I have a legacy Access 97 Frontend application which utilises a SQL Server 2005 backend over a SQL Server ODBC Driver (Connection), we use the Linked Table feature on this setup.
I create, amend and link in tables on a daily basis and I am aware of the conversions that occur between the different data types.
There seems to be an issue with one table that I recently created, it has exactly the same setup and permissions as many of the other tables in the database but once I link it into Access 97 it seems to show #NAME in all columns and I also receive an 'ODBC Call Failed' error.
If I remove the Primary Key from the table and do not select a 'Unique Record Identifier' then I am able to view the data in the table but I obviously can't edit it.
There are 3 columns which are VARCHAR's and are over 255, if I reduce these columns to 255 or less I am then able to view the data in the table but if I then try to edit or delete the data I receive a new error 'The Microsoft Jet Database engine stopped the process because you and another user are attempting to change the same data at the same time' - I know this is not possible because at present I am the only one with access to the table.
In this particular table there are 146 columns, if I delete half of these then the table starts to work as it should, again I have tables that have far more columns than this and work perfectly.
Troubleshooting issues like this can be frustrating for sure.
I have found this article very helpful for my linked tables:
Optimizing Microsoft Office Access Applications Linked to SQL Server
Specifically read the section titled Supporting Concurrency Checks.
One thing you might try is adding a "timestamp" column to the table in question.
Related
A new issue has cropped up this morning. I have databases that reside on SQL Server and I use Access for the front end. One of the databases which has been in use for at least 10 years now suddenly stopped working today, and I have found that the issue is one that is affecting 2 (possible more, I've not checked them all) tables.
When I open the table in access all I get is #DELETED in all the rows and colums. I have seen this behaviour before and it is usually something to do with the data type but this doesn't seem to be the case in this instance.
To troubleshoot the problem I have created a view that retrieves all the columns from the table and when this view is linked and opened in Access I have the same issue. I have found that if I link to the view without selecting a unique record identifier I can see the data without any problem. I could use this as a work-around, but clearly it is not ideal.
The SQL server version is 14.0.2037.2 and I am accessing it using SQL Server Native Client 11.0.
I have found the cause and solution. The affected tables had nvarchar fields as the primary keys. SQL Server Native Client has been deprecated for some time now and is replaced by MS OLE driver which is our mistake. The reason this problem has only reared its head now is due to an update to MS Access 365. I found this which has more details:
#DELETED when linked with ODBC
I had the same issue. This situation emerged this past weekend (5/29/2022).
This is a bug created by a 365 Office update. My update occurred 5/29/2022. The best remedy is to roll back your most-recent 365 update.
In my application, the #Deleted value appeared in all cells linked to any SQL Server table having a nvarchar field included in any unique index - it didn’t have to be a primary key. In my case, eliminating the unique attribute in any index including a nvarchar caused the problem to go away.
A new issue has cropped up this morning. I have databases that reside on SQL Server and I use Access for the front end. One of the databases which has been in use for at least 10 years now suddenly stopped working today, and I have found that the issue is one that is affecting 2 (possible more, I've not checked them all) tables.
When I open the table in access all I get is #DELETED in all the rows and colums. I have seen this behaviour before and it is usually something to do with the data type but this doesn't seem to be the case in this instance.
To troubleshoot the problem I have created a view that retrieves all the columns from the table and when this view is linked and opened in Access I have the same issue. I have found that if I link to the view without selecting a unique record identifier I can see the data without any problem. I could use this as a work-around, but clearly it is not ideal.
The SQL server version is 14.0.2037.2 and I am accessing it using SQL Server Native Client 11.0.
I have found the cause and solution. The affected tables had nvarchar fields as the primary keys. SQL Server Native Client has been deprecated for some time now and is replaced by MS OLE driver which is our mistake. The reason this problem has only reared its head now is due to an update to MS Access 365. I found this which has more details:
#DELETED when linked with ODBC
I had the same issue. This situation emerged this past weekend (5/29/2022).
This is a bug created by a 365 Office update. My update occurred 5/29/2022. The best remedy is to roll back your most-recent 365 update.
In my application, the #Deleted value appeared in all cells linked to any SQL Server table having a nvarchar field included in any unique index - it didn’t have to be a primary key. In my case, eliminating the unique attribute in any index including a nvarchar caused the problem to go away.
Desired result and why:
I have a lot of old Access databases that we are trying to get to SQL Server, and I'm essentially trying to make the Access DB the "middleman" so our old programs can still read/write to them but the information will also be saved in SQL Server. We need the middleman because of how interconnected these tables are through various programs we are rewriting in modern languages. Once we rewrite all of them we will cut the cord and live in SQL Server, but this will take a lot of time.
What I've tried:
We tried creating a linked table to SQL Server and renaming it so it would take the place of the original table. After doing this the table stopped receiving data so we quickly reverted back.
In order to investigate this I created Table B which is just another linked table to SQL Server, and then tried using the After Insert macro on Table A to send any new rows to the linked table but nothing happens. If I manually add a record to Table B it carries over to SQL Server just fine, but I can't get Table A to send data to Table B. I created Table C that is just a local access table and if I manually add a record to Table A it does show up in Table C. No errors at all, it just doesn't do what I need it to do.
I'm lost on how to accomplish this and open to any help or suggestions on how to move forward with this. One thing to note though, is that most of the access databases I have are not using forms at all which is I'm trying to take the macro route instead of any VBA. I need these to trigger without any interaction from the user.
You should use the tool dedicated to this task:
SQL Server Migration Assistant for Access (AccessToSQL)
Ok, there are from comments some new and signficant moving parts here.
For example, data is to be migrated to sql server. As noted, EVEN in access land, all and every table needs and should have a PK for the "basic" data base operations. While it is possible to do some work, and say some importing of data, the instant one wants some forms, VBA code and starts to build a working applcation? Then all tables should have a PK.
And of course if you moved the data to sql server, then it not going to make a lot of sense to have OTHER applcations attempt to modify the linked tables in access, since the data is not in Access anymore!!! Those other sources in theory should thus also hit sql server, and not attempt to use what amounts to a link on a linked table.
However, it does depend. For example, if you use vb.net code and say open a access database, you CAN in fact have that vb.net code open a access table, and in fact it can be a linked table. (however, it would make a WHOLE lot more sense for the vb.net code to open and hit sql server - introduction of a link on a link is going to be problematic.
However, in testing, I have found that say vb.net can open a access table, and even if it is a link, then access will translate though the jet engine (the access data engine), and you can do this.
However, data macros and table triggers on existing access tables? They might work on linked tables, but you of course need to ensure that the linked table does allow edits, and allows inserts. Only AFTER one has verified that you can click on a linked table to sql server - can edit, and then add should one mess around with data macros and triggers on say local tables.
it also depends on what the new software tools and platform is being used here.
But, from a basic database point of view - and general data mangement?
All code, and designs should assume, and be designed around the assumption that each row of data has a PK. This is not always possible, but is a RARE use case.
Practical data management - and use of a database should from both table designs, and from workflow designs, and from a developer point of view assume the concept of a PK row id. Without such assumptions, then you not in the software industry anymore - but in a hack field, and one that will result in great future difficulty when attempting to build work flows and build general information systems.
So, with above in mind: Your table B - it has to work as a valid sql server table.
The sql server table(s). They need a PK, and after linking to sql server, you can open up the linked table in access. Test if edits work, test if adding works, and even perhaps test if delete works. Only AFTER such time, do you now want to start testing any code or other operations from the Access client side.
Introduction of using a linked table from another application? That is a foggy area, but I can confirm for example that say .net oleDB provider will and can open a access database and use + consume even linked tables.
You also don't mention if you using sql logon, or windows auth for the sql server linked tables. But if you using sql logons, then when linking a table, you see this check box - and you want to ensure you selected this when linking the table(s) in question:
Note that you ONLY get this prompt on the first time create of the table link - additional use of the linked table manager (such as re-fresh links) does not offer this prompt. If you don't select the save password option, then you often see a sql logon prompt when you attempt to open a linked table in access.
I have 2 link tables in a MS Access database. One of the link tables links to a table in a Sybase database and the other links to a SQL Server database.
The tables structures are same and has the same data too, barring a few rows.
I tried the 'Find unmatched rows' query wizard to compare the two tables and find the number of rows which are same (and different). But the problem is this makes the MS Access hang for huge tables (10 million+ rows).
Are there any settings that I can tweak so that Access does not hang? I am using ODBC connections to Sybase and SQL Server.
One more thing I noticed is when I right click on the SQL Server link table and click on open, it shows all the rows from the table. When I do the same for the Sybase one, it hangs and I have to close Access through Task Manager.
Some details:
Sybase version - 12.5.3
SQL Server version - 2008 R2
MS Access Version - 2003
On the face of it I would say the problem is that access is trying to do this query locally and is pulling most of the table down the wire. This is where you often get the myth that access does this all of the time when in fact it only does it on certain edge events. Is there anyway you could narrow down the data you are comparing? Maybe the table is a list of product sales and you could do one product line at a time or something like that?
This involves data replication, kind of:
We have many sites with SQL Express installed, there is an 'audit' database on each site that has one table in 1st normal form (to make life simple :)
Now I need to get this table from each site, and copy the contents (say, with a Date Time Value > 1/1/200 00:00, but this will change obviously) and copy it to a big 'super table' in sql server proper, that also has the primary key as the Site Name (That needs injecting in) and the current primary key from the SQL Express table)
e.g. Many SQL Express DBs with the following table columns
ID, Definition Name, Definition Type, DateTime, Success, NvarChar1, NvarChar2 etc etc etc
And the big super table needs to have:
SiteName, ID, Definition Name, Definition Type, DateTime, Success, NvarChar1, NvarChar2 etc etc etc
Where items in bold are the primary key(s)
Is there a Microsoft (or non MS I suppose) app/tool/thing to manager copying all this data accross already, or do we need to write our own?
Many thanks.
You can use SSIS (which comes with SQL Server) to populate, it can be set up with variables to change the connection string to the various databases. I have one that loops through the whole list and does the same process using three differnt files from three differnt vendors. You could so something simliar to loop through the different site databases. Put the whole list of database you want to copy the audit data from in a table and loop through it changing the connection string each time.
However, why on earth would you want one mega audit table per site? If every table in the database populates the audit table as changes happen, then the audit table eventually becomes a huge problem for performance. Every insert, update and delete has to hit this table and then you are proposing to add an export on top of that. This seems to me to be a guaranteed structure for locking and deadlocks and all sorts of nastiness. Do yourself a favor and limit each audit table to the table it is auditing.
Things to consider:
Linked servers and sp_msforeachdb as part of a do-it-yourself solution.
SQL Server Replication (by Microsoft) (which I believe can pull data from SQL Server Express)
SQL Server Integration Services which can pull data from SQL Server Express instances.
Personally, I would investigate Integration Services first.
Good luck.
You could do this with SymmetricDS. SymmetricDS is open source, web-enabled, database independent, data synchronization/replication software. It uses web and database technologies to replicate tables between relational databases in near real time. The software was designed to scale for a large number of databases, work across low-bandwidth connections, and withstand periods of network outage.
As of right now, however, you would need to implement a custom IDataLoaderFilter extension point (in Java) to add the extra column. The metadata would be available though because your SiteName would be the external_id.