title: Insertable UNION ALL VIEW on SQL Server 2012
body: <p>I have this schema provided and unmodifiable:</p>
  
  <pre><code>Table: Company1 Customers
  +-------------+---------------+
  | Customer ID | Customer Name |
  +-------------+---------------+
  | C0001       | ACME Inc.     |
  | C0002       | Bogus Corp.   |
  +-------------+---------------+
  
  Table: Company2 Customers
  +-------------+---------------+
  | Customer ID | Customer Name |
  +-------------+---------------+
  | C0001       | Foo Bar Ltd.  |
  | C0002       | John Smith    |
  +-------------+---------------+
  </code></pre>
  
  <p>I need a insertable/updateable/deleteable view like this:</p>
  
  <pre><code>View: All Customers
  +----------+-------------+---------------+
  | Company  | Customer ID | Customer Name |
  +----------+-------------+---------------+
  | Company1 | C0001       | ACME Inc.     |
  | Company1 | C0002       | Bogus Corp.   |
  | Company2 | C0001       | Foo Bar Ltd.  |
  | Company2 | C0002       | John Smith    |
  +----------+-------------+---------------+
  </code></pre>
  
  <p>and I built it as:</p>
  
  <pre><code>CREATE VIEW [All Customers] AS
     SELECT 'Company1' AS [Company], [Customer ID], [Customer Name]
     FROM [Company1_Customers]
  UNION ALL
     SELECT 'Company2' AS [Company], [Customer ID], [Customer Name]
     FROM [Company2_Customers]
  </code></pre>
  
  <p>How (if possible) can I tell SQL Server that all INSERT/UPDATE/DELETE operations in this view where <code>[Company] = 'Company1'</code> belong to <code>Company1_Customers</code> and where <code>[Company] = 'Company2'</code> belong to <code>Company2_Customers</code>?</p>