File name conventions and extensionsΒΆ
Each logical Sculptor data file consists of three physical files: the actual data file, its ISAM index file, and its data dictionary. There may also be secondary index files.
A data dictionary file has a .d extension. The basic file name is specified when a new data dictionary is first saved in the ddeditor program. This name is used for all the physical files and directories associated with this keyed file. They are distinguished from each other by the file extension.
The file name is normally an indication of the type of data which is to be stored in the file, such as names, invoices, control, codes. For reasons of portability it is recommended that file names are no more than eight letters long.
Different extensions are added to the basic file name by Sculptor to provide names for all the physical files and directories which are needed for this particular file. These are summarised below:
filename |
The data file, which contains all the data for all the records in the file. All key fields and data fields are stored. The index (.k) file is used to access the records in the data file. |
filename.k |
The index file. This stores the key fields for each record in the file together with a pointer to the data file indicating where the full record can be found. The index is dynamically maintained and is correctly sorted at all times. If a file contains key fields only, it is possible to dispense with the data file and have an index-only Sculptor file. |
filename.d |
The data dictionary file. |
filename.x |
A directory for the storage of secondary index files. The directory is only created if secondary indexes are specified. |
Once the data dictionary filename.d has been created, the other files are created and initialised using the Sculptor newkf program.
RELATED TOPICS |