The components for single-tier AcuODBC are the following:
ODBC Driver Manager
The ODBC driver manager is typically provided by Microsoft. Its function is to receive calls from the Windows application, establish which data source driver is being used, call the driver (in this case, the Vision driver, AcuODBC), and load it into memory if it is not already there.
Most often, the driver manager is included with the ODBC application driver and is installed along with the application. For some products, such as Microsoft Excel, the driver manager is installed automatically if you choose the ODBC support option while installing the product. (The ODBC support option tends to be part of the "custom" install process.)
AcuODBC requires Version 3.5 or later of Microsoft's ODBC Driver Manager. If you do not already have this version installed, it is installed automatically during installation of AcuODBC.
ODBC Driver for ACUCOBOL-GT Data
The ODBC driver for ACUCOBOL-GT data, known as AcuODBC, is provided by Acucorp on your product installation media in the form of a dynamic link library, "ACUODBC.DLL." The product code and product key that you receive from Acucorp determine whether or not your driver can access remote files via AcuServer.
The function of the ODBC driver for ACUCOBOL-GT is to receive SQL commands from the ODBC driver manager, and translate them from SQL to Vision or relative file I/O using Acucorp's data dictionary files.
Data Dictionaries
Because the ODBC standard typically involves relational databases, ODBC-enabled applications execute operations on databases using SQL. While SQL databases handle I/O at the column (field) level, COBOL handles I/O at the record level. For this reason, AcuODBC must map database fields into COBOL records, and map the COBOL records back into database fields.
To perform field/record mapping, AcuODBC consults data dictionaries that are generated by the ACUCOBOL-GT compiler. These files are known as extended file descriptors, or XFDs, and are created whenever you compile with the "-Fx" or "-Fxa" option. The detailed structure of data dictionaries is discussed in section 6.1 "Data Dictionaries".