以下 WSO2 DSS 错误代码的解释是什么

What are the explanations for below WSO2 DSS error codes

我想了解以下从 WSO2 DSS 抛出的错误代码的解释。

DATABASE_ERROR
CONNECTION_UNAVAILABLE_ERROR
VALIDATION_ERROR
INCOMPATIBLE_PARAMETERS_ERROR
UNKNOWN_ERROR
DATABASE_ERROR - Database errors occurring such as SQLExceptions when creating a query in the data service level
CONNECTION_UNAVAILABLE_ERROR - Erors occurring while initializing connections in JNDI datasources 
VALIDATION_ERROR - Errors occurring when using validators, essentially when a validation fails 
INCOMPATIBLE_PARAMETERS_ERROR - Errors occurring while converting a query's ExternalParams to parameters by making necessary transformation as instructed by with-param elements
UNKNOWN_ERROR - Any error does not fall into the above categories