I am developing an application in C# VS 2010 past 4 months. I used MS Access 2007 to store my nearly 20 tables successfully.
Today I realized that my data base cannot be handled consistently by MS Access 2007. Hence I decided to go for SQL Server 2008 R2 Express with Upsizing wizard and it worked really great!
However, when I tried to run various options of my already well developed application, It kept throwing error each time when a query is fired to SQL Server.
I understood that Many of the stuffs of SQL supported by MS Access are not supported by MS SQL Server
For example: query with date, for representing date format when we use '#', SQL Server 2008 won' t recognize it.
Also, for Bool value, MS Access stores it as True and False where as SQL Server uses 0.
These all queries worked perfect with Access 07
I am sure that there must be some method so that SQL Server can understand MS access queries.
Or will I have to edit my whole application?? It will be as good as digging a mine for earning gold..
I have changed all data access objects such as reader, adapter, command, connection to SQL data objects using System.Data.SqlClient.
So, It is not the problem.
Please help me asap.
Thank you.
You cannot force SQL Server to run the MS Access queries. These queries will need to be rewritten to use T-SQL instead of the query language that MS Access uses.
I feel your pain, I just had to rewrite a large MS Access application (over 1k queries) that needed to be recreated to be used in SQL Server.
There will be some queries that might be able to be ported over directly but as you noticed queries with date, and even some of the aggregate functions (First(), etc) are not used in SQL Server and those queries will need to be changed.
Here is a link with some info on converting Access to SQL
Converting Access Queries to SQL Server
You are right that, most of the time, you cannot just take the SQL of a query from Access and run it within SQL Server. It may work for very simple queries, but usually you need to tweak them.
There are a few steps I would take:
Extract your queries (which I presume are in your code), and re-create them in your Access database. Make sure they work there as normal Access queries.
(you can for instance simply add some code to your app to print all queries to files so you don't have to mess with parameters, then just copy/paste them in your Access DB).
The point is simply to have working queries within Access.
Use SSMA from Microsoft for helping you to move your queries to SQL Server. It does a good job of translating them into T-SQL.
You may still have to convert some troublesome queries by hand, but it shouldn't be that many and usually the conversion is not difficult.
Once converted to T-SQL, just re-inject these working queries into your code, or keep the complex queries in SQL Server as views (which it usually be faster as SQL Server will have already created its execution plan, rather than your application sending raw SQL that the server needs to analyse).
As you pointed out, there could be some issues if your fields use some features that don't cross-over to SQL Server properly.
Look at your tables in Access and do some cleanup before attempting to convert:
For booleans fields:
Make sure you set their default values to 0 or 1 (they should not be empty).
Required fields must be non-null:
Make sure that any fields that you have set as 'Required' does not contain any NULL values in its data.
Unique indexes cannot ignore Null:
Check that your indexes are not set to be both 'Unique' and 'Ignore null'.
All tables must have clean primary keys:
Make sure all your tables have a unique primary key that doesn't have Null values in their data.
Related
I have an MS Access application with data in a separate access mdb. We need to move the data to MS SQL. Previously when I did this is worked very well - dramatic speed improvements. In this new upgrade however, we are seeing some problems with translating of the SQL from Access to SQL.
We have the solution separated into an APP mdb and a DATA MDB. We use Linked-tables to join the two. After migrating the data to SQL server, we created an ODBC link, then re-pointed the linked-tables to the SQL data source over ODBC. We would expect the SQL command generated by Access, to be simply transferred to SQL server, for SQL server to operate on same using its normal efficiency and power.
When I put a trace on SQL Profiler, instead of seeing for example a simple "Delete * from table", we see a series of delete statements, one for each record in the table ...
We see the same thing for updates - where we would expect for example "insert into table1 (select a,b,c from table2)...) to be sent as an SQL string, to be executed on the server, we instead see a series of insert statements, one per row being inserted, being sent to the server.
It seems that Access is trying to work out the logic for everything but select statements client side and not letting MS SQL server take care of things as one would expect.
Anyone experienced this behaviour before and can offer a suggestion to resolve?
thanks.
I have an access 2003 database that holds all of my business data. This access database gets updated every few hours during the day.
We're currently writing a website that will need to use the data from the access database. This website (for the time being) will have only read only capabilities. Meaning there will only need to be one way transfer of data (Access -> SQL).
I'm imaging there's a way to perform this data migration from access to SQL server programatically. Does anyone have any links to something I can read about?
If this practice sounds odd, and you'd like to suggest another way to do this (or a situation where data can go both ways (Access -> SQL, SQL -> Access), that's perfectly fine.
The company is going to continue using Access 2003 for their business functionality. There's no way around that. But I'd like to build the (readonly) website on top of SQL Server.
The strategy you outlined can be very challenging. You could use INSERT queries to copy new Access rows to SQL Server, as described in another answer.
However, if you have changes to existing Access rows, and you also want those changes propagated to SQL Server, it won't be so simple. And it will be more complicated still if you want deleted Access rows deleted from SQL Server, too.
It seems more reasonable to me to use a different approach. Migrate the data to SQL Server once. Then replace the tables in your Access database with ODBC links to the SQL Server tables. Thereafter, changes to the data from within your Access application will not require a separate synchronization step ... they will already be in SQL Server. And you won't need to write any code to synchronize them.
If your concern is that the connections between the web server and SQL Server be read-only, just set them up that way. You can still independently allow read-write permissions for your Access application.
To do the initial data migration and set the SQL Server automatically, I would use the SQL Server Migration Assistant. The only thing you should definitely change that I can think of would be to turn off the Identity property on any columns that have it - to be explained below (MS Access calls Identity autonumber). Once you have your tables loaded, you can set up a dsnless connection to the database (and tables) you just created.
I haven't used the method just linked, but I believe it allows you to use SQL Server authentication to connect to the db. The benefit of using this method is you can easily change which SQL Server instance and/or database your are connecting to for development and testing.
There might be a better, automated way, but you can create several insert queries doing left joins from the primary key of the Access table to the SQL Server table, and putting a WHERE clause that specifies the SQL Server PrimaryKey must be null. This is why you need to turn off the Identity property in the SQL Server tables, so that you can insert the new data.
Finally, put the name of each query in one function, then run the function periodically.
I have used Microsoft's free SQL Server Migration Assistant (SSMA) to migrate Access to SQL Server. The tool is very simple to use. The only problem I have encountered with the tool was overloaded data types when migrating. What I mean by this is a small string will get converted to a NVARCHAR(MAX) in some instances. Otherwise, the tool is very handy and can be reused after setting up a 'profile'.
I need to transfer certain information out of our SQL Server database into an MS Access database. I've already got the access table structure setup. I'm looking for a pure sql solution; something I could run straight from ssms and not have to code anything in c# or vb.
I know this is possible if I were to setup an odbc datasource first. I'm wondering if this is possible to do without the odbc datasource?
If you want a 'pure' SQL solution, my proposal would be to connect from your SQL server to your Access database making use of OPENDATASOURCE.
You can then write your INSERT instructions using T-SQL. It will look like:
INSERT INTO OPENDATASOURCE('Microsoft.Jet.OLEDB.4.0','Data Source=myDatabaseName.mdb')...[myTableName] (insert instructions here)
The complexity of your INSERTs will depend on the differences between SQL and ACCESS databases. If tables and fields have the same names, it will be very easy. If models are different, you might have to build specific queries in order to 'shape' your data, before being able to insert it into your MS-Access tables and fields. But even if it gets complex, it can be treated through 'pure SQL'.
Consider setting up your Access db as a linked server in SQL Server. I found instructions and posted them in an answer to another SO question. I haven't tried them myself, so don't know what challenges you may encounter.
But if you can link the Access db, I think you may then be able to execute an insert statement from within SQL Server to add your selected SQL Server data to the Access table.
Here's a nice solution for ur question
http://www.codeproject.com/Articles/13128/Exporting-Data-from-SQL-to-Access-in-Mdb-File
I have tried to look at sys.dm_db_missing_index_details to check for missing indexes on my SQL Server 2005 database. It is returning no rows.
It is possible that it should be empty but highly unlikely as I have not added ANY indices on any table (except the ones you get by creating primary keys). I am also running unit tests as well as adhoc development tests (using Linq to SQL) against it so there is some activity against it.
Do I need to turn on the capturing of this data?
Is this only supported on certain editions of SQL Server 2005?
Thanks in advance for any efforts to help.
It appears that it's on by default - although check any shortcut you are using to launch and make sure it's not launching with a -x
From http://msdn.microsoft.com/en-us/library/ms345524(v=SQL.90).aspx
This feature can only be disabled if an instance of SQL Server is started by using the -x argument with the sqlservr command-prompt utility.
Also you'll want to know that the table is populated as queries are run if SQL Server uses the query optimizer - this table is cleared when you restart SQL Server.
From http://msdn.microsoft.com/en-us/library/ms345434(v=SQL.90).aspx
Information returned by sys.dm_db_missing_index_details is updated when a query is optimized by the query optimizer, and is not persisted. Missing index information is kept only until SQL Server is restarted. Database administrators should periodically make backup copies of the missing index information if they want to keep it after server recycling.
Lastly there is an article that goes into the limitations here that you may or may not know about, but I'll post in case someone else happens across this post and needs: http://msdn.microsoft.com/en-us/library/ms345485(v=SQL.90).aspx
I didn't see anything about the feature being missing in some versions but you WILL need certain permissions:
Users must be granted the VIEW SERVER STATE permission or any permission that implies the VIEW SERVER STATE permission to query this dynamic management view.
Another option is to query the plan cache directly -- this also has the benefit that it can get you the query that wants the index. There's a related question here on SO -- the answer from BankZ has a complete SQL script that does the job.
It may run slowly though - the plans are in XML format, so with this query, we're asking SQL Server to do lots of XML work rather than table work. But it does work :-)
And as with the main missing index table, the plan cache is cleared down if SQL Server is restarted.
I'm using DTS to import data from an Access database to SQL Server 2005. It seems that DTS imports Access queries as tables instead of views, which won't work for me. Is there any way around that?
You can choose to not include the saved queries. (at least you can when using the SSMA - I suggest you use this in place of DTS anyway…it tends to do a better job).
you can find it here:
http://www.microsoft.com/sqlserver/2005/en/us/migration.aspx
It is not clear if you going to continue to use ms-access as the front end here or not?. If you plan to continue using access then you really don’t need to convert those saved queries (views) up to sql server anyway. Most of the saved queries in access will work as before (now with linked tables to sql server).
You only need change/fix those saved quires that run slow. In other words most queries can continue to be used and run as is. It is only the slow ones and especially the ones with aggregate functions (sums, totals etc that process many records, but produce few rows). This types of queries really benefit from being moved up to sql server as a view (you then link to that view from ms-access).
If your not keeping any part of ms-access, then I am afraid there no automated tool for those queries. In these cases I just do a cut + paste from ms-access right into the management studio view builder. Most queries require very little modifications.