title: Liquibase Data Type Mapping documentation
body: <p>Sorry, this question seems stupid, but I tried 1 hour searching and didn't find anything.
  So I'm using liquibase for multiple databases(e.g. MSSQL, Oracle and MySQL), when I say:</p>
  
  <pre><code>addColumn(tableName: "ABC_TEST") {
    column(name: "IS_ACTIVE", type: "boolean")
  } 
  </code></pre>
  
  <p>How do I know if the type "boolean" will be converted to proper types for each database?
  And is there any documentation I can find for the data type mapping? If I want to add one more column which is foreign key, which type should I use?</p>