I am Making connection to Sql Database and in one connection i am changing my query many
times,This is the basic structure of my code.The structure works fine.
I have Following Questions
1) Is this the right method of sending different Query to Sql Database.
2) Will this cause any memory leaks or error.
dim conn
set conn=CreateObject("ADODB.Connection")
With conn
.Provider = "Microsoft.Jet.OLEDB.4.0"
.ConnectionString ="Data Source=C:\MAP_sample.xls;" & "Extended Properties=Excel 8.0;"
.Open
End With
Set rs = CreateObject("ADODB.Recordset")
Query = "SELECT * FROM [Sheet1$] where StateName='ABC'"
rs.Open Query,conn
rs.close
CHANGE THE QUERY
Query = "SELECT * FROM [Sheet1$] where ID='321'"
rs.Open Query,conn
rs.close
change the query
Query = "SELECT * FROM [Sheet1$] where NAME='SMITH'"
rs.Open Query,conn
rs.close
Set rs = nothing
conn.close
Set conn = nothing
looks like classic ASP with visual basic.
It is one of the possible variants to send queries, it is not bad, a little bit boilerplate, as suggestion - try to re-factor it into separate class or functions
No, it will no cause memory leaks or errors as you're calling close
You can later call the Open method to re-establish the connection to the same, or another, data source.
the only problem with this approach comes when you need to have 2 recordset opened at the same time
if you speak about general code readability - it is better to use meaningful variable names
Related
I have a PostgreSQL 9.5 database with an Access 2016 front-end, using an ODBC driver to connect the two. If I wanted to query data, I would start with the following commands:
Dim conn As New ADODB.Connection
conn.Open "Driver={PostgreSQL ANSI};Server=localhost;Database=[name];User Id=[UID];Password=[pass];"
Dim cmd As New ADODB.Command
cmd.ActiveConnection = conn
My question is this: Is there any reason why I shouldn't establish this connection the moment the application opens, using that connection whenever I need to run a query, as opposed to opening and closing the connection each time I run a query?
I'm unsure what, if any, overhead is involved in establishing such a connection in Access, and I've been unable to find any information on the topic. Apologies if this is a naive question.
I the connection is cached by Access anyway.
Once you touch, or open any linked table, then the connection is now active, and re-used by Access.
In general if the query is against a single table, then there little reason to not just code against the linked table.
Eg:
Dim rst As DAO.Recordset
Dim strSQL As String
strSQL = "select * from tblInvoices where invoiceNum = 13355"
Set rst = CurrentDb.OpenRecordset(strSQL)
If you using a pass-though query, then this works well:
Sub Test555()
Dim rst As DAO.Recordset
With CurrentDb.QueryDefs("qryPass")
.SQL = "select * from tblInvoices where invoiceNum = 13355"
Set rst = .OpenRecordset
End With
End Sub
The reason for above is you thus don’t mess or have to bother with connection strings in your code.
Just ensure that you table re-link code also re-links any pass-through query.
I am querying my access table using VBA and writing the query result in excel.
EOF is always true but BOF is False - even if the record count is 1 or 14 or 100. What possibly would be wrong? I can see the record count more than zero. get string value has data in it. Due to this there is no data written in the destination sheet except for Headers. The headers are coming in fine.
List of things tried but result was still same:
Added Move last and Move first command
Tried all possible combinations of Cursor location, cursor type, lock type
Tried with execute command
Tried with different MS access table
Tried early and late binding techniques
Below is my query and link below is my how my record set looks after SQL open statement.
Const MyConn = "Access DB location"
Dim con As ADODB.Connection
Dim rs As ADODB.Recordset
Set con = New ADODB.Connection
With con
.Provider = "Microsoft.ACE.OLEDB.12.0"
.Open MyConn
End With
QuerySql = "SELECT * FROM Store_Location"
Set rs = New ADODB.Recordset
rs.CursorLocation = adUseClient
rs.Open QuerySql, con, adOpenStatic, adLockReadOnly, adCmdUnknown
rs.MoveLast
rs.MoveFirst
i = 0
For i = 0 To rs.Fields.Count - 1
Sheets("Search_Temp").Cells(1, i + 1) = rs.Fields(i).Name
Next i
Range("A2").CopyFromRecordset rs
rs.Close
Set rs = Nothing
con.Close
Set con = Nothing
While debugging this is what my record set looks like:
Building on this answer to a similar question, calling getString on a Recordset object has a side-effect of moving the recordset to EOF.
You don't call getString anywhere in your code but you've added a watch on rs.getString which is visible as the last entry in the Watches window. If you have a watch on rs.getString and you have a breakpoint in the code where rs is open then that breakpoint will cause the recordset to move to EOF.
Depending on where the breakpoint occurs, this might not cause any issues (e.g. if the recordset was already at EOF) but, in this case, it is moving the recordset to EOF before you have copied the data from the recordset.
To solve this issue, remove the watch on rs.getString. It's probably a bad idea in general to have items in the Watches window cause side effects. You could also avoid the issue by not having any breakpoints where the recordset is open but removing the watch entirely is more robust.
The issue of getString moving the recordset to EOF isn't mentioned in the ADO documentation but it's easy to reproduce this effect.
It's uncommon for someone to include the entire list of watches they had set in their question but I'm not sure this question was answerable without that information
I am using MariaDB and VBA to read/write a flat database using ADODB. This is not by choice however I've been asked to make it work in this manner. An alternative would be to directly use SQL queries however this is a port of a very old VB3 application.
Here is my code that connects to the database, pulls back all records, updates the last record, then calls update to effectively write it back to the database
Global DB As New ADODB.Connection
Global TD As New ADODB.Recordset
DB.Open "Driver={MariaDB ODBC 2.0 Driver};Server=localhost;UID=???;PWD=???;DB=sf_log;Port=3306"
Dim query As String: query = "SELECT * FROM `" & TableName & "` ORDER BY `Record ID`"
TD.CursorLocation = adUseServer
TD.CursorType = adOpenDynamic
TD.Open query, DB, adOpenKeyset, adLockOptimistic
TD.MoveLast
Dim TestColumnField as string
TestColumnField = TD.Fields("TestColumn") 'This returns the correct value from the database indicating the connection was successful
TD.Fields("TestColumn") = "test"
TD.UpdateBatch (adAffectCurrent) ' This line throws the error
Error that is reported is "Query cannot be updated because it contains no searchable columns to use as a key"
The database is a flat relationship-less database with no keys. I have tried setting "record id" to be a primary key with no luck.
Is this error due to MariaDB not implementing/supporting ADODB recorset? Is it due to my database structure? Or is it simply I am utilising the ADODB recorset incorrectly?
Edit: Here is an example that shows you do not need an SQL update statement. You can simply select the data and call Update.
http://www.accessallinone.com/updating-adding-and-deleting-records-in-a-recordset/
Sub ADODBUpdating()
Dim sql As String
Dim rs As adodb.Recordset
sql = "SELECT * FROM tblTeachers WHERE TeacherID=5"
Set rs = New adodb.Recordset
rs.Open sql, CurrentProject.Connection, adOpenDynamic, adLockOptimistic
'Open RecordSet
With rs
If Not .BOF And Not .EOF Then
.MoveLast
If .Supports(adUpdate) Then
![FirstName] = "x" & ![FirstName]
.Update
End If
End If
.Close
End With
Server side cursor implementation seems to be limited, use client side cursors (DB.CursorLocation = adUseClient) instead.
1.) You can't do an update in SQL with a SELECT-Statement. Instead use the UPDATE-Statement.
2.) Dont't try to update all the records. Only Update the single row you want to update. As you write this should be the last record.
You update the testfield and you have to be sufficiently specific in the WHERE-Clause, that you only select the one and only record record you want to update.
I'm using an Access front-end for an Microsoft SQL back-end.
The problem I'm facing, is that I'm inserting data with an adodb connection. I use this on multiple forms. On the first form it works, on the second form it works, on the third form it also works. But on the fourth form I get an: 'ODBC: Call failed' error.
You might think I made some kind of typing error, but that is not the issue. When I start with form four I can insert the data.
So long story short, after 3 inserts on different form, I get that odbc error. I don't know what the problem is.
Dim Query As String
Dim rs As ADODB.Recordset
Dim cn As ADODB.Connection
Set cn = New ADODB.Connection
Set rs = New ADODB.Recordset
Query = "SELECT MAX(ID) From dbo_Controle"
rs.Open Query, CurrentProject.Connection
rs.MoveFirst
ID = rs.Fields(0).Value
Query = "INSERT INTO dbo_Controle VALUES (" & ID + 1 & ",'" & Me.txtControleTime & "')"
Set cn = CurrentProject.Connection
Debug.Print (Query)
cn.Execute Query
rs.Close
cn.Close
Set rs = Nothing
Set db = Nothing
This is the code I am using on different forms with different queries.
I was having the same issue, and was able to fix it by using CurrentProject.AccessConnection
Access has saved a query that was designed with the query builder called 'myQuery'. The database is connected to the system via ODBC connection. Macros are all enabled.
Excel Has makes a ADODB connection to connect to the database via
Dim con As ADODB.Connection
Dim rs As ADODB.Recordset
Set con = New ADODB.Connection
With con
.Provider = "Microsoft.ACE.OLEDB.12.0"
.Open "MyDatabase.accdb"
End With
Usually you would go ahead and just write your SQL, which is perfectly fine and then just do something like
Dim sqlQuery As String
sqlQuery = "SELECT * FROM myTable"
Set rs = New ADODB.Recordset
rs.Open sqlQuery, con, ...
But I want to access the query that I saved in the access database. So how do I call the saved query in the database that I just connected.
Tried already
con.Execute("EXEC myQuery") but that one told me it could not be find myQuery.
rs.Open "myQuery", con but that one is invalid and wants SELECT/etc statements from it
I think you can treat it like a stored procedure.
If we start right before Dim sqlQuery As String
Dim cmd as new ADODB.Command
cmd.CommandType = adCmdStoredProc
cmd.CommandText = "myQuery"
cmd.ActiveConnection = con
Set rs = cmd.Execute()
Then pickup your recordset work after this.
You were nearly there:
Dim con As ADODB.Connection
Dim rs As ADODB.Recordset
Set con = New ADODB.Connection
With con
.Provider = "Microsoft.ACE.OLEDB.12.0"
.Open "z:\docs\MyDatabase.accdb"
End With
con.Execute "MyQuery"
Just leave out Exec.
You can add parameters, too, this is a little old, but should help: update 2 fields in Access database with Excel data and probably a Macro
I was able to run an update query that was already saved in Access using:
Connection.Execute "My_Update_Query_Already_Saved_In_Access", adExecuteNoRecords, adCmdStoredProc
This gave me errors until I replaced spaces in the query name with underscores in both the Access database and the execute statement.
This is sort of a hack job, but you can query a query. That is, replace your sql string with the following:
sqlQuery = "SELECT * FROM QueryName;"
Before running this, one must ensure that the Access Database has been saved ie. press Ctrl+S (it is not sufficient that the query was run in Access).
Long time since this thread was created. If I understand it correctly, I might have something useful to add. I've given a name to what the OP describes, that being the process of using SQL from a query saved in an ACCDB to run in VBA via DAO or ADOBD. The name I've given it is "Object Property Provider", even with the acronym OPP in my notes, and for the object name prefix/suffix.
The idea is an existing object in an ACCDB (usually a query) provides a property (usually SQL) that you need to use in VBA. I slapped together a function just to suck SQL out of queries for this; see below. Forewarning: sorry, but this is all in DAO, I don't have much use for ADODB. Hope you will still find the ideas useful.
I even went so far as to devise a method of using/inserting replaceable parameters in the SQL that comes from these OPP queries. Then I use VBA.Replace() to do the replacing before I use the SQL in VBA.
The DAO object path to the SQL of a query in an ACCDB is as follows:
mySqlStatement = Access.Application.CurrentDb.QueryDefs("myQueryName").SQL
The way I use replaceable parameters is by evaluating what needs to be replaced, and choosing an unusual name for the paramater that cannot possibly exist in the real database. For the most part, the only replacements I've made are field or table names, or the expressions of WHERE and HAVING clauses. So I name them things like "{ReplaceMe00000001}" and then use the Replace() function to do the work...
sqlText = VBA.Replace(sqlText, "{ReplaceMe00000001}", "SomeActualParameter")
...and then use the sqlText in VBA. Here's a working example:
Public Function MySqlThing()
Dim sqlText as String
Dim myParamater as String
Dim myExpression as String
'Set everything up.
sqlText = getSqlTextFromQuery("myQuery")
myParameter = "{ReplaceMe00000001}"
myExpression = "SomeDateOrSomething12/31/2017"
'Do the replacement.
sqlText = VBA.Replace(sqlText, myParameter, myExpression)
'Then use the SQL.
db.Execute sqlText, dbFailOnError
End Function
Function getSqlTextFromQuery(ByVal oppName As String) As String
Dim app As Access.Application
Dim db As DAO.Database
Dim qdefs As DAO.QueryDefs
Dim qdef As DAO.QueryDef
Dim sqlText As String
Set app = Access.Application
Set db = app.CurrentDb
Set qdefs = db.QueryDefs
Set qdef = qdefs(oppName)
oppGetSqlText = qdef.SQL
End Function