I have imported a table in Access 2007 through Oracle ODBC. My problem is that sometimes the tables change structure in Oracle (eg new columns are added) and when that happens Access doesn't automatically pick up the changes in its linked table.
Instead it keeps using the old structure and even worse some rows simply won't show up in the Access queries (I don't know why?).
The other problem is that I don't have any control over the Oracle DB so the changes can happen any time. Manually updating the linked tables all the time is too much of a hassle. Is it possible to somehow set Access up to notify me of the changes? I mean, somehow Access must be able to tell that something has changed - the question is; can it tell me?
Regards,
John
Run this function - you can either link it to a form Open event, or just run it when you need to refresh the data
Sub relinkTables()
Dim tdf As DAO.TableDef
For Each tdf In CurrentDb.TableDefs
' check if table is a linked table
If Len(tdf.Connect) > 0 Then
tdf.Connect = "your odbc connection string to the DSN or database"
tdf.RefreshLink
End If
Next
End Sub
Related
My current team of 20 people uses an access database front end on their desktop. The backend of the access database is on a network drive. I have been asked to create an access database front end with MYSQL as the back end.
I have installed the MySQL workbench and the ODBC connector on my computer. I have created the schema and tables and I have connected the front end of the database connected to the MYSQL table I created in workbench. My question is
How do I deploy this for the team to use. I believe I can move the front end of the access dB to the network drive and the team can copy it to their desktop. But what do I do about the backend?
Does the team need to have the ODBC connector installed on their computers?
Should I move the MySQL workbench to the network drive?
PS: I am a new developer and just learning about databases and I am only familiar with the access database please go easy on me.
Thanks.
SO is for questions about coding, so this is OT. However:
One method is described in my article:
Deploy and update a Microsoft Access application with one click.
The old backend, you can archive. It will not be used anymore.
Yes.
Probably not. It is only for you, should you need to modify the
MySQL database.
Well, first up, you STILL need and want to deploy the application part called the front end (FE) to each workstation.
So, after you migrate the data to MySQL, then of course you will use the access linked table manager, and now link the tables to MySQL. How this works is really much the same as you have now. The only difference is that you linked tables now point to the database server (MySQL). From the application point of view, it should work as before.
Like all applications, be it Outlook, Excel, accounting packages? You STILL deploy the application part to each workstation. So just because YOU are now developing and writing software with Access does not mean out of the blue that you now for some strange reason STOP deploying the FE part to each workstation. In fact, you should be deploying a compiled version of your application (a accDE).
A few more tips:
WHEN you link the FE, MAKE SURE you use a FILE dsn. The reason for this is Access converts the links to DSN-less for you. What this means is that once you link the tables, then you are free to deploy the FE to each workstation and it will retain the linked table information WITHOUT you having to setup a DSN connection on each workstation. You will also have to of course deploy the MySQL ODBC driver to each workstation as that is not part of Access nor it is part of your application.
So just because you are now developing software does not suggest nor get you off the hook of deploying that application to each workstation. So, your setup you have now with a FE on each workstation does NOT change one bit.
For the most part, after you migrate the data to MySQL, then likely setup your relationships (say with MySQL workbench) there are several other things you need to keep in mind.
All tables now need a primary key. You likely have this, but Access with a access back end did and could work on tables without a PK. However, for SQL server/MySQL etc., then all tables need that PK.
Next up:
If you have any true/false columns, you MUST set a default up for that column. If such true/false columns have a default value or allow nulls, this will confuse access - so ensure that true/false columns can't have nulls and have default (useally 0) setup on the server side.
Add a "rowversion" column. This is not to be confused with a datetime column. In SQL server this rowversion column is of timestamp data type (a poor name, since the column has zero to do with time - it is simply a column that "versions" the row. This will also eliminate many errors. I don't know what this type of column is called in MySQL, but all tables should have this column (there is zero need to see/use/look at this column on your forms - but it should be part of the table.
All of your forms, reports and code should work as before. For VBA recordset code, you need this:
dim rst DAO.Recordset
dim strSQL as string
strSQL = "SELECT * from tblHotels"
set rst = currentdb.OpenRecordSet(strSQL).
You likely in the past had lots of code as per above.
You now need:
Set rst = CurrentDb.OpenRecordset(strSQL, dbOpenDynaset, dbSeeChanges)
You can generaly do a search and replace (find each .OpenRecordSet, and add the dbOpen and dbSee to each line of code you find. (I put the dbOpenDynaset, dbSeeChanges in my paste buffer. And then do a system wide search. It takes a few minutes at most to find all .openRecordSets
At this point, 99% of your code, forms and everything should work.
The ONE got ya?
In access be it on a form or in VBA recordSet code? When you create a new row, or start typing on/in a form? Access with access back end would generate the PK at that point. There was/is no need to save the record to get the PK value. This need is rare, and in a large application I only had about 2 or 3 places where this occured.
So, if you have code like this:
dim rstRecords as RecordSet
dim lngPK as Long ' get PK value of new record
Set rstRecords = CurrentDb.OpenRecordset("tblHotels")
rstRecords.AddNew
' code here sets/ add data/ set values
rstRecords!HotelName = "Mount top Hotel"
rstRecords!City = "Jasper"
' get PK of this new record
lngPK = rstRecods!ID ' get PK
rstRecords.Update
So, in above code, I am grabbing the PK value. But with server systems, you can NOT get the PK value until AFTER the record been saved. So, you have to change above to
rstRecords.Update
rstRecords.Bookmark = rstRecords.LastModified
' get PK of this new record
lngPK = rstRecods!ID ' get PK
Note how we grab/get the PK AFTER we save.
The bookmark above simply re-sets the record pointer to the new record. This is a "quirk" of DAO, and WHEN adding new reocrds, a .Update command moves the record pointer, and thus you move it back with the above .LastModified. You ONLY need the .LastMOdifed trick for NEW reocords. For existing, you already have the PK - so it don't matter.
This type of code is quite rare, but sometimes in a form (and not VBA reocdset code), some form code we might use/need/get/grab the PK value. In a form, you can do this:
if me.dirty = true then me.dirty = false ' save reocod
lngPK = me.ID ' get PK
So, once again, in the above form code, I make sure the record is saved first, and THEN I grab the PK value as above. Of course this is ONLY a issue for NEW records. (and you don't have to use the bookmark trick - that's only for recrodsets - not bound forms.
So, just keep in mind in the few cases when you need the PK value of a NEW record, you have to do this AFTER you saved the recordset (update) or in the case of a form, after you forced a form record save. This requirement is only for new records and ALSO only when your code needs to get/grab the new PK value.
Other then the above two issues? All the rest of your existing code and forms should work as before.
I have an Access Database connected(linked table) to an Oracle database.
I wrote some Select queries. Everytime I run it, I get an "Oracle ODBC Driver Connect" input box.
Is there way to write a vba macro to enter username and password (auto fill) and Enter Ok.
Trying to set up an auto run for macros in this Access db.
Any help is appreciated.
As pointed out, when you link the tables, you are given an option to save the password in those table links. If you missed this step, then you will get that ODBC prompt.
THIS HAS ZERO to do with you writing select queries. The simple matter is try clicking on one of the linked tables you use in such quires. Either you get an ODBC prompt or you do not.
If you do, then of course you going to get such a prompt when you write a query. YOU WANT to FIRST get the table links working without an ODBC prompt and THEN write those queries based on the linked tables.
So get the linked tables working first. Forget about and don’t’ worry about your queries you are writing. Until such time that a simple click on (opening) a linked table works and does not throw out the ODBC prompt, then you are looking at the WRONG problem.
Once you get your linked tables working without a prompt, then your queries will also work without a prompt.
So you have two choices to fix this problem.
Simple re-link your tables, and ensure that you select [x] check box during re-link to save the password.
The prompt you missed and want to select is this one:
Now if your tables are already linked and you run the linked table manger, you WILL NOT get this prompt anymore. So you have to delete the table links, and re-create.
Of course deleting the table links can often result in the linked table names being changed, and that can be a pain, especially if you have a LOT of linked tables. Only you can make this judgement call as to what is less work. If you have just a few tables, then just delete them, and use the external data -> then in the import and link secton, choose ODBC and you can add the tables, but REMEMBER to select (check) the above save password box as per above that you missed.
Now, most people over time wind up with some table re-link code VBA. So if you have suc re-link code already working and handy, then simply re-run that code with the user/password included in the connection string you use in that code. Of course if you don't have such code, then the above linked table manager in Access is a code free solution and is obviously your best choice and course of action.
So in place of above, you can find some table re-link code that will force (save) the user/id in the table links for you.
However, if you don’t want to delete + re-create all those tables, and you don’t have already setup some re-link code, there is also another (3rd) choice.
In your application start-up code simple execute a one-time logon. If you do this, then the ODBC prompt will not appear when you use the linked tables and hence also not appear when you attempt to run/build/use a query based on those linked tables.
The code to execute a one-time logon will look like this:
Function TestLogin(strCon As String) As Boolean
On Error GoTo TestError
Dim dbs As DAO.Database
Dim qdf As DAO.QueryDef
Set dbs = CurrentDb()
Set qdf = dbs.CreateQueryDef("")
qdf.connect = strCon
qdf.ReturnsRecords = False
'Any VALID SQL statement that runs on server will work below.
' this does assume user has enough rights to query built in
' system tables
qdf.sql = "SELECT 1 "
qdf.Execute
TestLogin = True
Exit Function
TestError:
TestLogin = False
Exit Function
End Function
Above code run ONE time on start-up of your application will thus eliminate the ODBC prompt(s) when you click on a linked table. And of course once that issue of linked tables is resolved, then of course creating or clicking on your query or running those quires will now ALSO work without the prompts.
You can NOT auto fill that prompt, you have to take CORRECT steps in the first place to PREVENT that prompt from appearing. So to answer your question?
No, you can't write code to enter the requested prompt, but if you link your tables with the password saved, or execute the above logon code, the prompt will NOT appear in the first place.
I have an access database with a form that runs 6 queries based on inputted values. A coworker went in to edit a query and instead of displaying the full query, Access is displaying the following
SELECT * FROM table WHERE 1 <> 1
I’ve tried opening a backup copy on a different computer as well as running Compact & Repair to no avail. The form is still running correctly, however.
Running Access 2016 and files displayed fine yesterday afternoon.
It's hard to say what happened without more details, but some queries can't be represented in design view. Editing such a query in design view trashes it.
Anyway, the query is lost. If you don't have a backup, you're out of luck. (Very rarely a temporary query still exists, you can iterate through the querydefs collection to view the SQL of all queries including temporary ones).
This doesn't solve the problem (sorry, not sure what's happened) but should let you retrieve the SQL if the query still runs as expected.
Erm... basically what #ErikvonAsmuth just suggested. :)
Public Sub Test()
Dim db As DAO.Database
Dim qdf As DAO.QueryDef
Set db = CurrentDb
Set qdf = db.QueryDefs("MyQueryName")
Debug.Print qdf.SQL
End Sub
I have an MS Access database with six (6) ODBC tables from Intuit QuickBooks Enterprise. I created the links manually, and they worked fine right off the bat. However, the links need to be refreshed daily. I attempted to write a VBA code to automate this process, however using tdf.RefreshLinks always failed. I always have to manually refresh the links. I discovered that the database name changes daily. Once it's refreshed, it's refreshed the rest of the day no matter if the PC is restarted or not. However, the next day the name is always different. This must be something that QuickBooks does. I think I need to be able to "grab" this database name in order to make my code work successfully. Has anyone ever heard of this? Does anyone know how to overcome this so that I can script the refreshing of the links, instead of manually refreshing them?
Since I have no reputation on this site, I am unable to post any images. But I can explain that my MSysObjects query shows the QuickBooks linked tables database name to be 33c292ce6be44bdca0cc8dd6c68594a0 and when I go to create a new link manually, the Connect to SQL Anywhere dialog box reveals on the Database tab the new day's database name: 4b2444e2c7ff4c37aa53d12a648f2fa0. I know once I refresh the links, this will be the database name that shows up in my MSysObjects query for the rest of the day. How do I get this so I can incorporate into VBA code? If this is truly the answer to automating the refreshing of the links?
RefreshLink should work fine:
Dim db As DAO.Database, tdf As DAO.TableDef
Dim cnn As ADODB.Connection
Set cnn = New ADODB.Connection ' cnn as in connection
On Error Resume Next
cnn.Open YOURCONNECTIONSTRINGHERE
Set db = CurrentDb
For each tdf in db.TableDefs
tdf.Connect = YOURCONNECTIONSTRINGHERE
tdf.RefreshLink
Next tdf
db.Close
Set db = Nothing
Is it possible via code to programmatically (from .NET for example via SQL query) to ask an Access database if it is corrupt or have tables with corrupt rows in it?
//Andy
None of the application/database level objects have such an "isCorrupted" property.
Furthermore, corrupted databases do not have a standard behaviour. Depending on the situation, database might not open at all (file is not recognized as a valid mdb file). If it opens, error might occur immediately or when using/opening a specific object (table, form, or VBA code).
In these conditions, I do not think there is a positive answer to your question.
Note: In addition to the standard compact/repair option of Access, exporting object to other databases (or importing them from the corrupted database) as well as the non-documented .saveAsText command can be of great help.
Here is some VBA that can be used to check for an error in previous releases of Access. It may also suit 2007.
Sub CheckForErr(tablename)
Dim rs As dao.Recordset
Dim db As Database
Set db = CurrentDb
Set rs = db.OpenRecordset(tname)
With rs
Do While Not .EOF
For Each fld In rs.Fields
If IsError(rs(fld.Name)) Then
Debug.Print "Error"
End If
Next
.MoveNext
Loop
End With
rs.Close
Set rs = Nothing
End Sub
We had network issues causing corruption in an access database on our shared drive and I spent a lot of time cleaning up corrupted rows from a couple specific tables.
The memo fields in particular were a good indication of corruption because they are not stored inline like the rest of the data but are kept in a separate table. I could open up the corrupted table in datasheet mode and try to determine which rows were corrupted by putting the focus on a corrupted memo cell--if there was corruption then I would immediately get an error.
Corrupted Int and Date columns would have odd values (3/18/1890, -11100910, etc.) but would not actually throw any errors when I read their values.
This is why cycling through all records and fields in the database as shown in the VBA from a previous answer makes some sense but will perform most reliably only if you have memo field corruption.