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copied!<p>NHibernate does have ways to get the database schema, provided it's supported by the database type/dialect. It is primarily used by the SchemaExport and SchemaUpdate functions.</p> <p>If you're not scared of getting your hands a bit dirty;</p> <p>Start by looking at the GenerateSchemaUpdateScript function in the Configuration class: <a href="https://nhibernate.svn.sourceforge.net/svnroot/nhibernate/trunk/nhibernate/src/NHibernate/Cfg/Configuration.cs" rel="nofollow noreferrer">https://nhibernate.svn.sourceforge.net/svnroot/nhibernate/trunk/nhibernate/src/NHibernate/Cfg/Configuration.cs</a></p> <p>In particular, you'd be interested in this class, which is referenced in that method: <a href="https://nhibernate.svn.sourceforge.net/svnroot/nhibernate/trunk/nhibernate/src/NHibernate/Tool/hbm2ddl/DatabaseMetadata.cs" rel="nofollow noreferrer">https://nhibernate.svn.sourceforge.net/svnroot/nhibernate/trunk/nhibernate/src/NHibernate/Tool/hbm2ddl/DatabaseMetadata.cs</a> </p> <p>The DatabaseMetadata object will allow you to traverse the metadata for all tables and fields in the database, allowing you to figure out which fields are not mapped. If you look at the Configuration class again, it holds a list of it's mapping in the TableMappings collection. Taking hints from the GenerateSchemaUpdateScript function, you can compare a Table object from the TableMappings against the any object implementing ITableMetadata returned by the DatabaseMetadata.GetTableMetadata function to figure out which columns are unmapped.</p> <p>Use this information to then rebuild the mapping file used by the "dynamic" class at runtime placing all the dynamic/runtime fields in the "AdditionalProperties" dynamic-component section of the mapping file. The mapping file will need to be included as an external file and not an embedded resource to do this, but this is possible with the Configuration AddFile function. After it is rebuilt, reload the configuration, and finally rebuild the session factory.</p> <p>At this time it looks like Firebird, MsSQL Compact, MsSQL, MySQL, Oracle, SQLite, and SybaseAnywhere have implementations for ITableMetadata, so it's only possible with one of these(unless you make your own implementation).</p>

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