I have created a data entry application that works like this. All data entered goes in to an ACCESS table. At any time the user can hit the update button and the new data in the ACCESS table updates a table in a SQL Server data base. Recently, we have a need for multiple people to be doing data entry at the same time, and I am a bit confused about what is happening with the ACCESS table. I conducted experiments with two users updating the access table then closing the app before updating and after updating. My question is this: everything seems to work fine, no data is missing from either the ACCESS table or the SQL Server table. This begs the question of where does the ACCESS table reside when two versions of the app are open at the same time. Are there two versions of the ACCESS table or just one version that is used by both applications. I think it's the latter but I am not sure, because when we hit the update button on one users pc the data from both users is updated. I am trying to decide if I need to put the ACCES table up on SQL SERVER as well but would like to avoid the extra work.
Thanks
JPL
Related
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.
It's my first time creating an audit log for a PoS WPF application and was wondering on how exactly do I implement an auditing system because it seems like each option available has its ups and downs. So far from reading numerous articles/threads, I've narrowed down a few common practices on audit logs:
1. Triggers - Unfortunately, due to the nature of my app, I can't make use of triggers as it has no way of knowing which user has done the action. So what I did instead was to create a Stored Procedure which will handle the customer insert along with the customer log insert and its details. The Customer_Id will be provided by the application when using the Stored Procedure.
2. Have an old and new value - My initial plan was to only include the latter since I can reference its old value with the new value from the row before it but storing the the old and new value seemed more sensible, complexity-wise.
3. Use a separate database for the log / 4. Foreign Keys - This is probably my main concern, if I decide to use a separate database for the audit table, then I couldn't setup foreign keys for the customer and employee involved.
I created a mock-up erd with a master-detail table result to be shown on the wpf app to display the log to an admin and would really like your thoughts on possible problems that may arise (There's also an employee table but I forgot to put it):
https://ibb.co/dheaNK
Here's a few info that might be of help:
The database will reside together with the wpf app, which is a single computer.
The amount of customers will be less than 1000.
The amount of regular employees will be 3.
The amount of admins will be 2.
You can enable CDC Change Data Capture on SQL Server database for a specific table
This will enable you to collect all data changes on the database table logged in special tables.
You can also refer to official documents too
Here is a list of DML commands and how data changes are logged in the CDC table created for the source database table
What is good about CDC is it comes default with SQL Server and you don't have to do anything for logging. The only requirement is SQL Server Agent should be running so that the changes can be reflected on log table.
I have recently inherited a mess from the developer who used to sit in this chair over a year ago. One of the many things he did is create nearly identical tables in many databases (such as having a Users table in each database that contains exactly the same information). I am attempting to eliminate all the manual work that is currently being done every time a new employee is hired by eliminating these duplicate tables.
I have created a SQL view that represents data exactly as the old table did. It pulls it's data from the master database, but all the tables I need (and this new view) are all on the same DB. There is no need for the application I am working with to modify the users table, so it only needs read access (so a view should be fine, right?).
Is there any way to simply replace the table in code with the new view? I would be happy to provide more information if needed.
if the created view has the same name and same columns as the original table, it will work without app modification.
It is also possible to modify data throught this view (with some restrictions...), see https://msdn.microsoft.com/en-us/library/ms180800.aspx .
My form is housing the data I need it to, and I have gotten all the functions corrected. I am trying to figure out a way to get the data from the local access table to auto upload to a sql server db as long as there is an established connection, I was told record sets may be a good way to go. And I tried just linking the table but that is not what my boss is looking for. ANy ideas or direction would be greatly appreciated.
The data housed is employee data, each time it uploads I just need it to push all data regardless if its new or not onto the same table, it will be overwritten. THe data now is saved to a local table whenever the form is filled out, so if it can connect it needs to upload and if it cannot then it just sits and continues to sit on the local table.
You need to create the destination table on SQLserver and link it to your access solution as an ODBC connected table. Also create an insert query that writes from your local table to the ODBC table.
Now you simply need to trigger that insert query (for example CurrentDB.execute ) during a fitting event in your form (open, close, before_update etc.).
When first time I created my App, I created a Database using Microsoft SQL SERVER Management Studio and I connected my App with it.
I created another DB with the same tables and every thing but with diferent names and I let my App to connect to the second one because I want to make some changes and when I am trying to edit my DataSet with Wizard I get this tables page :
as you can see my app couldn't find the right tables and when I am trying to select LastWork table as in the pic, it will make the table name in the DataSet LastWork1.
How I can fix this problem? and let it find the right tables
I've seen this problem when using copies of databases as well, after pointing to a different connection in the settings area of the project properties. The XSD evidently hard codes each DbObjectName with the name of the database and schema in use at design time. One approach to fixing it is to open the wizard for the appropriate dataset, uncheck the red-x objects with the missing references, close the wizard, then re-open it and re-select the objects that are needed. This is not ideal in a large xsd if many findby queries, custom columns, etc. have been added. So an alternative is to do a find and replace on the database name within the XSD itself.
Interestingly, my experience has been that an application runs fine when the connection string points to a differently named but otherwise identical database.