Yes, defining an account schema is an essential step when implementing a JDBC connector. The schema defines the structure of the identity data being pulled from the database, including the attributes that will be mapped to identity profiles in IdentityNow. The schema can be defined either by using the "Discover Schema" option, which automatically identifies available attributes, or by manually configuring the schema attributes if specific custom mappings are required.
References:
SailPoint IdentityNow JDBC Connector Schema Configuration Guide.
SailPoint IdentityNow Source Schema Discovery Documentation.