In MS Access SQL Server Linked Table pass through query - sql-server

I have a query against a linked table in MS Access that uses the getdate() function of SQL Server. However, I get this error when I attempt to run the query:
Undefined function GetDate in function
How do I create a linked table that allows the use of SQL Server T-SQL syntax? I see that this is called a pass through query but I don't know how to set it up to use the connection on the linked table as a pass through query.
Currently using Access 2010. The query is:
select getdate()
If it helps, I used the following vba code that generates the table link to SQL Server:
Function LinkTable(LinkedTableAlias As String, Server As String, Database As String, SourceTableName As String, OverwriteIfExists As Boolean, Username As String, Password As String)
'This method will also update the link if the underlying table definition has been modified.
If (InStr(1, LinkedTableAlias, "MSys") > 0) Then
Log "Skipping " & LinkedTableAlias
Exit Function
End If
'The overwrite parameter will cause it to re-map/refresh the link for LinktedTable Alias, but only if it was already a linked table.
' it will not overwrite an existing query or local table with the name specified in LinkedTableAlias.
'Links to a SQL Server table without the need to set up a DSN in the ODBC Console.
Dim tdfLinked As DAO.TableDef
' Open a database to which a linked table can be appended.
Dim dbsCurrent As Database
Set dbsCurrent = CurrentDb()
'Check for and deal with the scenario ofthe table alias already existing
If TableNameInUse(LinkedTableAlias) Then
'If InStr(dbsCurrent.TableDefs(LinkedTableAlias).Connect, "AccessBackup") Then
' Exit Function
'End If
If (Not OverwriteIfExists) Then
Log "Can't use name '" + LinkedTableAlias + "' because it would overwrite existing table."
Exit Function
End If
'delete existing table, but only if it is a linked table
'If IsLinkedTable(LinkedTableAlias) Then
dbsCurrent.TableDefs.Delete LinkedTableAlias
dbsCurrent.TableDefs.Refresh
'Else
' Log "Can't use name '" + LinkedTableAlias + "' because it would overwrite an existing query or local table."
' Exit Function
'End If
End If
'Create a linked table
Set tdfLinked = dbsCurrent.CreateTableDef(LinkedTableAlias)
tdfLinked.SourceTableName = SourceTableName
tdfLinked.Connect = "ODBC;DRIVER={SQL Server};SERVER=" & Server & ";DATABASE=" & Database & ";UID=" & Username & ";PWD=" & Password & ";"
On Error Resume Next
dbsCurrent.TableDefs.Append tdfLinked
If (err.Number = 3626) Then 'too many indexes on source table for Access
err.Clear
On Error GoTo 0
If LinkTable(LinkedTableAlias, Server, Database, "vw" & SourceTableName, OverwriteIfExists, Username, Password) Then
Log "Can't link directly to table '" + SourceTableName + "' because it contains too many indexes for Access to handle. Linked to view '" & "vw" & SourceTableName & "' instead."
LinkTable = True
Else
Log "Can't link table '" + SourceTableName + "' because it contains too many indexes for Access to handle. Create a view named '" & "vw" & SourceTableName & "' that selects all rows/columns from '" & SourceTableName & "' and try again to circumvent this."
LinkTable = False
End If
Exit Function
End If
On Error GoTo 0
'** Turn on error handling
On Error GoTo ErrorHandler:
tdfLinked.RefreshLink
LinkTable = True
Exit Function
ErrorHandler:
Log "refreshlink failed for " & tdfLinked.Name
LinkTable = True

I don't quite understand this statement:
How to I create a linked table that allows the use of SQL Server T-SQL
syntax?
But this is how you convert an existing MS Access querydef to a pass through query:
Go to design mode in the query, press the Query menu command, then SQL Specific then Pass Through
See this for screenshots.
http://www.mssqltips.com/sqlservertip/1482/microsoft-access-pass-through-queries-to-sql-server/

The reason why you are getting the error is that GETDATE() is not a function inside MSAccess. You probably need Now() to get the date and time or you may use Date() which provides the date

Here's a quick and dirty VBA way to create a pass-through query:
Set qdf = CurrentDb.CreateQueryDef("testqry")
' this is just your connection string
qdf.Connect = "ODBC;Driver={SQL Server};Server=MSSQL1; Database=MyDB;Trusted_Connection=Yes"
'anything here gets passed directly to and executed on the SQL Server
qdf.SQL = "select getdate()"
Set qdf = Nothing
Now you can use "testqry" as if it's any other Access query (as far as SELECTing from it goes, anyway)

Simple save your t-sql query as a pass-though
Select GetDate()
Then in VBA code, you can go:
TheSqlDate = currentdb.QueryDefs("qPass").OpenRecordset()(0)
Using ADO, and hardcoding connection strings, and the HUGE whacks of other code posted here is just a way to rack up billable hours and create world poveity. My posted solution IS ONLY ONE LINE OF CODE!

Related

Set commandtimeout for linked SQL Tables/Views in Access front end

We have moved some back-end data tables over from a network drive (mbd file) to being on an SQL Server database. Things mostly work great, but if staff are accessing things through a VPN (which slows things down a lot), then we get connection errors when we run reports that retrieve a lot of data. My guess is that I need to set a timeout to a larger value, and I did some research and it seems that I need to set the commandtimeout (or maybe query timeout?).
Below is the VBA code we use to connect the SQL Server tables/views to our Access front end from the SQL Server back end. Am I right that I likely need to specify a commandtimeout? Where in this would we add the commandtimeout (or other timeout) value?
Public Sub CreateSQLLinkedTable(strSourceTableName As String, strNewTableName As String)
'************************************************************************************
'* Create a linked table in the current database from a table in a different SQL Server file.
'* In: *
'* strNewTableName - name of linked table to create *
'* strSourceTableName - name of table in database *
'************************************************************************************
Setup:
Dim tdf As TableDef
Dim strConnect As String, strMsg As String
Dim myDB As Database
' set database vars
Set myDB = CurrentDb
Set tdf = myDB.CreateTableDef(strNewTableName)
MakeConnections:
On Error GoTo OnError
' turn system warnings off
DoCmd.SetWarnings False
' define connect string and source table
' We do not need to specify the username (Uid) and password (Pwd) in this connection
' string, because that information is already cached from the connection to the SQL
' Projects database that we created in CheckSQLConnection() that was run to check connection
' to the database. So here we can have a connection string without the Uid and Pwd.
With tdf
.Connect = "ODBC;Driver={SQL Server};" & _
"server=" & myServer & ";" & _
"database=" & mySQLDB & ";"
.SourceTableName = strSourceTableName
End With
' execute appending the table
myDB.TableDefs.Append tdf
' turn system warnings back on
DoCmd.SetWarnings True
ExitProgram:
' this block of code will run if there are no errors
Exit Sub
OnError:
' this block of code runs if there is an error, per On Error assignment above
' display error message with details
MsgBox "There was an error connecting to the SQL Server data source Projects. Error = " & err & ", Description: " & err.Description
'exit Projects
Call CloseFormsAndQuit
End Sub
There is an ODBC timeout property. Open the query in design view, and go to properties to see it. There is also an (ODBC) query timeout on the current database properties page. You can set it programmatically as well:
Dim objDB As DAO.Database
Set objDB = CurrentDb()
objDB.QueryTimeout = 120
http://www.geeksengine.com/article/how-to-change-timeout-value-for-access-sql.html
Also check the server configuration. There is a query timeout on server side.

Create database in SQL Server (only once) using VBA Excel

I would like to create a database in SQL server using VBA (Excel) just the first time that I will run the code. So the second time I run the code, the database will exist, and it will not create another one.
#abarisone
`Public Sub CreateDBTable()
Dim dbConnectStr As String
Dim Catalog As Object
Dim cnt As ADODB.Connection
Dim dbName As String
Dim tblName As String, ServerName As String, UserID As String, pw As String
tblName = shControl.Range("B5") 'Table Name
ServerName = "SERVICESWS15" 'Enter Server Name or IP
dbName = shControl.Range("B4") 'Enter Database Name
UserID = "" 'Leave blank for Windows Authentification
pw = "" 'Leave blank for Windows Authentification
dbConnectStr = "Provider=SQLOLEDB;Data Source=" & ServerName & ";Initial Catalog=" & dbName & ";User Id=" & UserID & ";Password=" & pw & ";"
Set Catalog = CreateObject("ADOX.Catalog")
Catalog.Create dbConnectStr
Set Catalog = Nothing
Set cnt = New ADODB.Connection
With cnt
.Open dbConnectStr
.Execute "CREATE TABLE " & tblName & " (KEY nvarchar(100) NOT NULL, " & _
"Date nvarchar(100) NOT NULL, " & _
"PRIMARY KEY (KEY));"
End With
Set cnt = Nothing
End Sub
`
There is an error in this line:
Catalog.Create dbConnectStr
Error: No such interface supported
It's not very complicated. First make sure that you are referring to the appropriate ADO library like here on the screenshot.
Then your have certain building blocks you will have to use: first make a Connection object (with a connection string), then make a Command object, and last but not least use the ExecuteNonQuery method of Command on your connection object. It does what the name says: executes an SQL command without having a RecordSet as a return object. See examples in the documentation starting from here.
I have not tried it before, but for this to happen without error, you will probably have to set your connection string to the system database called "Master" if working on MS SQL Server.
Of course, the SQL commands you will have to execute are (1) check if the database exists, (2) create db and tables if not.
Then you can create your "normal" Connection object to your database.
WARNING: to be able to create a database, your technical user defined in the VBA script must have high (system admin) privileges which is definitely a HUGE RISK even if you protect your excel. If it's not a sandbox environment, DO NOT DO IT!

For Each If Statement - Skip NULLs

I have created a macro/some VBA to UPDATE a SQL Server table which works fine.
In short the code pulls a defined amount of records from the the table to excel and then the end user updates some specific information and then clicks update. A connection is created to the table and an SQL update statement runs which updates the relevant records.
The problem is where the user has not had to update a NULL field (NULL is in the SQL Server table but shows as 'empty' in Excel), when the use clicks update the SQL statement is forcing the NULL to an 'empty' entry.
To get round this I would like my code in the For Each statement to check if the cell/record is NULL or Empty and to skip to the NEXT row so the SQL Execute command is not carried out.
Here is the VBA in question:
cnn.Open cnnstr
Dim row As Range
For Each row In [tbl_data].Rows
uSQL = "UPDATE BREACH_DATA SET [VAL_BREACH_REASON] = '" & (row.Columns(row.ListObject.ListColumns("VAL_BREACH_REASON").Index).Value) _
& "' ,[VAL_BREACH_DETAIL] = '" & (row.Columns(row.ListObject.ListColumns("VAL_BREACH_DETAIL").Index).Value) _
& "' ,[VAL_VALID] = '" & (row.Columns(row.ListObject.ListColumns("VAL_VALID").Index).Value) _
& "' ,[VAL_NOTES] = '" & (row.Columns(row.ListObject.ListColumns("VAL_NOTES").Index).Value) _
& "' WHERE [ATD_NUMBER] = '" & (row.Columns(row.ListObject.ListColumns("ATD_NUMBER").Index).Value) & "'"
'Debug.Print uSQL
cnn.Execute uSQL
Next
cnn.Close
Set cnn = Nothing
Any suggestions
Kind Regards
Dino
You are updating SQL Server data directly with strings from a cell. This is a classic example of opening a door for injection attacks - users can do all kinds of bad, bad things to your database. But given that you fix that here is a way to check that each cell is not empty or null (I assume if one of the fields are not empty or null you want to update...):
if not
(
(isempty(row.Columns(row.ListObject.ListColumns("VAL_BREACH_REASON").Index).Value)
and isnull(row.Columns(row.ListObject.ListColumns("VAL_BREACH_REASON").Index).Value)
and do same for the other cell values....
)
then update....

Changing DROP TABLE code to APPEND/INSERT

This code currently is using a DROP TABLE to transfer data from Access to SQL Server, that is when it was intended for one person to use. Now it is going to be used by multiple people so I need to alter the code to APPEND. I am trying to figure out how to get it to check the destination table to see if the record already exists, if it does it will skip over it, if not it will write that employees data to the table. The SQL table is prebuilt and it has a ROW ID column and TIME STAMP column that the access table does not have in order to keep track of the records being entered.
The code currently looks like:
Public Function Update()
Dim cdb As DAO.Database, qdf As DAO.QueryDef
Dim err As DAO.Error
Const DestinationTableName = "AC_CDData"
Const ConnectionString = _
"ODBC;" & _
"Driver={SQL Server Native Client 10.0};" & _
"Server=SERVER;" & _
"Database=DB;" & _
"UID=ID;" & _
"PWD=PW;"
Set cdb = CurrentDb
Set qdf = cdb.CreateQueryDef("")
qdf.Connect = ConnectionString
qdf.SQL = _
"IF EXISTS " & _
"(" & _
"SELECT * FROM INFORMATION_SCHEMA.TABLES " & _
"WHERE TABLE_NAME='" & DestinationTableName & " '" & _
") " & _
"DROP TABLE [" & DestinationTableName & "]"
qdf.ReturnsRecords = False
On Error GoTo Update_qdfError
qdf.Execute dbFailOnError
On Error GoTo 0
Set qdf = Nothing
Set cdb = Nothing
DoCmd.TransferDatabase _
acExport, _
"ODBC Database", _
ConnectionString, _
acTable, _
"CDData", _
DestinationTableName, _
False
Exit Function
Update_qdfError:
For Each err In DAO.Errors
MsgBox err.Description, vbCritical, "Error " & err.Number
Next
End Function
The DoCmd.TransferDatabase does a complete transfer of the data from the Access table, to the SQL Server database. This function can not do partial inserts based on existing records.
What you can do, however, is export the data into a temporary new table (without dropping the existing table), followed by executing an SQL MERGE statement, to incorporate the new records of the temporary table, with the existing table.
You'll need to know how to perform SQL queries from VBA against your SQL database, and you'll need to know how to use the SQL MERGE statement. A google search will quickly give you the answer to both.
Just setup a simple standared linked table to SQL server in Access.
Since the column of the existing record is a primary key (or simply an index set = unique), then you only need ONE LINE of code to append your data.
This will work:
CurrentDb.Execute "INSERT INTO AC_CDData SELECT * FROM CDData;"
Any row that already exists will be ignored due to key (or index) violation. Thus only new non existing records will be appended with the above one line of code.
Edit:
As for the target table being a SQL linked table? Your application on startup does not care if you have some linked tables. Your application does not use nor care about such linked tables unless you use them.
The assuming here is you have a local data table. The linked table ONLY comes into play when you going to do the export. As noted you cannot export unless you are connected to SQL server. The “code” or testing if you are connected is not dealt with in this question but even if it was part of the question in both cases you still have to test for a connection and once again when you do finally determine you have a connect and you decide to export then again the linked table as per above will work.
So there is really no reason I can think of as to why having a linked table that is ONLY used during the append to the SQL table will be any kind of issue or problem.
As stated, then the one line of VBA code should suffice here.
In case of concurrent usage the process need to be changed:
DestinationTableName must be unique per session (thread) and need to be changed (from constant to variable)
Tabel with DestinationTableName neame need and need to be dropped before the export data (as it was in current solution).
DoCmd.TransferDatabase will not change - the data will be exported into the unique temp table.
For simplifying the Merge process the stored procedure can be written on the SQL Server side (with all needed to APSERT logic) with the source table name as parameter. This SP need to be called after the DoCmd.TransferDatabase completion
In this case the flow will be the following:
DestinationTableName unique name generation
Dropping this table on the SQL Server side (qdf.Execute ...)
Export data to the temp table (DoCmd.TransferDatabase ...)
Merge data in the SQL Server side (call to created SP with needed logic of update / insert)

Programmatically creating linked tables in access

We need to find a way to programatically ****link all the tables in a SQL Server database to an access db. We will be invoking this access database from a program that uses .net/SQL Server 2008.
While invoking the application we would like to add the linked tables so that the users can just run the reports/modules from access without having to worry about linking the tables. Is there a way we can do this?
Here are some notes.
Dim sLocalName As String
Dim tdf As TableDef
Dim rs As dao.Recordset
''This is a basic connection string, you may need to consider password and so forth
cn = "ODBC;DSN=TheDSNName;Trusted_Connection=Yes;APP=Microsoft Office 2010;DATABASE=TheDatabaseName;"
''All fields from tables
strSQL = "SELECT TABLE_CATALOG, " _
& "TABLE_SCHEMA, " _
& "TABLE_NAME, " _
& "TABLE_TYPE " _
& "FROM [" & cn & "].INFORMATION_SCHEMA.tables " _
& "WHERE TABLE_TYPE = 'BASE TABLE'"
Set rs = CurrentDb.OpenRecordset(strSQL)
Do While Not rs.EOF
sLocalName = rs!TABLE_SCHEMA & "_" & rs!TABLE_NAME
With CurrentDb
If DLookup("Name", "MSysObjects", "Name='" & sLocalName & "'") <> vbNullString Then
If .TableDefs(sLocalName).Connect <> cn Then
.TableDefs(sLocalName).Connect = cn
.TableDefs(sLocalName).RefreshLink
End If
Else
''If the table does not have a unique index, you will neded to create one
''if you wish to update.
Set tdf = .CreateTableDef(sLocalName)
tdf.Connect = cn
tdf.SourceTableName = rs!TABLE_NAME
.TableDefs.Append tdf
.TableDefs.Refresh
''This will produce a message box if the table does not have a unique index
''DoCmd.TransferDatabase acLink, "ODBC Database", cn, acTable, rs!TABLE_NAME, sLocalName
End If
End With
rs.MoveNext
Loop
You'll need an ODBC connection to the SQL database. Once this connection ready, you can use it for all tables that you want to link:
DoCmd.TransferDatabase acLink, _
"ODBC Database", _
myODBCconnection, _
myDatabaseName, _
acTable, _
myTableName
I guess you can declare your ODBC connector "on the fly", as proposed here for example.
To enumerate your tables, you have the following options:
Enumerate them in the code: one transferDatabase line per table
Save the table names in a local table, and browse the table
Save the table names in a file (text, xml) anywhere on the network and browse the file
Access the system table on the server that holds the table list, and browse the table
Use the ADOX object to browse all tables in your database server: be carefull not to include system tables. This solution might be also quite confusing because you'll have to first open an ADODB connection to your database, and you'll then use an ODBC connection to open the tables
In all cases, this procedure shall be launched with the autoexec macro, meaning that links will be created\updated each time the user opens the mdb client.
You would use ADOX to do the actual linking.
As far as enumerating the tables in a database you are connected to, you could do something as simple as running this query against your SQL Server, but there are a lot of ways to skin that cat:
SELECT * FROM INFORMATION_SCHEMA.TABLES
You can achieve the equivalent by using a Linked Server in SQL Server that points to the Access db. This will give you access to all the tables in the Access db so that you can reference them like:
Select ..
From [LinkedServerName]...[AccessTableName]
Btw, a linked server may be overkill for what you want. Look into the OPENROWSET function which effectively let's you pass a connection string.
EDIT: I originally read the question to literally mean "link tables in SQL Server to access" which I translated to mean from SQL to Access. So, given that, my solution would apply. However, if the desire is to go from Access to SQL, then that is different and other solutions presented would be more appropriate.

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