semantic integration

Central to the expressor solution is the concept of semantic integration, the process of mapping fields from multiple and diverse external data resources to data types and definitions that are then used exclusively within expressor projects.

The input to the semantic rationalization process is the metadata describing the data that will be processed and emitted by the expressor application. The output is an image file and entries within the listings of terms, term abbreviations, and names comprising the dictionary definitions that will be used in subsequent semantic rationalization efforts.

Image files are specific to the resource for which they were written, but different image files will map the same common name — the definition — to differently named fields in their corresponding data resources. For example, the definition “product_name” may be mapped in three image files to the rdbms table column names “prod_nm” and "pname" as well as to the data item “pro.name” described in a COBOL copybook entry.

The expressor solution represents all data as one of five expressor types — byte, datetime, decimal, number and string. Each definition is associated with an expressor meta type, which is a descriptive alias (e.g., binary or id) for the actual expressor data type (i.e., respectively, byte and string). The meta type assigned to a definition, and its underlying type, may be different from the type assigned to the data in its resource.

The important concept is that individuals developing expressor data integrations work only with the definition names and never need to refer to—or even know—the names used by the actual data resources. Consequently, all of the scripting code and business rule development — referred to as semantic integration — use the definition names, thereby providing a decoupling of the integration design from the physical environment.

As part of the semantic integration paradigm, it is important to note that all transformation code and business rules refer to the data fields using their definition names and not the names used by their respective resources. The expressor illustrator scripting window, coding aids, and schema viewers show only the definition names and access the definition-specific business rules. Consequently, all data manipulation within the expressor processor uses these semantically rationalized definition names.

Only when data is read into, or emitted from, the expressor integration does the expressor processor use the resource-specific field names. With expressor, data transformation and business rules are 100% reusable across the enterprise. For more information, learn about smart semantics.