1. A non-transitory machine-readable storage medium storing one or more sequences of instructions comprising instructions for generating a graphical user interface, which instructions, when executed by one or more processors, cause: generating an expression pattern field, of the graphical user interface, that is configured to accept user input specifying a transformation expression pattern that specifies how to transform first input data into modified input data; generating parser sub-definition fields, of the graphical user interface, that are configured to accept user input specifying two or more parser sub-definitions, wherein for each parser sub-definition the parser sub-definition fields include: a first field configured to accept user input specifying a portion of the transformation expression pattern; a second field configured to accept user input specifying a component of one of a plurality of object property types of an ontology of a data store; wherein each component is associated with a data type of data; wherein each parser sub-definition, of the two or more parser sub-definitions, specifies how to transform a portion of the first input data into a portion of the modified input data that is to be stored in the component of one of the object property types; storing the transformation expression pattern in association with the two or more parser sub-definitions, wherein the transformation expression pattern, if matched to the first input data, would cause storage of portions of the first input data in components of the object property types that are specified by the two or more parser sub-definitions.