Nice one! Thanks to Paul Galvin for pointing this to the SharePoint community. I am sure there will be few people(including me) writing SQL queries in the BDC definition file as shown in the MSDN documentation. SOME times we ignore to try to take that extra-mile and blindly keep doing in the same way as pointed in the documentation:)

Quote

BDC ADF and your friend, CDATA

I've noticed some awkward and unnecessary hand-encoding of RdbCommandText in some examples (including MSDN documentation).

I wanted to point out to newcomers to BDC that commands can be wrapped inside a CDATA tag in their "natural" form.  So, this awkward construction:

<Property Name="RdbCommandText" Type="System.String">
  SELECT dbo.MCRS_SETTLEMENT.id, dbo.MCRS_SETTLEMENT.settlement from dbo.MCRS_SETTLEMENT 
    WHERE (id &gt;= @MinId) AND (id &lt;= @MaxId)
</Property>

can be better represented this way:

<Property Name="RdbCommandText" Type="System.String">
  <![CDATA[
    SELECT dbo.MCRS_SETTLEMENT.id, dbo.MCRS_SETTLEMENT.settlement from dbo.MCRS_SETTLEMENT
      WHERE (id >= @MinId) AND (id <= @MaxId)
  ]]>
</Property>

</end>

BDC Primer

Intro to BDC

I just noticed that Microsoft has announced BDC Metadata Editor. This is cool! It will save a lot of time when it comes

to creating BDC application definition. I like the part that it creates Associations when foreign key are selected.

Highlights

• Tool supports databases (SQL, Oracle, OLEDB, and ODBC) and web services
• Drag and drop design surface for selecting DB tables or web methods:
• Metadata is automatically extracted from databases by dragging and dropping tables
• Web Services require a few additional steps to completely configure the connection
• Users can import and export Application Definition XML files
• Users are able to test method instances incrementally from within the tool
• The tool is not required to run on a web front-end
• Associations are created automatically when foreign keys are selected; they can also be created easily for web services by adding an Association method instance

For more details click here 

-Guru