on a central server, but there will be a laptop with the app on that has an offline mode so records can be created offsite. When the laptop returns I want it needs to be synced back to the main database.
Has anybody got any pointers on a way to do this, I've briefly read about JRO but is there an alternative / better method?
Originally, I was just going to write some custom code to do this, but thought I'd check to make sure there wasn't something already out there.
Jet Replication is a perfect solution for this kind of scenario, because you can use the simplest form of it, Direct Replication, and don't need to have any outside dependencies.
Assuming your server is named \HomeOffice\ and the database is named "MainDatabase.mdb" and is stored in the \AccessDatabases\ folder, you could use this code behind a command button to synchronize from the laptop to the server:
Dim dbServer as DAO.Database
Set dbServer = DBEngine.OpenDatabase("\\HomeOffice\AccessDatabases\MainDatabase.mdb")
dbServer.Synchronize CurrentDB.Name
dbServer.Close
Set dbServer = Nothing
Now, there's no error handling, and you haven't checked for conflicts, so you'd need to do more than that, but that would get you started with the basics.
See the Jet Replication Wiki for lots more information on Jet Replication.
Access (at least through 2003) has built in capabilities to replicate a database that would be far better to use than rolling your own.
Here's some documentation on that feature: Database Replication
MS Sync Framework could be the answer, but it's a bit tricky to set up... http://msdn.microsoft.com/en-us/sync/bb821992
There is the Microsoft Sync Framework that is compatible with ADO.NET and MS SQL Server / SQL Server Compact, but that's not a small component, more like a multi-component framework.
Related
I have been using MS Access databases via DAO for many years, but feel that I ought to embrace newer techniques.
My main application runs on end user PCs (no server) and uses a shared database that is created and updated on-the-fly. When the application is first run it detects the absence of a database and creates a new empty one.
Any local user running the application is allowed to add or update records in this shared database. We have a couple of other shared databases, that contain templates, regional information, etc., but these are not updated directly by the application.
Updates of the application are released from time to time and each new update checks the main database version and if necessary executes code to bring the database up to the latest specification. This may involve the creation or deletion of tables and/or columns. New copies of the template databases are also included as part of the update.
Our users are not required to be computer-literate and should not need to run any sort of database management software beyond those facilities provided by the application.
It all works very nicely with DAO/Access, but I'm struggling to find how to do it with SQL Express. The databases seem to be squirrelled away in locations that are user-specific and database creation and update seems at best awkward to do by program code alone.
I came across some references "Xcopy deployment" that looks like it could be promising, but there seem to be references to "user instances" that sound suspiciously like something that's not shared. I'd appreciate advice from anyone who has done it.
It sounds to me like you haven't fully absorbed the fundamental difference between the Access Database Engine (ACE/Jet) and SQL Server:
When your users launch your Access application it connects to the Access Database Engine that has been installed on their machine. Their copy of ACE/Jet opens the shared database file (.accdb or .mdb) in the network folder. The various instances of ACE/Jet work together to manage concurrent updates, record locking, and so on. This is sometimes called a "peer-to-peer" or "shared-file" database architecture.
With an application that uses a SQL Server back-end, the copies of your application on each user's machine connect over the network to the same instance of SQL Server (that's why it's called "SQL Server"), and that instance of SQL Server manipulates the database (which is stored on its local hard drive) on behalf of all of the clients. This is called "client-server" or "server-based" database architecture.
Note that for a multi-user database you do not install SQL Server on the client machines, you only install the SQL Server Client components (OleDb and ODBC drivers). SQL Server itself is only installed in one place: the machine that will act as the SQL... Server.
re: "database creation and update seems at best awkward to do by program code alone" -- Not at all, it's just "different". Once again, you pass all of your commands to the SQL Server and it takes care of creating the actual database files. For example, once you've connected to the SQL Server if you tell it to
CREATE DATABASE NewDatabase
it will create the database files (NewDatabase.mdf and NewDatabase_log.LDF) in whatever local folder it uses to store such things, which is usually something like
C:\Program Files\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS\MSSQL\DATA
on the server machine.
Note that your application never accesses those files directly. In fact it almost certainly cannot do so, and indeed your application does not even care where those files reside or what they are called. Your app simply talks to the SQL Server (e.g. ServerName\SQLEXPRESS) and the server takes care of the details.
Just to update on my progress. Inspired by suggestions here and this article on code project:
http://www.codeproject.com/Articles/63147/Handling-database-connections-more-easily,
I've created a wrapper for the ADO.NET methods that looks quite similar to the DAO stuff that I am familiar with.
I have a class that I can use just like a DAO Database. It wraps ADO methods like ExecuteReader, ExecuteNonQuery, etc. with overloads that can accept a SQL parameter. This allows me to directly replace DAO Recordsets with readers, OpenRecordset with ExecuteReader and Execute with ExecuteNonQuery.
Each method obtains and releases the connection from its parent class instance. These in turn open or close the underlying connection as required depending on the transaction state, if any. So a connection is held open for method calls that are part of a transaction, but closed immediately for a single call.
This has greatly simplified the migration of my program since much of the donkey work can be done by a simple "find and replace". The remaining issues are then relatively easy to find and sort out.
Thanks, once again to Gord and Maxwell for your advice.
This answer is too long to right down... but go to Microsoft page, there they explain how to make it: http://office.microsoft.com/en-us/access-help/move-access-data-to-a-sql-server-database-by-using-the-upsizing-wizard-HA010275537.aspx
I hope this help you!!
I am busy developing my own application, it uses a sql server database and it is connected through an entity framework. I use store procedures to insert, update, delete, select from my database.
The app works perfect on my machine even when I publish it. But my problem comes in when I try to install the app to my friend’s computer. It crashes and does not start because it cannot connect to the database.
Is there a way to publish my app with the database, without importing all the tables, store procedures and database into my friend’s pc? I just want to make it so the user just has to install the app and it works.
Your app relies on the db to work, so if you want to put it on your friends PC then you need to make the DB available somewhere, whether it be a local copy or a copy stored on a server somewhere running SQL.
How are you storing your connection string? Is it hard coded in the app or are you utilising the app.config file? To do what you're trying to do you'll need to put the connection string into the app.config file, so you can change it depending on the installation.
either that or
if you want to run your app without data, put a demo flag or something into the app.config file. Put some code into your app to check this value, if it's true then bypass the SQL code and maybe supply some demo data which is hard coded.
Does this make sense?
You could use SQL CE, but you may find it a little more difficult to 'design' your database in it if you are more used to working in SQL Server.
Have you considered SQL Server Express as an option?
On the connection string issue, you can now get the data connection wizard that Microsoft use in Visual Studio via Nuget; this makes adding a way to dynamically configure connection strings on your clients machine much easier.
Lastly, connection strings for the entity framework are different from standard SQL connection strings. Make sure that you clearly understand the differences before you start trying to configure them programmatically. Julie Lerman's excellent book on the Entity Framework explains the differences well.
Here's task: We have an sql server database. which is hosted at our server. What we need to do is: we need to create a non-techy-users interface (basically insert/edit forms) and let these non-techy-users to install this database locally, since they are located in the areas without internet connection. Then when they're done using the database we get the data from them and inster it in our database.
The biggest concern is that it is not trivial for non-it people to install sql server. Can you please advise me what solution should I choose? Simple Access should work fine, but i really do not want to mess with it and have data conversion back and forth between engines.
Sync Framework for SQL Server: your application uses a lite weight, embedded SQL Server CE (no installation, just a couple of DLLs deployed along with your app) and the sync framework manages the synchronization with the 'mother ship' SQL Server.
Out of interest, why do they need their own installation? Can't you create a new database on your existing instance?
If you're looking for an easy way to create insert/edit forms on your database, have you considered looking at Microsoft's new LightSwitch product (currently in Beta) or Microsoft's Dynamic Data?
I've been looking all over the web for a ColdFusion-based SQL administration tool for Microsoft Access and I can't find one that's simple, free and allows running SQL statements. Any suggestions?
Thanks for the recommends, guys, I'll try SQLSurfer. (MSSSME won't work for me.)
"DISCLAIMER: Using MS Access in a (web based) production environment is not recommended."
I understand that, and part of my timeline for this website is to migrate the database to MySQL on our server.
My primary interest in this is to be able to fool around with SQL commands LOCALLY so I can modify some tables. I wouldn't use this in a production environment anyway, especially not one that already has MySQL admin (Don't worry, I have plenty of backups in case I screw something up).
DISCLAIMER: Using MS Access in a (web based) production environment is not recommended.
That said, I have to admit that there are projects, customers, etc. where you can't get around having to deal with MS Access Databases the one or other way.
There is an Open Source project on RIAForge, called SQLSurfer which is a web-based ad-hoc query tool powered by ColdFusion. It is a simple way to execute SQL statements on your database (not restricted to MS Access). http://sqlsurfer.riaforge.org/ Actually there is no download link, but you can still get the code from SVN repo. http://svn.riaforge.org/sqlsurfer/
I have been working with an earlier version for a long time and I find it useful for executing prepared SQL statements. It is a very dangerous tool, especially in production, so I'd strictly recommend to include it in a password protected administration environment and deny public access.
Can RDS satisfy your needs? works with CFEclipse / CFBuilder.
Take a look at SQL Server Management Studio Express - though I've not used it with MS Access, so can't guarantee it'll work.
Hopefully someone more experienced with the two can come along and give more details.
You can easily make one your self.
On Adobe's website you can find at least 5 of those tutorials Here's one http://www.adobe.com/devnet/flex/articles/f4cf_firstapp_part1.html which uses Apache Derby, similar to MS Access.
Of course you need to think some things through, like authentication, making some field for writting SQL statement which is going to be sent as cfquery, but it should be a nice experience to make you'r own "phpMyAdmin" ;)
For MySQL there is CFMyAdmin.com. It might connect or could be adapted to tonnect to MS Access as well. I agree with Henry though, I'd set up the DSN for your access database, the RDS conection in CFBuilder and then use the query tool.
Other alternatives might be Lita (Mac based), or a FireFox add on like Sqlite Manager. They may surprise you as to what they can open.
Also, Charlie Arehart has a long list of CF based SQL Query tools. Maybe one of them could help: http://www.carehart.org/cf411/#query
Good luck
Is it possible to monitor what is happening to an Access MDB (ie. what SQL queries are being executed against it), in the same way as you would use SQL Profiler for the SQL Server?
I need logs of actual queries being called.
The answer depend on the technology used from the client which use MDB. There are different tracing settings which you can configure in HKEY_LOCAL_MACHINE\Software\Microsoft\Jet\4.0\Engines\ODBC http://office.microsoft.com/en-us/access/HP010321641033.aspx. If you use OLEDB to access MDB from SQL Server you can use DBCC TRACEON (see http://msdn.microsoft.com/en-us/library/ms187329.aspx). I can continue, but before all you should exactly define which interface you use to access MDB.
MDB is a file without any active components, so the tracing can makes not MDB itself, but the DB interface only.
UPDATED: Because use use DAO (Jet Engine) and OLE DB from VB I recommend you create JETSHOWPLAN regisry key with the "ON" value under HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\JET\4.0\Engines\Debug (Debug subkey you have to create). This key described for example in https://web.archive.org/web/1/http://articles.techrepublic%2ecom%2ecom/5100-10878_11-5064388.html, http://msdn.microsoft.com/en-us/library/aa188211%28office.10%29.aspx and corresponds to http://support.microsoft.com/kb/252883/en allow trace OLE DB queries. If this output will be not enough for you you can additionally use TraceSQLMode and TraceODBCAPI from HKEY_LOCAL_MACHINE\Software\Microsoft\Jet\4.0\Engines\ODBC. In my practice JETSHOWPLAN gives perfect information for me. See also SHOWPLAN commend.
UPDATED 2: For more recent version of Access (like Access 2007) use key like HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\12.0\Access Connectivity Engine\Engines. The tool ShowplanCapturer (see http://www.mosstools.de/index.php?option=com_content&view=article&id=54&Item%20%20id=57, to download http://www.mosstools.de/download/showplan_v9.zip also in english) can be also helpful for you.
If you're accessing it via ODBC, you can turn on ODBC logging. It will slow things down a lot, though. And it won't work for any other data interface.
Another thought is using Jet/ACE as a linked server in SQL Server, and then using SQL Profiler. But that's going to tell you the SQL that SQL Server processed, not what Jet/ACE processed. It may be sufficient for your purposes, but I don't think it would be a good diagnostic for Jet/ACE.
EDIT:
In a comment, the original poster has provided this rather crucial information:
The application I am trying to monitor
is compiled and at a customer's
premises. I am trying to monitor what
queries it is attempting against an
MDB. I cannot modify the application.
I am trying to do what SQL Profiler
would do for a SQL Server.
In that case, I think that you could do this:
rename the original MDB to something else.
use a SQL Server linked server to connect to the renamed MDB file.
create a new MDB with the name of the original MDB and link to the SQL Server with ODBC.
The result will be an MDB file that has the same tables in it as the original, but they are not local, but links to the SQL Server. In that case, all access will be going through the SQL Server and can be viewed with SQL Profiler.
I don't have a clue what this would do to performance, or if it would break any of the data retrieval in the original app. If that app uses table-type recordsets or SEEK, then, yes, it will break. But this is the only way I can see to get logging.
It shouldn't be surprising that there is no logging for Jet/ACE, given that there is no single server process managing access to the data store.
Keep in mind that the file sitting on your hard drive is simply a windows file. So, there is a big difference between a server based system and that of a simple text file, or Power Point file, or in this case a mdb file just sitting on the drive.
However you can get the jet engine to display its query optimizeing via showplan.
How to do this is explained here:
http://www.databasejournal.com/features/msaccess/article.php/3658041/Queries-On-Steroids--Part-IV.htm
The above article also shows how to access the jet disk read statistics, which I also find extremely useful for optimizing things.
Just remember to turn off that data engine logging system when you’re not using it as it creates huge log files…
you could write your own profiler, based on a "transaction" object that will centralize all instructions sent to the database, You'll end up somewhere with a "transaction.execute" method, and a transaction table in your access db. This table can then be used to collect transaction's instructions, start time, end time, user sending the instruction, etc.
I'd suggest upsizing the tables to SQL Server. There is a tool from the SQL Server group that is better than the Upsizing Wizard that is included with Access.
SQL Server Migration Assistant for Access (SSMA Access)
Also see my Random Thoughts on SQL Server Upsizing from Microsoft Access Tips page