First contact with Oslo

The first presentation about the language Oslo was by Don Box and David Langworty. It was really good to see that I don't have to know T-SQL anymore!

Why "M"

• We want creating and interacting with oslo content to be simple and natural
  • Having a box-and-line design experience is an important enabler
  • Having a complementary textual experience is equally important

• M is how we achieve the latter

What is "M"

• "M" is a language for defining domain models and textual domain-specific languages (DSLs)
• M domain models define schema and query over structured data
  • Values, constraints, and views
  • Natural projection to SQL

• M DSLS define projections from Unicode text to structured data
  • Rule-based transformation
  • Grammar driven text editor integration

What "M" is not

• An object-oriented language
  • No polymorphism, virtual dispatch
  • "ls-a" determined based on structural subtyping, not stipulation

• A data access technology
  • M domain models compile down to T-SQL
  • Tool chain supports course-grained loading/unloading of schemas and values - not an OLTP solution

• A replacement for T-SQL
• Far less expansive feature set
• Tool chain supports linking/invoking T-SQ

So Oslo is an abstraction on T-SQL and although it is not finished yet, it is already fun to play with. A little example:

First to start with a normal table:

Module Contacts

{

People

{

{ Name="persona", Age=29 },

{ Name="personb", Age=28 }

}

}

This actually means that we defined a schema and filled the table with two rows.

Next up constraints:

Module Contacts

{

-- Constraints:

People :

{

Name : Text where value.Count <= 30;

Age : Integer32;

}*;

People

{

{ Name="persona", Age=29 },

{ Name="personb", Age=28 }

}

}

What you see here is a constraint on the People table, which in T-SQL would look like this:

Create table [Contacts].[People]

{

[Age] int not null,

[Name] nvarchar(28) not null

}

It's still another language to learn, but I like this more then T-SQL.