I have a project that will be using Access 2003 as the front-end and the data will be stored in SQL Server. Access will connect to SQL Server via linked tables with all the database logic (stored procedures, views) within SQL Server.
Given this setup, would it be better to use ADO or DAO within Access? Is it just a matter of preference or is one more suited to Access as a front-end and SQL Server as the data store? Especially when using linked tables. Thanks.
Write pass-thru queries as opposed to the linked table approach. Performance will be greatly improved. Writing an Access app?
Create some local tables to store some query results. You can dynamically change the pass-thru queries as needed as well as connection info for connecting to multiple databases.
Edit: General consensus is ADO for connecting to sql server/other sources and DAO for mdb only sources.
Use an MDB with ODBC linked tables. Because you are using ODBC, you are connecting via Jet, so it's obvious that DAO is the default choice for data access.
ADO should be used only for those things that can't be done otherwise, or that are performing poorly.
In short, you build your SQL Server app just like you would a pure-Access app (assuming you build an app with a Jet/ACE back end to retrieve data efficiently, which should be a no-brainer), and only resort to server-side functionality or ADO when the default Access approach is inefficient or doesn't get the result you need (e.g., an editable recordset in the case of recordset-returning sprocs).
DAO was used to access MDB databases from any COM application. I don't believe it can even connect to SQL Server.
ADO is a successor of DAO. ADO can connect to many databases, but interacts especially well with SQL Server. So in your situation, using ADO seems like a no brainer.
Related
I am having to develop an application very rapidly. I have chosen SQL Server (2012) as the DB backend, and I will write all my stored procs, triggers etc in the backend.
However, for UI (logon, reporting etc), I am using Access 2010 for the frontend. I am new to both Access used earlier versions of Access waaay back in the day) and SQL Server (familiar with other Db's).
The goal is to have the database reside on a server and let clients connect with an instance of Access 2010 running locally on their machine.
I am looking for a quick tutorial that shows me how to use the SQL server objects from the Access frontend (I believe its called linking) - any link to useful resource would be very helpful, as I can't seem to locate anything useful (I may searching using the wrong keywords).
Assuming you built all the tables and data on SQL server, then in Access it is a simple matter to link Access to that database.
And to save development time, you can continue to use the Access simple approach of using forms bound to those tables. As long as you launch a form with some kind of criteria (say an invoice number), then that bound form will ONLY pull down the one record from SQL server into that form. (so need to write or use store procedures etc. for that form). And any triggers etc. you have built in SQL server will run without you having to do anything from the Access side.
So a plane jane form build in Access that is bound to a table of say 1 million rows in Access does not need any “special” code – just make sure you launch the form with the “where” clause that Access provides and the form will only pull + load the one record.
So 99% of the normal development process you used in Access in the past will continue to work. Using SQL server for the most part does not change much if anything in regards to building forms that edit such data.
However, for reports and some forms that query + search for data etc., or some VBA code that needs to “process” data, you are most free to call store procedures. You simply create a pass-through query in Access. The VBA code to use that T-SQL thus looks like this:
Currentdb.QueryDefs("MyRawt-sqlPassThoughquery").Execute
Or
with CurrentDb.QueryDefs("MyPass")
.SQL = "exec sp_myProc"
.Execute
end with
In the past for most access applications you likely used liked tables – those linked tables can be to a Access file (back end), or Oracle, or SQL server – how the actual application works and functions is really much the same for all cases. (so there not really a lot of “specific” things you need to know from the Access side – if you comfortable with Oracle, or SQL server, then using Access as a front end works just fine, and the typical development approaches used in Access will remain typical.
Here is an article that outlines the linking process:
https://support.office.com/en-us/article/Import-or-link-to-SQL-Server-data-A5A3B4EB-57B9-45A0-B732-77BC6089B84E?ui=en-US&rs=en-US&ad=US&fromAR=1
Keep in mind you will see MANY articles that talk about ADP projects - they have been deprecated since Access 2010, and I don't recommend using ADP projects with Access - so be careful, since many articles that talk about Access + SQL server are built around ADP projects which as noted should not be used anymore.
This office.microsoft.com article should give you a good overview.
With plenty of more technical information searching for "query sql server from ms access".
Don't mess about with linked tables. Use an Access ADP (Access data project), which is natively connected to SQL Server. Sadly this type of access file is being phased out but it is the optimal solution for an MS Access front end with a SQL Server back end
Pros and Cons of Access Data Project (MS Access front end with SQL Server Backend)
Is there seriously no way of using a shared access non-server driven database file format without having to use an SQL Server? The Entity Framework is great, and it's not until I've completely finished designing my database model, getting SQL Server Compact Edition 4.0 to work with Visual Studio that I find out that it basically cannot be run off a network drive and be used by multiple users. I appreciate I should have done some research!
The only other way as far as I can tell is to have to set up an SQL server, something which I doubt I would be able to do. I'm searching for possible ways to use it with Access databases (which can be shared on a network drive) but this seems either difficult or impossible.
Would I have to go back to typed DataSets or even manually coding the SQL code?
Another alternative is to try using SQL
Install SQL Server express. Access is not supported by EF at all and my experience with file based databases (Access, SQL Server CE) is mostly:
If you need some very small mostly readonly data to persist in database you can use them (good for code tables but in the same time such data can be simply stored in XML).
If you expect some concurrent traffic and often writing into DB + larger data sets their performance and usability drops quickly. They are mostly useful for local storage for single user.
I'm not sure how this relates for example to SQLite. To generate database from model for SQLite you need special T4 template (using correct SQL syntax).
Have you tried SQLite? It has a SQL provider, and as far as I know EF supports any provider. Since it's file-based, that might be a plausible solution. It's also free.
What strategies and techniques have you used to produce a data driven application that needs to access multiple diverse data sources? Specifically, Microsoft Access and SQL Server. Ideally, I'd like to make an abstraction layer that hides the physical data source from the application.
Something like the ADO.NET Entity Framework would be ideal, but it doesn't have an MS Access provider. Is there a different framework or technique that supports simultaneous Access and SQL Server connections?
How much work would it be to make an Access provider for the Entity Framework?
I'm pretty sure LLBLGen supports Access (and, of course, it supports MS SQL). It costs money though, but IMHO it's the best OR/M for .NET.
Another approach is to create Linked Servers in SQL Server, perform joins using views in SQL Server and completely hide the fact there are multiple data sources from your application.
As far as I know, there are only two choices:
Multiple connection strings
Single connection string.
In the first scenario, you join any data you need from the disparate sources in the middle tier code. In the second scenario, you access all sources but one indirectly through the one source. For example, you'd retrieve data from Access via a Linked Server in SQL Server.
They each have their advantages and disadvantages. Using a single connection string is certainly simpler to code against in the middle-tier. Ultimately it depends on the need of two sources. If one is simply for logging for example, then two connection strings might be simpler. If joins and such are needed, then using a linked server might be easier depending on the sources. If one of the sources is Access and you are not using Access security, then using a Linked Server can work fine depending scale. If you are using Access security and have different logins that need to access the database, then using a linked server will be a pain.
Look at NHibernate. It has providers for SQL Server and Access (and others).
Microsoft Access is a slick way to access data in a MS SQL Server backend database, but I've always had problems accessing (so to speak) large tables of data, especially when trying to toggle between results and design mode in Access.
Access gives me a number of nifty things, not the least of which is Crosstabs, but this hung connection to the server drives me a little crazy!
Does any MS Access gurus know how to optimize the ODBC connection so it isn't doing what appears to be full table scans when I just want to tweak and build my queries?
The ODBC driver will pass as much work as possible to SQL Server but as soon as you use a vba function like Nz or non-SQL Server syntax like PIVOT then the ODBC driver must pull back more data and indexes to get the work done on the client side.
As per other answer either build your views in SQL Server and link to the views or else use an Access Data Project.
NB: PIVOT queries with unknown number of columns cannot be handled in SQL Server in the same way that Access will do this natively - so if you run a pivot in Access against SQL Server data you will likely pull the whole table back. Pivot queries must be built in SQL Server using dynamic SQL techniques or else pre-saved views that have all the columns hard coded. Check out this link for one way to do this:
http://www.sqlservercentral.com/articles/Advanced+Querying/pivottableformicrosoftsqlserver/2434/
As others have said, the only way to improve performance on large tables is to have the SQL Server database engine do the work for you. A method of doing this which hasn't been mentioned is to use a pass-through query, which will enable you to keep all your code in MS Access, without having to create objects on the SQL Server:
http://support.microsoft.com/kb/303968
You will have to write SQL Server T-SQL rather than the Access dialect; however, SQL 2005 (when running in compatibility mode 90) does support a PIVOT command.
My similar problem was that the ORACLE ODBC connection hung after selecting the Link table/ODBC connection. Task manager said not responding after 10's of minutes. The connection then pings ORACLE for all available tables. I had turned on logging on the ORACLE ODBC Administrator, so it had to write all these things to the log, slowing any results by perhaps hours. The log was 60 MB one hour later, when I turned it off, then everything was fine!
To turn it off go to the Oracle installation/Network Administration/MS ODBC Adminstrator/Tracing tab and turn it OFF!
A good resource on ODBC is here: http://eis.bris.ac.uk/~ccmjs/odbc_section.html
Unfortunately Access is not able to push a lot of that work to the server, and yes, it will do huge table scans when designing queries against multiple tables or views in SQL Server.
You can build and tweak queries (views) in SQL Server using SSMS and store the views in SQL Server for a massive performance boost and still use Access for your front end.
This should be simple. I'm trying to import data from Access into SQL Server. I don't have direct access to the SQL Server database - it's on GoDaddy and they only allow web access. So I can't use the Management Studio tools, or other third-party Access upsizing programs that require remote access to the database.
I wrote a query on the Access database and I'm trying to loop through and insert each record into the corresponding SQL Server table. But it keeps erroring out. I'm fairly certain it's because of the HTML and God knows what other weird characters are in one of the Access text fields. I tried using CFQUERYPARAM but that doesn't seem to help either.
Any ideas would be helpful. Thanks.
Try using the GoDaddy SQL backup/restore tool to get a local copy of the database. At that point, use the SQL Server DTS tool to import the data. It's an easy to use, drag-and-drop graphical interface.
What error(s) get(s) thrown? What odd characters are you using? Are you referring to HTML markup, or extended (eg UTF-8) characters?
If possible, turn on Robust Error Reporting.
If the problem is the page timing out, you can either increase the timeout using the Admin, using the cfsetting tag, or rewrite your script to run a certain number of lines, and then forward to itself at the next start point.
You should be able to execute saved DTS packages in MS SQL Server from the application server's command line. Since this is the case, you can use <cfexecute> to issue a request to DTSRUNNUI.EXE. (See example) This is of course assuming you are on a server where the command is available.
It's never advisable to loop through records when a SQL Update can be used.
It's not clear from your question what database interface layer you are using, but it is possible with the right interfaces to insert data from a source outside a database if the interface being used supports both types of databases. This can be done in the FROM clause of your SQL statement by specifying not just the table name, but the connect string for the database. Assuming that your web host has ODBC drivers for Jet data (you're not actually using Access, which is the app development part -- you're only using the Jet database engine), the connect string should be sufficient.
EDIT: If you use the Jet database engine to do this, you should be able to specify the source table something like this (where tblSQLServer is a table in your Jet MDB that is linked via ODBC to your SQL Server):
INSERT INTO tblSQLServer (ID, OtherField )
SELECT ID, OtherField
FROM [c:\MyDBs\Access.mdb].tblSQLServer
The key point is that you are leveraging the Jet db engine here to do all the heavy lifting for you.