Thursday, 21 February 2008

Using TSQL Queries for AD Authentication

Yes you can directly query AD using TSQL queries. And it's REALLY easy.

Why you ask – well, LDAP can be painfully slow if you have to trawl through groups eg if you are storing the results in a table or outputting them to screen or suchlike. I've found this method to be pretty reliable and reasonable with regards to performance.

First things first… on a SQL server, you need to create a linked server to AD as follows:

EXEC master.dbo.sp_addlinkedserver @server = N'ADSI', @srvproduct=N'Active Directory Service Interfaces', @provider=N'ADSDSOObject', @datasrc=N'adsdatasource'
EXEC master.dbo.sp_serveroption @server=N'ADSI', @optname=N'collation compatible', @optvalue=N'false'
EXEC master.dbo.sp_serveroption @server=N'ADSI', @optname=N'data access', @optvalue=N'true'
EXEC master.dbo.sp_serveroption @server=N'ADSI', @optname=N'dist', @optvalue=N'false'
EXEC master.dbo.sp_serveroption @server=N'ADSI', @optname=N'pub', @optvalue=N'false'
EXEC master.dbo.sp_serveroption @server=N'ADSI', @optname=N'rpc', @optvalue=N'false'
EXEC master.dbo.sp_serveroption @server=N'ADSI', @optname=N'rpc out', @optvalue=N'false'
EXEC master.dbo.sp_serveroption @server=N'ADSI', @optname=N'sub', @optvalue=N'false'
EXEC master.dbo.sp_serveroption @server=N'ADSI', @optname=N'connect timeout', @optvalue=N'0'
EXEC master.dbo.sp_serveroption @server=N'ADSI', @optname=N'collation name', @optvalue=null
EXEC master.dbo.sp_serveroption @server=N'ADSI', @optname=N'lazy schema validation', @optvalue=N'false'
EXEC master.dbo.sp_serveroption @server=N'ADSI', @optname=N'query timeout', @optvalue=N'0'
EXEC master.dbo.sp_serveroption @server=N'ADSI', @optname=N'use remote collation', @optvalue=N'true'

That's all the configuration you have to do. You are good to go!

Below is an example of the TSQL syntax.

Note that the DC is the domain in which the AD resides – in this instance it has three parts MyDomainName,DC=MyTopLevelDomain,DC=MyDomainCountryCode eg DC=microsoft,DC=com,DC=au. In this example, I am returning the username of all users who are a member of the AD group called GAMyADGroupName. This example checks if a particular user is a member of a particular AD group:

'SELECT sAMAccountName
FROM ''LDAP://DC=csr,DC=com,DC=au''
WHERE objectCategory = ''Person''
AND objectClass = ''user''
AND memberOf = ''CN=GAMyADGroupName,OU=Other,OU=Global Groups,OU=Security Groups,DC=MyDomainName,DC=com,DC=au''
AND sAMAccountName = ''MyUserName''')

Monday, 18 February 2008

SSIS Synchronous/Asynchronous Script Transformations in a Data Flow

Asynchronous just means it consumes all rows before progressing to the next step in the data flow – unlike most other transformations where the entire data flow is executed for each row before the next row is commenced. Script transformations can be synchronous (eg Lookup) or asynchronous (eg Sort or Aggregate).

A synchronous script transformation is identified because the output is linked to a specified input. This is done in the Inputs and Outputs area of the task by entering the ID from the Input properties in the SynchronousInputID field of the Output properties. For each row of input, there will be one row of output.

An asynchronous script transformation is identified firstly because the SynchronousInputID field of the Output properties contains "None" or "0". When a new row is to be added, it is explicitly done using:


In order to aggregate data, flatten rows or concatenate data from different rows, you simply set a flag to identify when a new row should be added. To do this you need to declare a boolean in the class but outside the main sub:

Public Class ScriptMain

Inherits UserComponent

Private blnFirstRow As Boolean = True
Dim opMessage1 As String = ""

Public Overrides
Sub Input0_ProcessInputRow(ByVal Row As Input0Buffer)

In this example, I'm taking all rows and flattenning them into one row so the first step in my sub is:

If blnFirstRow = True Then Output0Buffer.AddRow()
blnFirstRow = False
opMessage1 = opMessage1 & " " & Row.ipMessage.ToString

Note that I then concatenate a variable with a new value… Alternately, you could set a flag so that a new row is added when certain conditions are met such as the value of the ipCustomerNo changes.

One other thing to add - you need to use the PostExecute() sub to write to variables.