Taming the Jungle: 2007年7月

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7月12日

Down with CAML

CAML as used in Microsoft SharePoint is a “XML-based” query/update language. It’s my pet example of XML abuse. Or “just because you can do something it doesn’t mean you should”.

When compared to the SQL, CAML looses big time:

CAML is not a standard, you need to learn it
CAML is way harder to learn and use than SQL
CAML is very complex
I can’t see what day to-day stuff you can do in CAML and can’t do in SQL (there may exist some arcane example as the exception that proves the rule)
CAML is a “lower-level” abstraction than SQL. You have to build a three very similar to the one a compiler would after reading your SQL code.

After having to use it to write queries as part of a Sharepoint project, I toyed with the idea of writing a “SQL where-clause” to CAML converter. So I could write a simple, SQL-like WHERE clause and it would generate the corresponding CAML expression. Well, I didn’t need to. My fellow MVP, Carlos Segura Sanz did just that:

http://www.ideseg.com/SharePointYetAnotherCAMLQueryToolAlaSQL.aspx

So instead of writing this:

<Query> <Where> <Or> <And> <Eq> <FieldRef Name="Column1" /> <Value Type="Text">Value1</Value> </Eq> <Eq> <FieldRef Name="Column2" /> <Value Type="Text">Value2</Value> </Eq> </And> <And> <Eq> <FieldRef Name="Column3" /> <Value Type="Integer">10</Value> </Eq> <IsNotNull> <FieldRef Name="Column3" /> </IsNotNull> </And> </Or> </Where> <GroupBy> <FieldRef Name="Column1" /> </GroupBy> <OrderBy> <FieldRef Name="Column1" /> <FieldRef Name="Column2" Ascending="True" /> <FieldRef Name="Column3" Ascending="False" /> </OrderBy></Query>

You just write this:

WHERE ((Column1 = "Value1") AND (Column2 = "Value2")) OR ((Column3 = 10)
AND (Column3 <> NULL)) GROUPBY Column1 ORDERBY Column1, Column2 ASC, Column3 DESC

He even has a DLL you can use in your projects to do this at runtime!

Thanks, Carlos.

日志

Down with CAML