Methods, systems, apparatuses, and computer program products are provided for secure handling of queries by a data server and a database application. A parameterized query is received from a client. Table column metadata is loaded for one or more table columns referenced by the parameterized query. Datatypes of expressions in the parameterized query are derived with any parameters and variables of the parameterized query indicated as having unknown datatypes. Unsupported datatype conversions in the parameterized query are determined. An encryption scheme is inferred for any parameters and variables to generate an inferred encryption scheme set. The datatypes of expressions in the parameterized query are re-derived with any parameters and variables having their inferred encryption schemes. Encryption key metadata corresponding to the inferred encryption scheme set is loaded. An encryption configuration is transmitted to the client that includes the inferred encryption scheme for any parameters and variables.