StreamV can be run on several different databases. The demonstration system is delivered with the native database that is built into Visual Dataflex. The system can also run on SQL, DB2 and other database platforms.
For the purposes of this section (data conversion and system startup), we will only discuss the Native file structures. Sql based systems make use of the standard SQL file structures
The StreamV database contains over 120 different database files. Each file (such as the company file ) in a dataflex database has several components. These include
Def files: Database definition file.
Tag Files: The tag file lists the fields by name in sequence.
FD Files: The FD file relates each file and field number to the name given to the field or file.
Hdr Files: The Hdr file stores file header information for each file.
Dat File: The actual data file, or if the file is compressed, the file header information that is not stored in the VLD file.
VLD File: The compressed data file
Index (K) Files: The .k1 - .k16 files are the online indexes for the database file.