I have an old compiled Access Application mde file. This application has linked tables to network shared folder. I tried to upgrade main database using upsizing wizard on main database and everything went well. Then when the application starts it gives error message that
Microsoft jet database engine cannot find the input table or query table
I have checked the shared mdb file it has exact table names and everything.
Then I called the guy who developed this application. He said I have to rewrite the application to not use Jet engine...
What does Jet Engine has to do with linking tables? Do I really have to rewrite the whole application to use ADO?
Many questions:
do you have the source MDB file? I can't recall if creating an MDE fails if the linked tables are not correctly connected. In any event, should you end up needing to alter the app, you're going to need the source MDB file.
the error message you report should give the name of the missing table.
do you know when the error is being reported? There could be any number of places where simply replacing tables linked to a Jet MDB back end with ODBC links to a server will not fix things. For instance, should there be any saved queries or SQL in code that bypasses linked tables and uses a direct connection string, that could produce an error like you see.
in regard to the developer's response that "I have to rewrite the application to not use Jet engine..." either you misunderstood what he said, or your developer is completely incompetent. Or both, I guess. Jet works very well with ODBC linked tables and if you're using an MDB front end, it is impossible to completely eliminate Jet, as the MDB is a Jet data file. The desire to eliminate Jet mostly comes from people who can't be bothered to learn how to use it properly.
It sounds to me as though you're getting an unhandled errror but insufficient information on what's producing it. You need the actual MDB to troubleshoot it, as the code isn't there to display in the MDE so there's no way to figure out what the actual source of the problem is. If your developer won't give you the MDB, then you need to check the contract under which the app was developed -- if you agreed to letting him control the source code, you're basically at his mercy and should fire whoever signed off on that. For what it's worth, when I deliver an MDE to a client, they also get the full MDB. They generally don't do anything with it, but should I no longer be available to do further development work, they've got the source code that they can give to whomever they want.
Last of all, I think it's very unlikely that even if you get your app working, a mere upsizing is going to offer much in terms of performance or stability. It is true that very often, 90% or more of an upsized app will work without alteration, but the other 10% can be very problematic. Often you need to move certain operations server-side to get the efficiency a server back end offers. This means your front end app needs to be re-architected to work better with your upsized back end. The degree to which this is true will differ from app to app, but it's very seldom that absolutely everything works without revision.
You did change Access database version?
It is possible that your mdb was linked with old version of Jet drivers and these drivers cannot connect to newer mdb version.
Related
I am using the Project Server application which sits on top of a database. I have hundreds of edits to make to Project Server but It’s unrealistic to edit all of the Projects, one at a time. Instead of doing it one at a time, I was thinking of running an UPDATE sql script to write directly to the database.
Is this considered bad practice and would it break project server?
As soon as you do any writing on the DB by yourself or touch the schema you just lost your support from microsoft. They reserve the right to do any change in the db with each update.
Do not do it. Don't.
Use PSI or the REST API. Those are your friends.
I'm trying to connect to a database supplied by a vendor. I have read-only access.
Every tool I use (SQLWorkbench, DBeaver, etc...) refuses to connect using the jconn4 drivers with an error message along the lines of:
Metadata accessor information was not found on this database. Please install the required tables as mentioned in the jConnect documentation.
Normally the fix is easy. Run:
ALTER DATABASE Upgrade JCONNECT ON
Unfortunately in this instance, I only have read-only access and the vendor refuses to turn it on. Apparently with good reason. I took a snapshot of the Windows server, then did a few tricks in the background to get access to the database with read/write privileges and ran the command. Then I restarted the database server. Every client that uses the database started crashing and throwing bizarre errors. I rolled back to the backup and called the vendor and played dumb. They immediately knew the issue and said "somehow someone turned on metadata accessor tables--good thing you had a backup" and that was the end of it.
Is it possible to access the database without turning on those tables? Are they specifically related to using jconn4 for connecting? Is there another way to connect? (I don't pretend to understand anything about the jconn4 library or Sybase--I rabidly dislike both things). Ideally I would love to be able to browse tables and key relationships with a GUI, but I'd settle for just being able to execute SQL commands and get results while testing.
I have a series of Access 2002 "Front-end/Back-end" applications all related to each other. For example, application A has linked tables with application B and vice versa.
The applications are at a stage where daily compaction and repair is required due to the volume and high level of corruption. Moreover, to be able to make the applications work properly, I must make the changes in a virtual environment with Access 2002. I also need to reinstall "Access runtime 2010 - 32bits" and copy the Access files (.mde) on every workstation (Windows 10) every time I am making a change in the applications.
#Gustav This is a temporary option (6 months to 18 months) because the customer would like to go to a complete solution with SQL database. The studied solution is configurable and already has a SQL database schema.
I have already done the test to transfer forms, tables, queries and modules to Access 365 but I have errors in the VBA code. All business rules are coded in the VBA code. I also did the transfer of the tables to SQL Server 2017 but I'm afraid I will have to change a lot of VBA code because of the disuse of the DAO engine in the Access 365 front-end.
In fact, to be clearer, I wonder about the need to change the front end to Access knowing that it is a temporary solution.
Maybe, I should keep the software under respirator by eliminating data history in large tables. The time the client takes their decision. Find the "sweet spot" that would allow me to erase and continue to maintain it without having to worry about corruptions because I have a hard time seeing a substantial gain in the migration to the Access 365 front-end. What do you think?
I have already proposed to migrate applications and tables in the new version of to Access 2019 and even moving on SQL Server. However, for now, I must put the application on the respirator and continue the daily compaction until a decision is made.
I would like to know if there is a gain to migrate from Access 2002 to the Access 2019 version knowing the total limit of 2 GB Access. What are the major constraints he would have to migrate to a SQL database knowing that the VBA application and code uses the DAO method?
#Albert D. Kallal
I really like your answer. I should come to a decision soon.
However, I have 2 additional questions. Perhaps, could you guide me on the subject.
There are two things that have recently came to haunt the tranquility that reigned over these applications.
1- For a unknown reason, one of the applications that was part of the swarm of Access applications was blocked for some time with these errors 'Runtime 3027: Cannot update: Database or object is read only'. The problem is that some users have ignored this error and continue their tasks which caused a data shift.
I had to go back with backup copy because some tables were not updated.
Looking more closely at the error in the VBA code I noticed that it all came from the DAO Recordset.Edit method containing queries with multiples joins.
I managed to work around this problem by modifying the Edit method with DoCmd.RunSQL and by changing the query from a Select to an Update query.
However, the whole method worked perfectly well before.
Can you explain to me the cause of this error?
2- The original developer did not necessarily use best practices for the design of the application (no autonumber, some tables without primary key, no foreign keys) so I'm afraid that a new design will need to be done if I migrate to a SQL Server database. Or maybe to save time, as this solution is going to disappear in 18 months, I should only replicate the bad practices in SQL Server and pray that it does not cause any more glitches. What would be your professional approach?
Thank you
There may be none. Open the database in Access 2019/365 and save it in the 2007 (accdb) format, and check it out.
As for the distribution, you can make this fully automatic using a script and a shortcut. It is explained in full in my article:
Deploy and update a Microsoft Access application with one click
If you don't have an account, browse to the link: Read the full article.
Push hard to get a confirmation on the move of all the shared tables to an SQL Server backend.
A few things:
To update your mde or accDE front end? That is a simple copy to each workstation. You don’t need to re-install the runtime each time. There is no “special” connection between one particular application (mde/accde) that you deploy to each workstation.
In other words:
If you writing software in VB6, then you need to install the VB6 run time (but only one time). After that you can simply copy + deploy your application to each workstation.
If you writing software in say .net then again, you have to ensure the correct .net framework is installed on each computer. Once done, then again you can update your software by a simple copy to each workstation.
And the same goes for using the access run time. Once installed, then you can simply copy any mde/accDE to that workstation, double click on it and it will run. So the run time is not connected to any particular database you copy to the workstation. Once you have the runtime installed, then you can rather easy cook up some automatic update code for the front end to "check" some version number, and then copy down the new updated front end. There are quite a few ways to do this - even a simple batch file can often suffice here.
So in near all cases these days, you will have to do “one time” install of the required run-time and support libraries. This is the case for .net, older VB6 programs, or Access.
As for migration of the access table data to SQL server?
You should be able to simply migrate the table data to SQL server. Now link the application tables from the older access back end to SQL server.
At this point, 99% of your VBA and even DAO recordset code should work just fine.
There is no need (or even a good reason) to dump using DAO code you have – it should work as before with VERY few modifications.
About the only change is for code that does this:
Dim strSQL As String
Dim rst As DAO.Recordset
strSQL = "select * from tblCustomers where City = 'Edmonton'"
Set rst = CurrentDb.OpenRecordset(strSQL)
' above for SQL server becomes:
Set rst = CurrentDb.OpenRecordset(strSQL, dbOpenDynaset, dbSeeChanges)
And you can even migrate the tables with indexes, and table relationships intact by using the Sql Server Migration Assistant for Access (SSMA). You can find this fantastic tool here:
https://www.microsoft.com/en-us/download/details.aspx?id=54255
So, about 99% of existing forms and VBA code will work as before after you migrate the data to SQL server.
I've a project that uses EF4 on the client side to talk to a SQL Server db. On that DB there's a bunch of SPs that do operations on records and return subsets of records. Nothing particularly major, about the most intensive bit is generating a few bytes of random data and overwriting part of a byte array with it. The records have to stay on the server for security reasons because the data array's akin to a private key.
In the past I've used ADO for DB access within the SPs, but that seems horribly outdated and clunky compared with EF4. And now that I've updated to SQL Server 2012 which has .NET4 available for SQLCLR stuff, I'd like to do the next SP using EF4 and shift to using that in the future.
Problem is, nobody seems to do it yet and I'm not sure it's possible yet.
I know I could do this by writing a seperate server-side app and having that talk to the the DB on my behalf, but that means the client side needs a connection both to the database and to the helper service. More things to get working, more things to go wrong, and aesthetically displeasing.
I've created a simple assembly that uses EF4 to give access to a couple of standard tables. No extra references added. On importing that into SQL Server, I get errors that it can't find "System.Data.Entity" and "System.Runtime.Serialization". Ok, I copy them into the same directory and import again. I get a couple of warnings that I'm in uncharted territory, which is fine for experimenting. But then I get a missing assembly "smdiagnostics". And I can't find any file on the drive that has "smdiagnostics" in the name, a full text search through the project for that term gives no hits, and I've not found much elsewhere that's helped me track down where this can be found.
So does anyone know how I can either satisfy or remove the requirement for smdiagnostics?
Ah. Bit of a "doh". Copying individual assemblies into the same directory as my own DLL isn't the way to go, just a knee jerk reaction to seeing an error message about the referenced assembles not being found even after looking in the same directory.
Assuming the use of the 32 bit server, having selected your own db and having already set trustworthy on, this registers everything needed in order to add an EF4 project;
CREATE ASSEMBLY [System.Data.Entity]
from 'C:\Windows\Microsoft.NET\Framework\v4.0.30319\System.Data.Entity.dll'
with permission_set = UNSAFE;
My customer is a dental practice that has bought a piece of practice management software. This software was installed on their local server, including a patient database, a schedule and all manner of medical records. Now they want me to write some utilities for them that aren't provided with their package, and for this I need the ability to query this database.
I tried calling tech support of the software manufacturers (Patterson/EagleSoft), and it's difficult finding anyone who understands the technology enough to answer my questions. As far as I can tell, there's no API for their software, and understandably they're reluctant to tell me how to query the DB directly, programmatically. They do have an interactive query window, but obviously that's no good for writing automated queries. All that they would let on is that somewhere there's a SQL Server DB, but the ODBC drivers to connect to it are SQL Anywhere drivers (huh?).
So I searched around on the server and couldn't find any database files. Then I discovered that the installation creates some kind of proprietary virtual machine, which is only visible to the EagleSoft software. But while they've been very good at insulating their DB in layers of obfuscation, they have left open an ODBC driver, which is indeed an SQL Anywhere connection.
Now after that fascinating and lengthy preamble, here is my question: What queries can I run over this ODBC connection to interrogate the DB as to its structure? If it's a SQL Server DB underneath I could use the sysobjects table, but I don't fully grasp how you can use a SQL Anywhere ODBC connection to connect to a MSSQL DB. And If they were misinforming me and it really is a SQL Anywhere DB underneath, what are the queries to run to get at the DB structure?
And if there's anyone else out there who's ever succeeded in actually querying EagleSoft (or any similar proprietary package) - please tell me how you did it!
Turns out the simplest way to do it was to write a little app using OdbcDbConnection, and connect using the DSN installed with the software. It took one probing 'select * from sysobjects' to reveal that it is, indeed a MS-SQL database underneath all that, and I'm good to go from there!
I'd use a tool like squirel which is great at browsing any database to check if anyone was successful with "SQL Anywhere" this google result:
http://blog.gmane.org/gmane.comp.db.squirrel-sql.users/month=20091001
Shows that others have managed to get squirrel to do this. It's quite easy to use... assuming of course you manage to get the connection working!
A few tools that might help are SQLWorkbench and Django. I use SQLWorkbench to copy the data from the production system into a Postgres database so I can hack on it without damaging the production environment. Then I use Django's inspectdb to generate models of the database environment. From there it's easy to create 'views' into the database and templates to display exactly what I want.
UPDATE: As of Eaglesoft 19, it looks like Patterson has password protected the database and they have gone out of their way to prevent users from getting at the data without paying them for access.
UPDATE: Like I mentioned before, Eaglesoft 19 has a locked-down version of the database. For read-only access you can call Patterson and ask them for the password to the "Database Admin" section of their "Technical Reference" tool that is installed on your server. Once you are in there, there's an option to set a read-only password for access to the database. The username is 'dba' and whatever password you set. Some times it takes a bit of back-and-forth with them to give you access, but my solution was to say "We've been putting patient data into Eaglesoft for over a decade and we've always had access to the database. Now you're restricting it and telling us we have to pay for access. It sounds like you are trying to extort money by holding our data hostage. I should probably run this by our legal team."
EDIT: Nov 18 2022: You can still easily get read-only access to an Eaglesoft database in 21.20.08 (the latest version) by calling Patterson and getting the "day password" for Technical Reference. From there you can enable a read-only user. Based on some of the changes Patterson is making to their application architecture and the database, I suspect they will stop using direct connections to the database in the next year or two. When they make that change, you will only be able to access the database through their API Server. After playing "phone tag" with one of their salesbros for several weeks and doing some light social engineering, I managed to get their price list for going through the API server. It's atrocious. Most offices pay ~$500/mo to Patterson for free tech support and free upgrades. They want developers to pay nearly as much per office for access to the API. They've realized they can lock practices out of their own data and monetize it. We are working with a company that is actively developing a replacement for Eaglesoft to get away from this horrible vendor lock-in.
I have written my own PHP driven website to access and manipulate data in my eaglesoft database. You simply create odbc connection to local DNS entry and done. To see database structure you can use the technical reference included in eaglesoft or advanced query tool.