Techniques for object relational mapping in database technologies are described herein. According to one embodiment, in response to a query statement for accessing a relational database, a syntax tree is generated to represent semantic information of the query statement, where the query statement has a boolean parameter and is implemented as an SQL object. A data type of the boolean parameter is predicted based on the semantic information obtained from the syntax tree in view of a structure representing the syntax tree. The boolean parameter is configured to be either a numeric value or a string dependent upon metadata used to map the SQL object to the relational database. Other methods and apparatuses are also described.