I am in the process of writing a reporting service that will be used across our whole company. The problem I have is there is not one central database all the reports will run of, each division has its own separate one. Lucky the database schema’s are consistent, but I needed a way of:

a) setting the report data source at run time and
b) letting the users control the database they want to connect to. Some high level user need to be able to access multiple databases, while others will just need access to their local one

So, here’s how I went about doing it.

Setting Data source at Run time

Normally, when you setup a reports data source in reporting services, you just point it to the database you want it to use (probably using a shared data source) give it some credentials and off you go. You would probably end up with a connection string looking something like this:

Under normal circumstances that would work fine. But not this time. I need an easy way to replace the information held in the connection string with some sort of variable.

Turns out the easiest way to do it is by using a parameter in the connection string. You can create the connection string as an expression as if you were working with any other part of the report. However, before doing this you first need to create the parameters and fill them with some data.

Data Source Table

In the reports database, I created two new tables, one that will hold the name of the reports servers, database names and Active directory group with access to this data source. The other one will contain all the user names and what Database they are currently using. Download the SQL scrip to create the databases below

hello

Run this script on your reports sever database, and you will have two new tables, database_details and user_details. In order to do the tests you will need to create an entry in the database table (database_details) for your database, and an entry in the user table (user_details) for your username (include the domain name so it should read dom\joe.bloggs) and point it using the site_id filed to the database. You are now ready to create the SQL in the report that will populate the parameters

Dataset Containing the database connection details

Create yourself a test report, and in that report create a new dataset that points at your reports server database. The SQL needs to be the following:

SELECT     jp_user_details.username, jp_database_details.server_name, jp_database_details.database_name
FROM         jp_user_details INNER JOIN
jp_database_details ON jp_user_details.site_id = jp_database_details.site_id

This will return all the names in your database, what we need to do now is make sure at run time it only returns data for the user running the report. To do that we need to put a filter on the report. The filter will be:

Fields!username.value=User!UserID

and should look like this in your Dataset properties

The Parameters

Once you have done this dataset, you need to create a couple of parameters. One will be for the server name, one for the database name. So go into your report parameters and create the following, with these options:

Name - ServerName
Datatype - String
Hidden - Yes
Available Values from Query: Select your dataset , then both values fields need to be server_name
Default Values From Query - Select your dataset, value field is server_name

Name - DatabaseName
Datatype - String
Hidden - Yes
Available Values from Query: Select your dataset , then both values fields need to be database_name
Default Values From Query - Select your dataset, value field is database_name

What does this do? Well, when you run your report now you will have the two parameters you have just created filled in with the server name and database name the person running the report wants to report on. The parameters are set to hidden so the user knows nothing about them.

Final Step, create your dynamic dataset

Now we have everything we need in place, the last step is to create a dataset that will look into the server held agaist the user, and retrive us the actul information we want. Create a new dataset, and in the connection string of this data source put the following:

= “data source=” & Parameters!ServerName.Value & “;initial catalog=” &  Parameters!DatabaseName.Value

It should look like this in the window

Now when you run the report, you data source will be based on the users choice held in the table

A couple of things to note

You will find it hard (probably impossable) to write the report with the parameterized data source. You’ll need to work with your local copy of the database hardcodded into the connection string first, then when you are happy with it change it to the parameter driven one. If you dont do this the report designer wont be able to read the dataset.

You also need to be carful the order in witch you put your user paramters on the report. I found that if i did’nt put data driven parameters (ie a list of sales areas the user can select) at the top of the list, they were greyed out when you tried to run the report. Not sure why, but i asume its down the the order the datasets are exceuted in

If you have any problems with this, or have any different ways of doing it let me know!