Model Validations
When you edit Xomega models with a Xomega.Net editor, they will be validated for being a well-formed XML, for adhering to the corresponding XSD schemas, and for the specific validation rules that are defined for Xomega models, as described below.
Generally, you will not be able to run any generators on a model that has validation errors. However, you can still run them, if there are only warnings, which will be displayed when you run the generators. You can also configure schema validation severity for different namespaces to allow or disallow running generators for certain types of schema errors and warnings.
Standard XML validations
The standard XML validations are available in Visual Studio for any XML file, even when using a standard XML editor. Xomega.Net editor performs the same validations of Xomega model files for well-formed XML, as well as against the defined XSD schemas that specify the allowed elements and attributes, the order of the elements, and allowed values, where appropriate.
For example, in the main Xomega.xsd schema the types element allows a sequence of either type or type-config elements as its children, but not both. This is done to keep type configs for specific databases, frameworks or technologies in separate files that can be easily included or excluded from the model to add or remove support for specific technologies.
If you add a type-config element to the types element that already has a type element, or vice versa, you will get a schema validation error both in the tooltip of the underlined element and in the Error List window, as illustrated below.

These error messages use standard texts, which at times may not be all that user-friendly. Besides deciphering the real issue from the error text, you can also consult the structure of the underlying XSD or the documentation for the specific elements by pressing F12 on that element or selecting the Go to Definition context menu.
Additional model validations
In addition to standard XML validations, Xomega Editor validates the model against a number of logical rules, which would be hard or impossible to express in the XSD. These rules are designed to keep the model consistent and clean to save developers from costly troubleshooting of model errors in the generated artifacts.
Just like with the standard validations, Xomega Editor will highlight the invalid element, attribute or value, and will show the validation message both as a tooltip and in the Error List window, as follows.

The model validation errors and warnings are typically very detailed and user-friendly, and usually, advise you on how to deal with them. You can also customize the model validation messages or add your own custom validation rules.
Validating the entire model
While Xomega Editor shows validation errors only for the currently open file, you can also validate the entire model to see validation errors and warnings in all model files. To do that you can right-click on the model project and select the Validate option, or pick the Project > Validate menu when the model project is selected.
The validation will happen automatically whenever you run any generators, so this standalone option is useful when you don't want to run any generators.
As you can see from the pictures above, the validation errors and warnings in the Error List window specify the file name and the line number. You can double-click on the error message to open the file and navigate to that line in error.