My compiled VB.NET program is stored on Windows Server 2016. This program will call a database (.mdb) which is also located on server.
I have created user account with password clients (user) to access and run this program through share folder.
My problem is, this program only can be run by only one user at a time due to database lock for current user. There is any way to make it so that this program can be run by multiple users at the same time?
I never heared of Windows Server 2017. Perhaps you mean Sql Server 2017?
You should/could use a database like SQL Server, Mysql or Postgresql instead of Microsoft Access making multiple user much easier.
See Is there a downside to using Access as a database? for a bit more information.
Related
I'm working on a database driven program in Visual Studio 2015, in C#, Windows Form Application, and I'm using SQL Server 2014 for my databases, downloaded the most recent version from the MSDN site.
I've got it working well. But if I want other users on other computers and different versions of Windows, this would require them to have SQL Server installed, correct?
Basically the app is used for storing current medications, moods, a mood quiz, symptoms, etc.. and I store all the results in SQL Server databases. They can be edited, deleted, etc through the program's GUI. Do the users need SQL Server installed to use this app?
If so, is there an alternative to keeping databases without having to have the SQL Server connections, or is there a way to do this without the users having to have SQL Server installed? I don't want remote connections to me, I want it standalone.
Does this make any sense? If not, I can explain more. I know way back in the days of Visual Basic 4 I was making, reading and writing databases without SQL. But that was 16 years ago. So I'm wondering what the easiest solution to this is. Thanks!
In other words, you want a database that you can a) distribute to end users freely and b) that will 'connect' just to the copy of the database they have stored locally.
Here are a few options ---
SQLite over ODBC is as-easy-to-use as MSSQL, the driver can be found here:
SQLite ODBC
Use ConfigurationManager.OpenExeConfiguration to read / write your app config .xml file and use it as a key / value store. I can provide examples if needed.
Dynamically create an Access database, it should work as well as MSSQL for most things, with less overhead. Here's how:
Create an Access Database
Use SQLIte DLL. Details on SO
create-sqlite-database-and-table
I am not very familiar with Access database till now i was only programming to SQL Server but now it's time to do so. I am building WinForms application which will be using Access database and i have some question related to that point if you don't mind. My application will be used by multiple users and there will be one access databsae. My questions as below:
Is there any problem with accessing access database in same time by many users or only one user can be connected?
If i develop my program to use access 2016 and some of my users will have diffrent windows version and also diffrent access version
will it works?
Should i know something else? :)
If your client want to have a file based database and this is a project constraint , MS Access is the best choice. If you want a more detailed advice, please let me know how many users will perform Read/Write or Read transactions, the size of the database and if the application will run in client-server mode in a LAN/WAN, Cloud or Remote Desktop environment.
Back to your questions:
Depending on these conditions you may range from 10 to 20/25 users. Remember that you can always try with MS Access and later upgrade to a MS SQL database in a couple of hours.
If your front-end application can link to a 2016 Access database, it will do that without installing MS Access to the clients that will run your App, i.e. the vb.net compiled App will install all needed drivers. If you develop your App within MS Access 2016 (Access Form and reports, some VBA) you can run it with the free runtime version of MS Access, but this only when no older version of Access is installed on the running workstation.
Please check with your client the real reasons for a file-based database...
To answer the questions as asked:
You might run into an issue with this, as access was really designed as a personal use database. Having anything more than a small handful of users hitting against it at once will in fact cause problems, as it's not really well designed for that purpose...
This should in theory be fine, as the application itself is interfacing with the database, not the end user...
It seems like you're taking a step backwards using access for this, and SQL might very well be better suited for this purpose. This isn't me trying to just bash access either, this comes from personal experience. Going with this sort of design is likely to cause you more headaches than good.
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 have been working in VB6 to VB.NET migration project.In VB6 project they have individual databases(access db .mdb) for every user now we made that to Centralized database SQL SERVER.In VB6 the individual db is a replica DB and has a Master-db which located some where. Now we need to do this process for SQL SERVER also.How can we achieve this for Centralized database like SQL Server?This should work for each and every user also.
Can anybody help regarding this or share any links ?
SQL Database is used as a single .mdf file (.log file is also with it so 2 files)
So the simple concept for one user per one file is not suitable (however it can be
implemented i.e. each user will have its SQL database working separately on his computer)
You will then implement the logic to update the main database placed at some server
on detecting the idle time of the machine or some other suitable time
you can also use
I've started working on my database desktop application. The goal is to have one centralized database, so that each employee could connect.
My goals:
Centralized database on SQL Server 2008 Express
Use Sql to Linq
First run of application should create structure of database on server.
Now my question: how to do the last point?
I know that I can generate sql script via SQL Managment Studio and then execute it, but maybe there is some better way?
Like the comments said, I'm not sure why you would want to do this, but if you have one centralized database machine and you want to create a new database per user upon the first connection, then you could create one canonical/template database and the clone it via scripting on the first connect.
Your UI would say something like "Please wait while we create your new database..." and you'd run CREATE scripts for the database/tables/stored procedures/views/etc.
Just remember it might be a major pain to update the schemas of these databases once the cat is out of the bag.